Why Do I NEED a Subwoofer for My Speakers?

[whoaru99]

Here's where I got the info http://www.jblpro.com/pub/obsolete/4345.pdf

There is a graph on pg 3, and the specs listed on pg 4.

Based on the graph, I'd say -6dB looks about right for the low end spec, but the 20kHz value looks better than that. Again though, my point isn't to critique the speaker beyond comparing its low end response to a subwoofer.

[Jon_Logan]

Originally Posted by mrt2

So -6db at 32 HZ, presumably a gradual rolloff above that and a steep rolloff below 32 HZ.

The mechanical/natural rolloff is probably 6db/octave. Yeah, subs aren't efficient at getting to 20Hz. It uses a lot of power, but most speakers, even 18's with a fairly low Fs can get some help getting to 20 with a sub. 12's, 15's, and 18's that are part of a multi way system generally aren't the type of driver optimized for looow bass. If the Fs is very low (like a sub driver would be), the cone will be heavy and it'll have trouble getting up to the midrange crossover point cleanly. Those JBL's are mouthwatering though I'd like to try them. ....but I'd put on a sub. Not because I needed it, but just cause I like the authoritative "thud" of an augmented system. Not just for home theater, ....for two channel critical listening. and not with class-A tube power amps. Instead, SS, so it can get to 20 Hz without massive distortion.

[mrt2]

Originally Posted by BMWCCA

Of course I will defer to your superior knowledge and demonstrated contrarianism and cynicism. But I'm playing my large speakers in a small room. Though feel free to find something to take issue with in that, too.

There seems to be an lot of attitude on this forum lately, ironic considering the slogan "all audio, no attitude."

[dkelley]

Originally Posted by BMWCCA

Of course I will defer to your superior knowledge and demonstrated contrarianism and cynicism. But I'm playing my large speakers in a small room. Though feel free to find something to take issue with in that, too.

wow. Where did THAT come from?

the word of the decade on forums seems to be "contrarianism". if you state something and then someone else disagrees, they're not just a person who disagrees (which is kind of the whole point in discussing things, or studying anything at an advanced university level... you don't just sit and accept everything, you disagree and discuss and learn). Nope, on the web, where people have more guts than they do in person, someone who disagrees is demonstrating "contrarianism", which somehow always manages to come across as if it is derogatory.

LoL, people are funny about audio eh?

anyway, if you're happy with the bass from your speakers then that's great. you're actually not hearing just over half of the lowest octave of some of your music. Is that important? not at all, there's little real music down there. But it does exist in some recordings, and does affect the overall impact of a performance if it's there. So the discussion seems valid to me about the beautiful jbls speakers with 18" woofers going down to 32Hz. I'd say they're great and should do just fine, but anyone who points out that the right true subwoofer would work with those speakers to extend the lowest audible output from your system is quite correct.

But the point of this thread is to discuss if one thinks a sub is important or not. It's not to tell others that they're wrong about their personal satisfaction with their systems.

Right?

cheers,
Don (gradually becoming a volunteer moderator wannabe LoL)

[dkelley]

Originally Posted by Jon_Logan

The mechanical/natural rolloff is probably 6db/octave. Yeah, subs aren't efficient at getting to 20Hz. It uses a lot of power, but most speakers, even 18's with a fairly low Fs can get some help getting to 20 with a sub. 12's, 15's, and 18's that are part of a multi way system generally aren't the type of driver optimized for looow bass. If the Fs is very low (like a sub driver would be), the cone will be heavy and it'll have trouble getting up to the midrange crossover point cleanly. Those JBL's are mouthwatering though I'd like to try them. ....but I'd put on a sub. Not because I needed it, but just cause I like the authoritative "thud" of an augmented system. Not just for home theater, ....for two channel critical listening. and not with class-A tube power amps. Instead, SS, so it can get to 20 Hz without massive distortion.

I like the way you think Jon :-) someone who understands the advantages and disadvantages of different technologies well.

