Share your amp and speaker building projects with us!

[Rob]

All,

I have just accepted the honour of moderating this forum. I figured it would be an easy job because there are always more buyers of store bought audio equipment that builders of same, so this ought to be a piece of cake.

We'd love to see photos and stories of speakers you have built. The same goes for amplifiers, especially tube amps, one of my special interests.

I've been an avid builder of electronics all my life and have made a living crafting technology in my own shop. I feel that I am well qualified to look after things here because of my keen interest. You may have seen the full range exponential bi-radial horns I recently completed or the 805 SE amp that I am planning to build now.

I notice that many posts that could adorn this forum end up starting on the Tube or Speakers forums. How about starting those here in the future? Let's make this as good a forum as some of the others here have become. It will be a bit harder after all, you have to Do It Yourselves, but hey, sometimes its worth it!

There's nothing quite like the feeling of satisfaction one gets from crafting something with your own mind and hands, and then showing it off!

Rob

[Wardsweb]

OK, I'll jump in here with a little project I did for some subwoofers for my home theater

It was a way to salvage some old cabinets.
recut them for 18" McCauley ultra sub drivers
http://wardsweb.org/audio/speakers_images/cutout_thumb.jpg

make some tuned radius edge ports
http://wardsweb.org/audio/speakers_images/portbuild2_thumb.jpg

line and brace them
http://wardsweb.org/audio/speakers_images/foam_thumb.jpg

to the finished deal
http://wardsweb.org/audio/speakers_images/sub_close.jpg

[Rob]

Wards,

Very fine job there. 2 Questions.

1). Did you place the port lengthwise from the woofer to gain bandwidth over the more common, symmetrical placement which would have seen it centered and vertically aligned as per your photos?

2). What made you go with the more expensive open celled poly foam absorber rather than simply stapling pink fiberglass wool insulation inside the cabinet? I use that stuff and find it just fine, and it is inexpensive.

Thanx for sharing.

Rob

[WildWest]

Well great Rob! I coudn't of thought of a better person for the job myself. Your deep background is gonna come in mighty handy me thinks. As an electrical contractor and an extreamly talented fellow LOL ;) why I can get into about anything but my education and background is not nearly what I wish it would be for this paticular phase of electrical/electronics. HEY, at least I can keep from killing myself in there! (snicker) Having someone like you around to bounce things off of will be pure gold!

You know, I need a friggin digital camera sumpthin bad! I would be shooting pics of my Thorens TT journey through the various mods. Only thing I have on line is the crossovers I built for my main speakers. And shoot, that wern't nuttin... :dunno:

[Rob]

WW,

Many thanx for the warm welcome. Nice x-over. Say .. are those interconnects? :)

Rob

[Wardsweb]

Rob nothng as grandios as bandwidth optimization. It was making the best of what you have. The cabinets were Klipsh protoypes that used a conventional bass driver and horn loaded mids and highs. Given the size of the opening, I calculated the depth taking into consideraton the final internal port dimensions using 3/4 MDF. The radiused edges were to eliminate "huffing".

As for the egg shell, I get it free from my brother-in-law. He is the regional manager for Victory Packaging. One of the top five corragators in the country. Comes in real handy when I need boxes or any packing material. Otherwise I dought I would use 350# double wall air freight shipping boxes for my Ebay sales. Sure impresses the people when they get their gear. :D

[WildWest]

But a DIY none the less. Kind of fell into it today. As I was in a buddies awning company welding shop I look in the corner and see a piece of 6" x 6" x 3/8 thick square steel stock. Came up to thigh hieght. Friggin thing must weigh about 80 pounds, ya know. So any way I say to the shop welder. "Hey man, can you cut these big ole lag bolts here down and weld one into each corner for spikes?" He said no prob and before you knew it I had a new turntable stand that would spike through the carpet and couple to the concrete. This is much better than the stand I had and should make for a extreamly ridgid platform for my TT MDF sandwich shelf. I tell ya, once I get the Dynamat and blu tak in the Thorens like it should be why, ummm...Vibration? What's that? ( I really need a record clamp to top this all off! ) :boink:

[Rob]

WW,

Heavy Metal normally should belong in the Music Forum, but since it is DIY I'm glad you posted here. That should dampen the ol' vibrations pretty well! :)

As a public service for the members that believe that speaker wires sound different and wish to put in something like this damper plate, I should also suggest to make sure that the metal plate is degaussed or else magnetic earth fields concentrated in the plate could adversely affect the magnetics of your phono cartridge. It is easily shown with nothing more sophisticated than a pocket compass that the plate acts as a magnetic field concentrator, it's absolutely true.

Placed in what is practical from my perspective, I believe that non-inductively run, parallel #16 or larger stranded copper is entirely adequate for speaker cables and that the magnetic fields concentrated in your plate won't cause a noticeable difference in the sound of vinyl over the other pops, scratches and mistracking, etc. associated with that medium. :) However I am certain that if you paint it satin black it will make the sound noticeably better! :D

Rob

[WildWest]

Hey Rob... I guess I didn't explain it all to well eh? It's not a plate, it is a long 36" square 6"x6" steel tube for the stand. The top TT shelf is two pieces of MDF sandwiched together with rubber inbetween. The heavy metal stand isn't very close to the turntable. I feel confident that I don't have any magnetic earth feild problems but you are right. They would tend to concentrate in metals but the degree is small. I guess if I slammed it with the sledge hammer it would tend to help align the electrons with the earths magnetic field. BUT! I don't plan on doing that LOL

"Heavy metal, music section" LOL cute, cute. ;)

Oh and it will be satin black... (snicker)

[Elliot Thompson]

Hey are those Speakers McCauley?

