The thrill of rotating speakers

[thomo57]

like a lot on AK l collect "gear"
Some l keep some l sell.
I've posted about these speakers previously.
I originally bought these Coral 10CX drivers for literally a song in an old cabinet years ago.

Done my homework looking up what they were originally mounted in and then got the urge to redesign the original cabinet design which l did with some advice both for and against from AK members.

I kept the cabinet dimensions the same but reconfigured the port dimensions so the port was full length of the cabinet.

Got a friend cabinet maker to whack them up which he done in a day or two.
They weigh about 70lb each, made out of 18 and 24mm mdf

I spent a few years mucking around changing the damping materials as l wasn't happy with them
As it was a pita to cut the damping each time the speakers were in and out of rotation for sometimes long periods of time
Last time l opened them up l hung a blanket of damping material in the cabinet and they finally sounded amazing so l thought two blankets would be better
So l opened them up and removed the second blanket.
I have since bought and sold several sets of speakers and have had others in rotation.
Finally pulled the Corals out again today and they just blow me away with their musicality.

I think they'll be staying for a while

 

[Retrovert]

Those are beautiful drivers and cabinets. Looks like you have a time machine.

I'm surprised the damping did not improve the sound; in the Bozak loudspeakers the hanging cotton batting curtain, the dimensions of which are somewhat critical, ensures the backwave is lost in the (lined) cabinet, much like a muffler baffle. The infinite baffle will be far more accurate than a ported cabinet because the backwave is not phase-shifted and recombined, eliminating distortion from the group delay.

As a fan of the infinite baffle I'm curious what material you used for the curtain and why it did not work. I note that losing the backwave will remove the reinforcement a port adds, so the speaker is somewhat less than half as loud.

It is nice to have speakers for rotation, especially when the other speakers are not jealous about one's polyaudio relationship.

 

[Lavane]

Very cool project!

 

[corbin]

Literally a song?

Sorry.

 

[gdmoore28]

Here's my favorite rotating speaker:

Sorry. Couldn't help it.

GeeDeeEmm

 

[sKiZo]

How do you keep the wires from getting all twisted up?

 

[Darren James]

I thought the thrill of rotating speakers is having several sets of different speakers and rotating their use!!! LOL

Cause that's my thrill of rotating speakers.... This week is AR 58s's !!

IMG_20180701_140104670_BURST000_COVER_TOP

• Darren James
• Jul 1, 2018

 

[thomo57]

Those are beautiful drivers and cabinets. Looks like you have a time machine.

I'm surprised the damping did not improve the sound; in the Bozak loudspeakers the hanging cotton batting curtain, the dimensions of which are somewhat critical, ensures the backwave is lost in the (lined) cabinet, much like a muffler baffle. The infinite baffle will be far more accurate than a ported cabinet because the backwave is not phase-shifted and recombined, eliminating distortion from the group delay.

As a fan of the infinite baffle I'm curious what material you used for the curtain and why it did not work. I note that losing the backwave will remove the reinforcement a port adds, so the speaker is somewhat less than half as loud.

It is nice to have speakers for rotation, especially when the other speakers are not jealous about one's polyaudio relationship.

Hi retrovert,
You may have misunderstood
After numerous attempts placing different damping on the cabinet walls it just didn't do it for me.
I left that in place
I then placed a hanging blanket like l found in an old Goodman speaker cabinet l found years ago.( the Goodman had two)
That was the the eureka moment.
Then l thought if one was good maybe two is better which it wasn't.
It killed the sound so it now has the one blanket.
This is a photo of the material .
I picked up a large roll somewhere in my travels

 

[jazzmans]

Yep, I roll speakers in and out of my main listening space all the time.

As of today, it's my Magnepan 2.5R (they've been there since I got them, everything else has been revolving around them)
and my Infinity Renassaince 90s. I've had them a few years now, and everytime I listen to them, I realize they are the best goddamn speakers I've ever owned. (they've been in my bedroom for a couple of years, my second main listening room)

But I'm constantly adding/changing speakers in my main room, I have hookups for three pairs wired, so It's just a question of setting and plugging in, every speaker is so different it's fun.

yeah, I'm weird


in the last week I've had
Infinity RS 4b, Infinity Qe, aforesaid KEFs, M&K s 100, M&K s 125, JM Lab Focal Cobalt 815 It's fun to compare and contrast.

 

[Retrovert]

You may have misunderstood
After numerous attempts placing different damping on the cabinet walls it just didn't do it for me.
I left that in place
I then placed a hanging blanket like l found in an old Goodman speaker cabinet l found years ago.( the Goodman had two)
Then l thought if one was good maybe two is better which it wasn't.
It killed the sound so it now has the one blanket.

I'm not sure I understand. Did you try damping material—i.e. adding mass via bitumen or asphalt products, rubber products, etc.—or an absorbing material, such as cotton batting?

The curtain was like the Bozak curtain?

This is a photo of the material . I picked up a large roll somewhere in my travels

That looks like a dense felt, which was popular at one point. I don't know of anyone who had good experience with with dense material in Bozaks or other speakers. The cotton batting is very fluffy and properly absorbs the backwave without reflecting it. Did you try that?