Hell, I owned a pair of hartsfields for years but they were never in the right room so never lived up to their expectations. I also never ran them with good enough gear. But still, they were great EXCEPT in the bass. Think about this - giant high end jbl woofers in HUGE corner installed bass horns (what, 5 feet by 5 feet on the front of the enclosures? something like that).

But I ran them with a powered sub. If I'd had the right room a sub would have been completely pointless. but in my too small rooms with not long enough rigid walls, a sub gave me what I needed.

funny how things can work in less than obvious ways until you think about what is actually happening scientifically :-) that was my experience, I expected a certain sound and got a different sound, the room work the opposite way (size/bass relationships) because the speakers were horns.

cheers,
Don

[BMWCCA]

The original thread's question was "Why Do I Need a Subwoofer...". I'm answering for me. I'm the "I" in my reply. I even said "(for me)". My point was, and I said this applies to my small room, I don't need a sub in my system. There are others who feel this way, too. Here's a quote from the product information describing the design the new Trident HG3 near-field monitors shown at AES:

Separate sub woofers create additional problems by introducing phase cancellations at crossover, and exciting unwanted room nodes - eliminating the advantages of near field monitoring. Separate sub woofer box placement is a hit or miss proposition, guaranteed to cause problems in poorly treated rooms.

And in my room, I'm using even the 4345s as mid-field at best in that I'm not more than ten-feet from them.

I'm also not defending the 2245 simply because I have them. Others use them as dedicated subs. I'm under the impression that they are quite common in iMax theater sound systems as subs. Regardless of quoted specs, if I were looking to replicate the true movie-theater experience in my HT setup, that would seem to be pretty good endorsement for the 2245. They also happen to work quite weil up to my 290Hz crossover point. To quote their designer: ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

What do I know? I'm not an expert and I'm only speaking from my own experience. Everyone's free to disagree. But dogmatic contrarianism for its own sake is just forum bravado.

[dkelley]

just fyi, the comment about sub woofers creating phase cancellations at crossover hasn't been true for decades since all half decent powered subwoofers have continuously variable phase controls to solve that problem. The benefits of subwoofers far outweigh the setup problems. So hopefully that will open your mind to the possibility that, if you ever do want to see if you truly can notice any difference in your speakers by adding a correctly setup subwoofer at the correctly setup frequency range, you can do so without harming the current sound of you great speakers in any way.

I have a feeling that the 2245 might used in a different enclosure from yours in theatres, although I could be wrong of course. I've seen a lot of bass horns in main speakers in theatres, but I'm sure not all of them are horns, so maybe it is exactly as you say. Would be interesting.

[dkelley]

putting my other comments into a new post: :-)

and again, dogmatic contrarianism for it's own sake WOULD be just forum bravado. I haven't seen any dogmatic contrarianism however, although I've seen dogmatic defense about your speakers when, in fact, nobody has done anything but rave about your amazing speakers. Stating that they don't, in fact, constitute a traditional subwoofer due to the cabinet and crossover design, doesn't mean that those drivers aren't capable of amazing sound, amazing bass, and in a dedicated subwoofer setup they could likely get down to 20 Hz I'm sure.

IMHO the people here are being fair, not insulting or contradictory for the sake of being contradictory, and showing scientific pursuit of excellence by trying to improve upon what, so far, may well have proven to be the most amazing speakers in this particular thread.

The topic is about subwoofers and if one's speakers can benefit. The fact is that yes, your speakers can benefit, and no, you don't use or want them because you've found nothing lacking in the bass of your speakers. I too was quite surprised to find that your speakers only get down to 32Hz of useful output. That's really low though, so you wouldn't miss what you're not hearing, and depending on the type of music you're listening to you may not even have content below that which is of any significance, so maybe this is irrelevant to you. But it's interesting all the same that a subwoofer would actually extend the low output of your speakers effectively. Not insulting or intentially taking the other side of an argument for the sake of negotiation and dealing (what I understand "contrarianism" to mean). Just interesting and valuable factual information which, if I were you, I'd be making a mental note about, putting to the back of my head, and then not worrying about ever again because, as you said, your speakers sound great and you've never noticed any lack of bass extension at all.