They resemble them very much.


The cabinetry looks beautiful. Very rich finish.

[Night Wolf]

well, I completly restore my JBL L100's rewired all internal wiring, sand them, stain, polyeurthane etc....

here are a few pictures of before the restore:

well, these pictures were taken with my old IBM NetCamera, so they are not the best, but you get the idea

this is before I ever started, only thing I did AFA doing anything to them was take that one woofer out:

http://audiokarma.org/forums/attachment.php?s=&postid=16651

http://audiokarma.org/forums/attachment.php?s=&postid=16663



http://audiokarma.org/forums/attachment.php?s=&postid=16664

all the wire is now 16ga. RS mega cable

http://audiokarma.org/forums/attachment.php?s=&postid=16665



http://audiokarma.org/forums/attachment.php?s=&postid=16680

http://audiokarma.org/forums/attachment.php?s=&postid=16681

and this is after the resteration, in these pictures I don't think I had re-painted the front baffle black yet, either way, I am real happy wih them:



http://www.audiocircle.com/circles/galleryimage.php/album05/pdr_0134.jpg

http://www.audiocircle.com/circles/galleryimage.php/album05/Pdr_0218.jpg

and here is a picture I just took, you can still see the chips, but it isn't bad (kinda cool, lol I dunno) but the stain and polyeurthane really helped it out

[Night Wolf]

hmmm I guess they don't like me to link the pictures on their server lol, just right click it, and click propeties, then you can see it (either clck the link or copy+paste)

these are the 4 holes on one of the speakers, the stain really never stuck to the wood putty, but it's ok, its not too bad either

[Night Wolf]

ok, so it's not the best picture, but this is after (well just now took it) I repainted the front baffle, looks far better then before.

so this is my little project, it came out real nice, my soldering isn't the best and I had a few problems with it, but it's ok, I just wanna get these things working already.

and in 2 weeks I am going to be starting a DIY rack for my system.

[gonefishin]

Hey there Night Wolf...looks like your starting to get into DIYing...COol...congrats. I know you've done a number of things to your speakers so far...looking good.

I'm just getting into this DIY thing too...and it sure is nice that we have audio sites like this one to help us along...sites like this provide a great place where we can get suggestions from those with more experience than us...not only to help us on our current projects...but for thoese future ones too ;) For me...AK as well as the HE forum at AA (and other individuals) have been extremely helpful to me...and I can't thank these guys enough (thanks again guys:) )


No matter how any of your projects turn out...have fun!


take care>>>>>

[CarlV]

These are monoblocks I built at the Randall museum last year. They are direct reactance drive designed by Jack Elliano with
modifications by John Atwood. It has SS rectification as it is not
in the output circuit in this design. There were 12 of us in the group doing these. Wish I had taken more "during" pics.

[CarlV]

Bottom Side:

[CarlV]

Just after doing the finish:

[Rob]

CarlIV,

That's a terrific project. I have learned that fellow AK'er BillF is currently involved in a similar group effort to build 300B monoblocks based on the WE 91 circuit. I think about a dozen amps are being made.

I've resized your images to fit on the page. We strive to keep file sizes and download times manageable. When posters can do this themselves it is appreciated.

Thanx,
Rob
Moderator

[CarlV]

Thanks Rob, I will learn how to do that for the next time. One of these days I will figure out the avatar trick too.
Carl (The Rookie)

[Andy_G]

http://users.tpg.com.au/users/gradds/

Enjoy the music !!
:nutz:

[Volvotreter]

Hi there,
I just finished my round tractrix horns and I'm very happy with them:

http://www.volvotreter.de/pics/07310001.jpg

The round horns still need some stands to be able to move them further back, to be time aligned with the midbass.

All speaker systems are DIY:
- Kipschhorn sub (far right)
- 150Hz tractrix midbass with EVM12L
- 320Hz round Tractrix with 2" Fostex D582
- Fane ST5022 Tweeter

If you like to see more information/pictures go here: My Hornspeaker related Homepage (http://www.volvotreter.de)



Erik
:DVolvotreter:D

[Rob]

Erik,

Wow! Beautiful job. I enjoyed your well done website showing the building of these. Clever tool that lathe.

Did you try the midbass horn without a port on the rear chamber?

BTW, I love the color scheme on your speakers.

Rob

[Wardsweb]

WOW ! Those are fantastic. Kudos !
I've added them to the photo gallery.

[WildWest]

Very sweet indeed! I would LOVE to have some speakers like those. I also dig that color scheme! Great job, wish I could hear them. :thmbsp:

[Volvotreter]

Hi Rob,

Originally posted by Rob
Erik,

Wow! Beautiful job. I enjoyed your well done website showing the building of these. Clever tool that lathe.


I thaught (very) long time about how it would be the best way to make precise manufactured round horns in an acceptable amount of time. A lathe was just a logic consequence.

I will most likely not only build a single pair of horns. I have an other pair of drivers to test and swapping horns takes too much time. When comparing speakers, I prefer to do this without large breaks.

If it makes sense to build a lathe on your own is a different storry ;)

But since I enjoy DIY, it was an additional challenge.


Did you try the midbass horn without a port on the rear chamber?


I never had them ported. It's a sealed backchamber, although a tractrix horn is too short to cancel out throat reactance with a tuned backchamber. Keeping them closed just avoids sound radiation from the back interfering with the sound radiated from the horn mouth.