 

[Nemo bit]

Yep...yep umm.. hmm, Its others also..so many really worthy speakers..but which? Ok for today..Ohm 2xo for some...and klipsch C.W.s for the other..choice its a beautiful thing..

 

[sKiZo]

If you're working with DIY speakers, then by all means experiment with the different material available. Fan of rock wool myself. However - if you're refurbing an existing speaker, strange things can happen if you change from the material that was used by the designers ...

Rolling speakers ain't my thing - it takes too much work to tune a room for best response, so I've been running the same boxes for decades now. Response doesn't stop at the boxes ... the whole room gets involved eventually. Once the room is tuned here, it goes down to standard maintenance and refurb as needed to keep both me and my McIntosh XR16's happy.

 

[Nemo bit]

Ohms are the easiest to place speaker I have delt with hands down. Only requirement that is carved in stone in my experience is a ceiling.
And proper orientation to one another..pretty simple.
Cheers

 

[Darren James]

If you're working with DIY speakers, then by all means experiment with the different material available. Fan of rock wool myself. However - if you're refurbing an existing speaker, strange things can happen if you change from the material that was used by the designers ...


Love the Chair 5 feet back!!

 

[sKiZo]

Brings new meaning to the term "near field listening", don't it? <G>

Actually works quite well in a "holographic" system. Granted, the sweet spot is mighty small, but it's right where it needs to be. Also makes it real easy to reach all the buttons, eh.

 

[thomo57]

I'm not sure I understand. Did you try damping material—i.e. adding mass via bitumen or asphalt products, rubber products, etc.—or an absorbing material, such as cotton batting?

The curtain was like the Bozak curtain?



That looks like a dense felt, which was popular at one point. I don't know of anyone who had good experience with with dense material in Bozaks or other speakers. The cotton batting is very fluffy and properly absorbs the backwave without reflecting it. Did you try that?

No l didn't try any rubber or bitumen materials
Which maybe something l can try when l get the urge

I tried rock wool
egg crate foam,
sound deadening foam with a silver foil backing

They now have that cotton batting on the walls throughout including the curtain.

 

[Retrovert]

I tried rock wool
egg crate foam,
sound deadening foam with a silver foil backing

Yeah, those materials are all 100% guaranteed to not work in infinite baffle, and pretty much everywhere else.

The foam is useless, I don't know why anyone tries it. The rock wool will not absorb the backwave. The main use of stuffing is to slow the backwave, as in acoustic suspension.

They now have that cotton batting on the walls throughout including the curtain.

Cotton batting is the only material which works in infinite baffle. In Bozaks the cabinet is fully lined on all interior surfaces and the hanging curtain creates a muffler.

Thick cotton batting is what works and it delivers results in many speakers because it removes the cabinet reflections..

 

[thomo57]

The main use of stuffing is to slow the backwave, as in acoustic suspension.



Cotton batting is the only material which works in infinite baffle. In Bozaks the cabinet is fully lined on all interior surfaces and the hanging curtain creates a muffler.

Thick cotton batting is what works and it delivers results in many speakers because it removes the cabinet reflections..

Cotton batting definitely worked for me and l still have a fairly large roll for projects.
I built some Karlson cabinets recently they are lined with cotton batting and stuffed with Polyester pillow stuffing and they sound pretty good

 

[Retrovert]

Cotton batting definitely worked for me and l still have a fairly large roll for projects.
I built some Karlson cabinets recently they are lined with cotton batting and stuffed with Polyester pillow stuffing and they sound pretty good

I have a pair of 12" Karlsons with full-range drivers and was going to line them with cotton batting when I have some hands-on time for a project. Mine are original flatpacks purchased from Karlson in Brooklyn. They came to me forty years ago from the original purchaser, and I've added a home-built K-15 which was built in the 1950s.

Have you added the PVC elbow ports? Improves the low-end response. I have not yet done this to mine.

Freddi, Grand Master of the Karlson, has described the mod here: http://www.diyaudio.com/forums/full-range/320847-karlson-cabinet.html

 

[thomo57]

I have a pair of 12" Karlsons with full-range drivers and was going to line them with cotton batting when I have some hands-on time for a project. Mine are original flatpacks purchased from Karlson in Brooklyn. They came to me forty years ago from the original purchaser, and I've added a home-built K-15 which was built in the 1950s.

Have you added the PVC elbow ports? Improves the low-end response. I have not yet done this to mine.

Freddi, Grand Master of the Karlson, has described the mod here: http://www.diyaudio.com/forums/full-range/320847-karlson-cabinet.html

I'm in no way a cabinetmaker and don't have the proper gear to do accurate cutting but l had the will to build them which l did mostly on my garage floor.
I might get my mate to build a nice pair for me
They just have an open port.
l told a friend about my project and he gave me a pair of Celestion 12" coaxials to put in them and l may even try my Goodman Triaxiom in them some time.
May even try the Corals in them as well, but will have to cot another face plate to fit the 10" driver in.
I'm in no way technically educated but actually the opposite ( technically challenged after a mini stroke last year)
But l like the idea of being able use a single driver with no technical crossovers.