In addition, I think porting a (tuned) backchamber makes no sense because the port will be always at least 5dB down compared to the mouth and it's also too far "away" from the mouth (delay => interference).

Erik
:)Volvotreter:)

Moderator's note: I didn't edit this post but accidentally hit the Edit Button instead of the Quote Button. Old fumble fingers tends to do this once in a while and when it is one of my forums it gets really confusing for a while. :(

[gonefishin]

Eric...great job...great looking speakers...great ta have ya post it here.

[Billfort]

I love your speakers Erik, I saw your website a while ago and saved the link thinking “this” is the way I’m going to build something like an Edgar Titan someday – if I ever have the room. I especially like the way you built those curved side front horns for your midbass, the nicest implementation I’ve seen at doing this.

And that lathe! Fantastic, over the top stuff – very cool the way you incorporated that steel template arrangement to accurately reproduce the curve. When I saw that I thought how great that feature would be – I work a lot with CAD, sheet metal and NC turret presses – I can just imagine the fun you could have with that, drawing various flares, knocking out a template and spinning a horn.

Ever thought about a small tractrix flair that could be retrofitted to an Altec 604? :D

Billfort

[Volvotreter]

Originally posted by Billfort

Ever thought about a small tractrix flair that could be retrofitted to an Altec 604? :D


You mean the 604 16" coax? Do you mean to replace the horn of the compression driver or to add a horn sourrounding the 16"?

Both shall be possible, however, if you want to add a horn to the 16" it must be quite huge to have a positive effect. For the compression driver it's more easy although I do not see how the horn is attached to the speaker. May be this could cause problems.

http://www.voiceofthetheatre.com/images/604E.SuperD.1.jpg

But it would be interesting to see if the sound of the compression driver will improve from the tractrix flare. Perhaps the round horn could be also of advantage in regards to reflections of the 16" to the back of the small round horn. It would be a smaller "obstacle" to the sound radiated by the 16" than the original rectangular one!?

I hope one can understand what I'm trying to say (I'm not native english).

Cheers

Erik

[gonefishin]

huh...replace the original Altec horn in a 604 with a little tractrix...huh...interesting idea!

Volvotreter...wards put a pic of your speakers in the gallery...hope you don't mind. here's (http://www.audiokarma.org/gallery/showphoto.php?photo=247&password=&sort=1&cat=515&page=1) a link to them.

[Rob]

[QUOTE]Originally posted by Volvotreter
[B]Hi Rob,



I thaught (very) long time about how it would be the best way to make precise manufactured round horns in an acceptable amount of time. A lathe was just a logic consequence.

I will most likely not only build a single pair of horns. I have an other pair of drivers to test and swapping horns takes too much time. When comparing speakers, I prefer to do this without large breaks.

If it makes sense to build a lathe on your own is a different storry ;)

But since I enjoy DIY, it was an additional challenge.



I never had them ported. It's a sealed backchamber, although a tractrix horn is too short to cancel out throat reactance with a tuned backchamber. Keeping them closed just avoids sound radiation from the back interfering with the sound radiated from the horn mouth.

In addition, I think porting a (tuned) backchamber makes no sense because the port will be always at least 5dB down compared to the mouth and it's also too far "away" from the mouth (delay => interference).

Erik
:)Volvotreter:)[B]

Erik,

Your english is very good. I had no problem following your thoughts about the Altec 604 coaxial loudspeaker.

When I looked at your website pictures of the midbass horn I thought the round black item on the rear of the cabinet might be a port. I did not look at an enlarged version of that picture. While it is true that this back radiation would be much lower in amplitude, bass reflex design has been combined to extend the low frequency response of a compact front horn system. For good example is the Altec A-7 Voice of the theater, although the reflex port is in the front.

I am still in the steep vertical part of my learning curve when it comes to horn speakers. About a year ago I built a large pair of 50 Hz full range bi-radial horns using the Selenium 12" coaxial loudspeaker which has a 2" titanium diaphragm compression driver firing through the woofer magnet for my home theater. They turned out quite nice but one thing I have to correct yet is bad energy storage around 375 Hz. This gives a horn colored sound in this region. I believe it is a standing wave from the driver to the horn mouth. I may try to correct this with absorber on the inside surface of the flat vertical inside walls.

I am going to have fun reading that material you have posted on your website. Thank you.

Rob

[Rob]

One more shot showing the inside of the horn.

[Response34]

Well, with so much time spent with the Jolida gear, I seem to have a good number of spare parts lying around.

Below is a picture of what was originally a gutted Jolida 302A from 1996. Started out as a bored rainy Sunday project when the family was out of town (again). I took the chassis and threw on a quick gloss black paint job, moved the main circuit board up top and installed a few upgraded parts (more than it may appear from the photo), upgraded the power supply and installed HEXFRED "Ultra Fast - Soft Recovery" diodes in the rectifying bridge. I think I will use this piece to try out some new circuit changes for the Jolida 302 and 502 amps. It is currently running as an EL34 based 302 running in triode.

It is obviously not finished and still needs some cosmetic improvements but all that needs to be done to fire it up is install the power switch. Afterwards, it will get a custom made 1/4" Cherry wood face plate. The two holes near the volume knob will soon house toggle switches, one for the source selection and the other to turn of the Blue LED power indicator light. It is wired in Cryo treated 22 awg stranded copper

[Response34]

Here is another one in the works. This may end up in my personal system as I am looking to add some airbrushing to it also. Being an automotive painter for so many years, I have to do at least one tricked out paint job on an amplifier chassis. The base coat you see here is Candy Apple Red Metal Flake and the chassis is a brand new Jolida 302/502B.

I won't get into too many details of what this amp will have for modification but I am doing a step-by-step construction of this amp on my website.

[Haoleb]

airbrushed amp eh. sounds cool. what would you airbrush on it though? flames wouldnt work. thats just bad luck already. what would be cool is a Pink Floyd collage amp. O yea!

[Response34]

Funny you mention the flames, I was thinking the same thing also in regard to being a bad Omen but still considering it. Kinda like my own Hotrod version.
I was thinking of doing the graphics in Green Candy Metalic (anybody follow Jessie James - Mortorcycle Mania) with another top coat of the Candy Red followed by several coats of clear, this is all laquer paint, for a very subtle appearance.
I know it sounds a bit out there but it would truly be done in good taste and not like some 50's hotrod Ford coupe.
I was also considering a spider web, actually a real one (I can explain later). I did this on a custom 4 foot remote control racing boat a few years ago and had everybody and their brother asking me to do it on their boats. Yes, I use to race remote control gas boats. You ever see a RC boat flying across a lake at 70 mph. It's a blast!!
But anyways, I don't know. I haven't decided how to proceed yet. I have a few other chassis now in primer and also some new ones still in the box that I can paint up also.

I know, you're probably wondering how I can run a business if I keep so many projects for personal use. My answer is: I started out with the same passion and interest in this hobby as everybody else here. Business is business and my hobby is my own.

[Rob]

34,

On that amp you have placed the PCB on top of the chassis I note you have wired the 6CA7's in triode. Those babies are gonna put out mucho radiant heat and that will not do kind things to the circuit board and the components mounted thereon nearest the output tubes. Just a cautionary observation from someone who recently went triode with P-P 6CA7's, had to up the bias to just fringe detectable red plates in the dark to get the 'tone' (I'm within tube specs) and now suffer a heat issue.

That automotive painting talent sure brings a new perspective to amplifier building here. We're looking forward to seeing more!

[Response34]

Those babies are gonna put out mucho radiant heat and that will not do kind things to the circuit board and the components mounted thereon nearest the output tubes.

Hi Rob,
Actually, there is more space between the power tubes and PC board than may appear from the photo plus I have custom heat shields that will be placed between the tubes and board. I did consider this when putting it together. I will obviously keep an eye on things.
What kind of heat are you getting from your amp? This unit does not generate much more heat in triode than PP.

[Rob]

Originally posted by Response34
Hi Rob,
..... What kind of heat are you getting from your amp? This unit does not generate much more heat in triode than PP.

Quite a bit, but its a dry heat! :D

In P-P UL pentode mode I had the tubes biased at about 60 mA for the pair. This put the amp into class AB mode. Everything ran really cool. When I switched to PP triode I upped the cathode current by reducing the negative grid bias so that the pair of tubes pulls 116 mA at idle and about 148 mA at full output. I also swapped out the 5V4 rectifier to a 5U4 which gave me ~25 volts more B+ where I needed it to recover some output power lost to the switch to triode. I am therefore now running class A since I almost never tax this amplifier. I am at the rated dissipation of the 6CA7's which is 25 watts per tube. Plus the heater power of 10 watts so that is 35 watts x 4 = 140 watts of heat in the space where the output tubes live, compared to half that previously in UL PP.

I went from 24 watts/ch to 14 watts/ch but boy did I get TONE! :)
I also got better damping factor as a result of the lower plate Z in triode mode and the fact that my xfmer was 3400 ohms, a little low for pentode but a better match for triode since I'm loading it to under 2K reflected Z. This amp now drives a pair of large, efficient ~3.5 ohm loudspeakers on the 8 ohm taps like a champion!

[WildWest]

Hey Rob...Ya know, I am thinking about swapping a few wires here and there, tossing in a few resistors to change my Dyna ST 70 from PP pentode to PP triode. I have detailed instructions on how to do this from Ned at Triode Electronics. Real simple to do but is there anything you can add here? There is a 1K feedback resistor per EL34 that people remove too due to the higher inherent damping factor and low plate resistance of triodes and tubes wired as triodes. Should I try removing that resistor? What's your take here? Thanks bud! :)

[Rob]

WW,

You shud put a 1K ohm 1 or 2 watt carbon resistor between the plate and grid 2 of each EL34. This isn't FB, it is a current limiting resistor to help your EL34 live longer. Grid 3 goes straight to the cathode like the suppressor normally is internally wired in 6L6's, KT-88's and such, at least that is how I wired mine. I was tempted to try true triode with all 3 grids tied together as the control grid (you can do this on an EL34) but haven't had the time or ambition. Perhaps if anyone else has tried this mode of triode wiring an EL34 they could chime in here? :)

You may have to adjust your bias to draw more tube current. I found that I got noticeably better tone when I went heavy towards class-A PP. I increased my no-signal cathode current to 118 mA per pair of Mullard 6CA7's from about 60 mA before in ultralinear AB1. Full signal current climbs to almost 150 mA. I have about 420 volts on the plates. More heat, less tube life, less output power, more tone. It's all about tone! :thmbsp:

[Rob]

Hey Mike,

Is this a speaker project you've been working away on while we haven't heard from you in a while? They look like a nice project. Big enough to interface with the room (that's where small speakers have no chance). I'd love to hear them! I guess I don't understand where the 15" woofer fits into this at 35 Hz since the horn opening I see at the bottom seems to be described as for the pair of midrange cones.

What amps are those in the bottom of the rack?

[timoteus]

I built these a couple of years ago. Since then I have built some Paraglows and a Seduction in black powdercoat, polished brass, and rosewood to match the speaker cabinets. I don't have pics of those though. I need a digi cam real bad.

http://www.homestead.com/sparkgap/files/TimoteusHeds.JPG

[Rob]

Timoteus,

Ahhh, the Hedlund Horn. Very nice job. Thanx for sharing. What drivers 'ya using?

Sounds like you did a nice job on the amps too. Hope you can show pics soon.

[timoteus]

I am using the Lowther EX3. I got them when they were first released, six months later they went to the rolled edge whizzer. So now mine are either obsolete or a collector's item, take your pick. :scratch2:

[gonefishin]

Here is my Shiva MKIII in a 54l sealed cabinet, next to a pair of SEAS Njord speakers my friend and I built. I have possesion of these awesome speakers till his living arrangment are settled, not bad , in return for me helping him build them.

below is Lurch's HT system

[gonefishin]

below is Lurch's sub pic

[Lurch]

I did'nt like the idea of cutting a hole in my sub cabinet after spending alot of time bracing it so I made a quik box to house the amp in, also I plan on building a sonotube shiva and I can use the same amp to run one for ht and the other for Music.

[mikee.e]

Hi! my name is mike elliston

a little about me=
i live in NZ im 20 years old,im studying ELectrotechnology at polytech.

Rob- how long is that horn with 12" ? it looks like a midbass with big mouth.

volvotreter-your horns are very awesome,when i get the time/money/space i will build horns like that,a friend in Australia Adrian Mack has made his own Tractix horns
adrians horns (http://www.audioasylum.com/forums/pi/messages/12014.html)

his site isnt up to date yet,when its finished il post a link,he has JBL2370 HF with P audio comp drivers on them,and Eighteensound 18LW1400 for sub duty, and jbl2225s for midbass up to 300hz to meet his midrange Tractrix.

very nice looking
its easy to make an ugly speaker box
:(

and also u may want to see what arrived a little over 2months ago

http://homepages.slingshot.co.nz/~mike.e/jbl_files/image003.jpg





:cool:


http://homepages.slingshot.co.nz/~mike.e/index_files/image001.jpg


http://homepages.slingshot.co.nz/~mike.e/jbl_files/image001.jpg
those are with my webcam ,i have camera being developed soon


http://homepages.slingshot.co.nz/~mike.e/jbl_files/image008.jpg

http://homepages.slingshot.co.nz/~mike.e/jbl_files/image005.jpg

built this box in 2hrs of working out holes,another 2hrs of frantic glueing! (for some reason my dad wanted to get it all done in one go before the glue set)made it kinda fun! and we forgot to glue the front port shelf port baffle-so i gotinside the speaker cut out put lots of woodglue down ont the top of that join :-Dil silicon it sometime.

at first i had it against the MDF,with 4screws,it didnt like that and puffed heaps of air out the sides..so did all screws up,then got some weatherstrip like shown in my site,and put that under woofer frame face.seems to work,i still dont trust it though..

i sometimes turn it up too loud for songs which only have high bass,then a song comes on with heaps of low stuff,and its annoying me in the other room (with less than 20watt haha)

thats 97db efficiency for ya! it was either this or a Shiva(cheap piece of distortion)but i wudve gotn one otherwise i reckon


2226 in 175L ebs 33hz tuned i currently have a little Sanken 30watt amp,with a restrictive 20va transformer powering it!
ouch!
but,its Plenty loud enough,and the response is on my website-
http://homepages.slingshot.co.nz/~mike.e

its a nice rolly offy overdamped response

im going to get a 240watt amp for it to realise its full potential
i definately enjoy the brilliant sound quality of it.
This is my first real sub.i bought this 2nd hand from a guy in Australia.

it actualy doesnt have any damping material inside it on the walls :-S
but i am planning to put some in.

it does have a rising response with higher frequencies,im thinking of filtering it at 24db/octave,especially because of the EBS tuning,and my 'turning it up' at the little sub amp volume.

its in a corner position in a 2.2mx4m room,tiny room with lots of rattles with that tiny amp! can only imagine 240watts!

and my next project-Basshorn!
which i have posted Here-

audio asylum link to my post (http://www.audioasylum.com/forums/HUG/messages/56814.html)


it uses the 12" lab12 woofer from eminence (Designed specifically for the labhorn which i studied in depth)
its only a 40hz corner horn as its my first horn and its only 250L or so.

ive spent the entire year, playing with hornresp,asking questions to a few horn fellows,and finding horn info online.

if u have any questions go right ahead,i may forget to check this forum as i havent been here before..


and Lately my interests include- reading about distortion and why should i want to build a basshorn-

www.linkwitzlab.com- this man g oes into great detail in his sealed box woofer, with FFT measurements of his output,i reccomend it,he then notes that subwoofers need 2nd and 3rd harmonics LOWER than 6% or else the 20hz fundamental tone will have equal apparent amplitude to our ears as the 40hz and 60hz distortions!! and thats with 20hz Sine,i really hate the thought of having all that other sound that shouldnt be there.


this really encourages me to avoid sealed at high SPL, do ported (like my 2226) and look into horns for maximal loading!

sorry for the long post,but sometimes theres alot to be said!

Regards,
Mike in NZ



http://homepages.slingshot.co.nz/~mike.e/pic/thumb.jpg

[omer]

Welcome to AK Mike, glad to have you aboard! :yippy:

[Rob]

Mikee.e,

Welcome to AK! It sounds like you are having lots of fun down under. :) That was lucky finding the JBL driver at a 2nd hand shop.

You asked about my large 50Hz horn. The driver is a 12CO1P Selenium. FS is 45.58 Hz. The horn is really a throw together and was made to be as big as I could get down the stairs into the home theater room without going too crazy, and also optimizing use of 4'x8' material sheet size. As it is I have to remove the back chamber and the driver (1/4-20 bolts) to get it into the house. The horn throat is 47" deep. Mouth dimentions are 25-1/4" x 70". The entire cabinet measures 5' 1" front to back.

I didn't do any flare calculating at all because I used a pre-existing curve of fiberglass for this project. I did everything pretty much by eye. I was looking at a 10 foot diameter molded fiberglass radome cover for a commercial microwave dish in my storage yard one day and it occured to me that if I cut 4 petals out of the surface I could make a large, apparently exponential, and truly bi-radial horn. Thus the project was born! Here is a photo where I have superimposed the fiberglass radome image with a reversed/inverted photo of same to produce the horn against the horn flare for the Altec 210 VOT horn. You can see that my horn will be longer in the throat with slower expansion than the Altec. Additionally the mouth size will be larger than the Altec, although less so than the increase in throat length. The fiberglass was flimsy once cut so before I cut into the radome I marked out my petals and reinforced them on the backside with heavy welded-wire steel mesh and automotive fiberglass short-strand reinforced polyester resin. Once installed the panels were further beefed up with lead shot mixed in the same resin. A total of nearly 10 gallons at $50.00/gallon of this polyester putty was added to make the horn flare sections non-resonant. I could have bought a pair of actual vintage classic Klipschorns for what I spent on materials for my speakers, but the Klipsch wouldn't have done the job in the space available. These were truly custom made for my theater room where a long throwing speaker was needed that would also work in the near field, and where the width between screen and wall was quite limited to less than 2 feet.

I still need to address an energy storage issue at ~375 Hz which I believe to be a standiing wave along the long sidewall of the throat, but besides this these horns turned out to be highly successful. Outdoors they go smooth down to 50Hz and then turn off like a switch. The in-room corner placement is better. The bass is very fast. BillFort, fellow AKer did a revue on his listening impressions during a visit shortly after I had completed these horns. http://www.audiokarma.org/forums//showthread.php?s=&threadid=1653&highlight=BillF+visits+RobTV

[Rob]

In case you are wondering what a radome is, here is the fiberglass radome I used. 10 feet in diameter.

[Rob]

Here are the four flare petals marked out and reinforced with steel mesh and resin prior to cutting open the radome. This prep work helped the four flare sections to retain their shape after cutting.

[mikee.e]

woah cool!

yeah i live in NZ,i was lucky to get that jbl from OZ~!!

its nice to meet some fellow music and audio lovers

because-
i started at diyaudio.com,then diysubwoofers.org(mikee12345 and mikeported)and audio asylum(toxicport.e) and several car audio forums:puke: where i blasted:uzi: away the as many lies myths untruths and modeled ppls subs



Caution rant! skip down to the end of the blue if u wish..
i have a huge list of funny things-
like - 'my mate said that square ports have no turbulence'
and ppl saying 'my 15" is tuned to 35hz,so probably urs tuned to 25hz will be fine''

just a general lack of t/s specs aswell jsut to make it more fun!
(www.termpro.com) and many -

'what about 2 of woofer x vs 2 or 1 of woofer y' ,if ppl used the search button they wud find it ....

infact i did 150 posts in less than 28days at one forum, it was SO many ppl needing winisd/modeling help,it was ridiculous

and just facts like-a 4inch port ISNT NEcessarily too big-depending on how much POwer ul use,not just cos 'my 15" uses a 4" port..

and ppl denying the use of electronic equivalent circuits and the basis of winisd in cars,which i eventualy proved why its useful to a degree..it was hard work i tell u..

:mad:

ive decided i have enough links and posts,to actualy never type a new post again at those car audio forums,i can just post a link to the previously answered question! haah.

at diyaudio.com, u must click'yes i have searched' before making a new topic

some ppl are just lazy ,or dont understand and want some oen else to do their box for them-
ive decided i will now,but only a 1min modeling in winisd,or il spend my entire life in that program ahahah!!

i have plenty of links to informative sites that sorts most ppl out

WELL thats my last months experience online,,

im really looking forward to these horns


/END RANT


that 50hz horn is so awesome!
massively tall and NO folds :D it will have great HF ability.

compare to mine which has many folds.i think the 40cm width will cause badness in response as well as folds and reflections and discontinuities...i only need 100hz anyway at the highest.

il be taking lots of pics when making later in the year!

ive modeled,and drawn up - now i have to take into account wood thicknesses (25MM)

it will be a great experience to build and measure and listen to a low distortion horn

and il learn,and decide,-should i build a 30hz or 26hz basshorn for my mate! who wants the biggest and bestest horn that he can fit,particurly as a couch,or a piece of furniture

anyway 4am must sleep now.il check out the other forums later!


btw ive only mentioned my sub-i have 1980s Philips tweeter and midrange 4" (2 per channeL) running off my dodgy sanwa 2x10watt icky mini system that il get rid of that at the first chance.


il have pictures out of my camera of all this later

and yes i love horns!

cheers all!

[Rob]

Once the petals had been cut I did a mock up and ran music through a 12" FR driver placed at the throat. By walking around the room and using only my ears I got a feel for the response pattern. The results were encouraging enough that I decided to proceed with the project.

[mikee.e]

my mates tractix midrange

Rob-really nice horn!
would adding a brace across the mouth help the resonance?

i couldnt see into the horn before my pc screen isnt bright..

cheers!

adrians tractix (http://db.audioasylum.com/cgi/m.pl?forum=pi&n=11845&highlight=tractix+horn+adrian+mack&r=&session=)

[Rob]

Mike,

There are a total of six braces made of steel bar dampened with sheet lead wrap placed at strategic points between the sidewalls of the horn. The positions where they are placed were mapped by running an audio oscillator through a power amplifier and slowly sweeping the box while detecting the exact zone centers of the vibration modes that occured in the sidewalls by hand. The positions were located with great accuracy and without these damping bars the cabinet would have been putting out as much sound out the sides as from the front. These damping bars proved extremely effective. Note that the Altec 210 does not use them and also has parallel sides, something I avoided as well!

This picture shows some of the vibration dampers installed.

The energy storage 'boom' I have now at ~375 Hz (or maybe it's ~275 Hz, I forget) is not from sidewall resonance as in cabinet vibration. I believe it to be from an acoustical standing wave reflecting back into the horn from the straight sides of the mouth of the horn.

I haven't listened to these horns in the better part of a year as I have another set of developmental speakers in this room occupying my R&D efforts. My recollection of the horn boom issue is a bit fuzzy. I plan to attack it when these new speakers are out of there.

[mikee.e]

could you feel the resonant nodes and anti nodes?

have you seen the labhorn (www.prosoundweb.com/lsp)

i have heard of ppl using accelerometers-but it sounds tricky,but a similar method

i think my 40hz basshorn should be braced enough as its folded it sort of acts as a bracing to itself.

i have 3 braces ,corner reflectors 25mm mdf ( i think i should put it all around) it will be alot more heavier but its no use making a bad resonant horn

http://homepages.slingshot.co.nz/~mike.e/horn/bracing.jpg
:) :p:

[THOR]

Rob, Triumph the Insult Comic Dog emailed me some comments he wanted me to post about your horn project I guess your email was down:

**Disclaimer the following interviews or statements in no way reflect THOR or his thoughts or opinions**

"Dear Rob,

That is an execellent project you have going on there..........................FOR ME TO POOP ON!!!!!

Sincerely,
Triumph the Insult Comic Dog"

[Rob]

Thor,

Triumph must be a teacher. There are those that can do, and there are those that cannot. The latter often become teachers.*

I could care less about what someone who cannot do has to say about my projects. They stand well on their own merits, and sometimes also on large casters. :D

*no actual teachers were harmed in this satirical diatribe.

[Rob]

Originally posted by mikee.e
could you feel the resonant nodes and anti nodes?

have you seen the labhorn (www.prosoundweb.com/lsp)

i have heard of ppl using accelerometers-but it sounds tricky,but a similar method

i think my 40hz basshorn should be braced enough as its folded it sort of acts as a bracing to itself.

i have 3 braces ,corner reflectors 25mm mdf ( i think i should put it all around) it will be alot more heavier but its no use making a bad resonant horn

http://homepages.slingshot.co.nz/~mike.e/horn/bracing.jpg
:) :p:

You don't need instrumentation to feel when the outside of a large cabinet starts to vibrate in dimensional related resonance. It is very dramatic and occurs at even very low volume levels. Of course if the surfaces you need to examine for vibration are buried inside the folds of a horn as in your design the use of remote sensors like accelerometers is necessary if you wish to perfect the design to that level of detail.

I've seen the labhorn in pictures. Interesting. Looks like a spiral shell from an aquatic animal. The response graph on the linked website looked nice except for the suckout.

[mikee.e]

suckout-midbass droop or HF lack of?

the response is One box Outside

its meant for stacks of 2 or more indoors

one guy measures 114db/1watt ,2 labs,each in a corner of his room(his HOUSE) haha :-D

ive modeld the labhorn-and i got rid of the midbass hole,by increasing the rear box volume-i think that the Volume restriction(to fit in a truck)
meant that for 2 woofers and size,only about 18L could be accomodated each- i used 30L (one woofer) and the response was flat!

a guy called 'hulkss' has done a high compression labhorn remodel

http://www.audioasylum.com/forums/HUG/messages/56004.html

notice that tom Danley modeled,CADed it,and REMODELED with the ACTUAL CAD foldings included :O talk about detail!

il just leave my horn how it is,its close enough

aslong as it loads like it says it will be a great project!

cheers

[Rob]

Mike,

I'm no expert on horns, or speakers, but I have lots of accumulated experience and an an extra large sized modicum of talent. ;) I'm just fiercely interested in learning, and building stuff with my own hands has been my way of doing this all my life. Those large horns are the first speakers I've built in almost 30 years and the fact that I tackled them completely without following anyone else's plans is indicative of the way I generally build stuff, and my sense of confidence in my own ideas. I don't think you should treat me as some sort of oracle or mentor. You probably know a lot more about horns than I do right now. I don't yet have the means to model them on a computer, so I have to do basic calculations on a handheld calculator, make models in real sized hardware, and make modifications the hard way as well. I guess if I become proficient in this field I'll want to move on and meet another challenge. I live for the learning curve. When it is steepest I love the challenge the best I think. The fact that I've made no scrap lumber in three successful experimental speaker designs now out of 3 has to say something about my own methods working at least for me.

I urge you to push yourself away from the computer and build those Labhorns! I'm certain it will be fun. :) Yes the performnce specs look impressive!;)

[Rob]

MikeB,

Any way you can lighten those pics and replace them? You didn't mention, is this your system now? Love to see it! ;)

[mikee.e]

Rob i like your DIY approach
it reminds me of ppl in NZ-just getting on with it and trying things

they just do it themselves

i may know about horns,but its a different matter if i can out it to any use! haha

(im done modeling dont worry :-D)

im not much use with wood-i get my woodcut by someone else all perfectly:rolleyes:

because its 2x12"- i cant afford,(labhorn)
so its my own 40hz basshorn first...then il see if its worth modeling up a 750L 30hz with one 12"

and im wondering maybe i cud sell one to a local AUdio place if they want some PA subs if i make more.

also the more i make,the less costly it is,and more experience,

:D

[Cory]

Hey guys, wow, a lot of great speaker projects- I wouldn't know where to start!

You might not recognize me, but I do a lot of lurking and post over at the vintage TV boards (Hey Rob!). I'm also one of those youngins' who plays with tubes, 22.

Anyway, I just finished, well, mostly, my year-long integrated system. Based on Rozenblit's grounded-grid preamp, a 'Headwize' active EQ, and 150w EL34 monoblocks. Specs called for EL509s but I had nothing but trouble during testing so changed everything over. There are lots of little tricks-infrared remote, motorized controls, microprocessor based warmups, inputs, sleeptimer, etc. etc. It's pretty as a picture under the chassis, but I'll wait until I put the finishing wood panels on it and get the software updated for the LCD for pics. This sucker's been the bane of my existence for quite a while!

Whaddaya think? :dunno:

One thing's for sure....it's heavy!

[Cory]

Here's a pic with the lights turned down- the front row indicators are neons that backlight letters corresponding to the controls. The LEDs are for preamp HV, filaments, Powamp HV, sleep timer and remote. The red glow around the vol knob increases as you adjust it, there's a toggle on back for dot mode. The eye is a dual 6AF6 with a 12ax7 hiding under the chassis for gain. Left side of the chassis is the trans for the filaments, regulators and recitifers for the eq and pre (which are the 9 miniatures). For the power amp section, the screens are regulated to a bit over 400v, the plates at 700v. Heehee! :zoom:

[mikee.e]

THAT IS SOO COOL

i want one!

i dont care what it does! need one! haha

u cud use that as props on movie sets for alien spaceship controls!

when i make my own amp, il need to make it as good externally!

Cheers dude!

[Rob]

Cory,

You do me proud when someone choses a forum that I have the priviledge of being moderator for to display such a work of art as you just have! I can see why it took you so long to build. Nice going! I am almost speechless. :) That variable glow around the throttle is a way cool idea too!

[Cory]

Thanks for the compliments guys, it means a lot. Mikee, let me know when you make that next amp, I've got a couple tricks up my sleeve.

It's tough to tell in the pics, but I painted the chassis Cadillac white diamond (I'm a Cad fan) and used blue metallic for the xformer end bells and also spruced up the vol knob with a concentric ring of blue. The knob is actually from an old freq counter...the rest of that is going towards my vacuum tube digital clock project! :eek:

Any big projects for you guys?
Cory

[mikee.e]

Hi cory
well actualy im planning on fixing my car audio first,DIY style..:rolleyes:
but 'car + audio' isnt allowed here,im sending u a PM about it,


Cheers!:D :D :D

[Mike Caldwell]

Hello
While this may not be a home system, I designed and built all of the speaker cabinets,stage monitors, many associated equipment racks along with making miles of various cables.
The low end cabinets are loaded with two JBL 2226h speakers each with a total of eight cabinets. The mid-high cabinets are loaded with two B&C 12PE32 speakers and a Electrovoice DH1A high frequency driver on a JBL 2385 horn with a total of six cabinets. The stage monitors are loaded with a JBL 2206h speaker and a JBL 2425 or 2426 driver on a RCF HP6040 horn with a total of eight monitors. The main speakers are ran tri-amped with 1600watts to each low end cabinet, 900 watts to mid range and 300 watts for the high end in each mid-high cabinet. The stage monitors are bi-amped with 900 watts on lows and 300 on highs. The amps are all Crown and QSC. Processing is TDM, BSS, Drawmer, TC Electronic, Lexicon, ARX, Symetrix, the mixing board is Allen & Heath.
As a side note to those of you who are participating in the “Music Box”, the live recordings I included in the box were made through this system. The pictures were taken at a summer music festival that I provided the audio production for, the band playing is included on the CD in the “Music Box”.

This is the perfect example of a hobby gone out of control!

Mike Caldwell

[gonefishin]

Mike Caldwell...now that is cool! Thanks for sharing. You've got some pictures of audio at it's best.


Mikee.e...I love the avatar! Your speakers look great...I just wish I could listen to all the speakers I see people (like yourself) build.

Cory...I missed your post (until now) First off...I usually don't check out the vintage Tv boards...so I may have missed many of your posts. Either way...good ta see ya...welcome aboard!
Now let me say...holy moly! :eek: That amps is extremely impressive looking. I hope you share some of your thoughts (on tube amp design/construction) with the rest of us. Don't worry...there are some of the guys who you'll carry a good conversation with. Myself...I'll mostly be reading what you guys have ta say ;)


thanks guys...all great projects!


(hey Rob...:thmbsp: )

[stabist]

Hi!

Here are some of my DiY attempts - my first serious project was my interpetation of mr. Pass's Zen v4:

[stabist]

And internal look:

[stabist]

Ofcourse little Zen got also his matching Bride ;)

[stabist]

NAd external view:

[stabist]

Hmm - OK, I made a mistake- Zen and BoZ were my first seriuous amplification projects ... But my very first project were these speakers build 10 yrs ago - and they are still my main speakers ... Based on Focal c500 DiY kit ...