[Fred Sanford]

Originally Posted by dkelley

The fact is that yes, your speakers can benefit, and no, you don't use or want them because you've found nothing lacking in the bass of your speakers. I too was quite surprised to find that your speakers only get down to 32Hz of useful output. That's really low though, so you wouldn't miss what you're not hearing, and depending on the type of music you're listening to you may not even have content below that which is of any significance, so maybe this is irrelevant to you. But it's interesting all the same that a subwoofer would actually extend the low output of your speakers effectively. Not insulting or intentially taking the other side of an argument for the sake of negotiation and dealing (what I understand "contrarianism" to mean). Just interesting and valuable factual information which, if I were you, I'd be making a mental note about, putting to the back of my head, and then not worrying about ever again because, as you said, your speakers sound great and you've never noticed any lack of bass extension at all.

Actually, there's a discussion worth having about the specs for these speakers as stated- when a flat signal was fed to them, JBL measured them to be ~6dB down at 32Hz. This does not mean that these drivers, in this configuration, cannot give the owner a flat signal to 32Hz or lower with proper positioning, EQ and power amps that have sufficient headroom.

Oh, and he's pretty much like that in person, it's not a forum thing.

je

[dkelley]

LoL, I'll give up then :-)

cheers!
Don

[BMWCCA]

Originally Posted by Fred Sanford

Oh, and he's pretty much like that in person, it's not a forum thing.

And still we have the character enhancement that only electronic communication can bring, both good and bad: the limits of Smilies in articulating our tone, the sanctimony that such depersonalization festers, etc. Again, I was answering for me, which also means what I'm listening to which seldom, if ever, includes the desire to re-create the theater experience in my living room. That's me. I just don't do turbos or sub-woofers, and I admit to being a Luddite.

I'm old enough to have earned that right!

Sometimes when my kids are watching Transformers the whole house shakes and the windows rattle. And other times the whole house shakes and the widows rattle even in-between cuts. Then I know that's a real train going by on real tracks, out in the real world. It's a nice sunny day. I think I'll go for a walk. I believe I've finally shaken the flu.

[dkelley]

Originally Posted by BMWCCA

And still we have the character enhancement that only electronic communication can bring, both good and bad:

Very true 8^D

I admit to being a Luddite.

ah. now THAT explains things :-D

I'm old enough to have earned that right!

The right to have an opinion about your system? of course :-)

I hope you understand that people weren't insultingly criticizing you or your system though, just discussing whether subwoofers would have any audible improvement on the LF extension of your system. Speaking for myself at least, no harm was intended!

Cheers,
Don

...

[Fred Sanford]

Originally Posted by BMWCCA

It's a nice sunny day. I think I'll go for a walk. I believe I've finally shaken the flu. [/SIZE]

You, too? I thought I'd pretty much gotten over it, but today the doc says "walking pneumonia". Fun.

I blame UVA, I was feeling fine 'til I went over into your side of the world (to listen to lots of REALLY large subwoofers!).

je

[BMWCCA]

Originally Posted by Fred Sanford

I blame UVA, I was feeling fine 'til I went over into your side of the world (to listen to lots of REALLY large subwoofers!).

Me, too, on the blaming UVA since I've worked at least four jobs there since your visit.

Could be worse; we could still be missing after that concert. I feel for that girl's friends and parents. I have two twenty-year-old daughters of my own, on their own in NYC. I worry about that kind of incident many a night.



Maybe I just got a little touchy when the first reply to my post includes such an inane comment as; "I have heard powered subs run with much larger (and better) speakers than your JBLs."

I wasn't claiming to own the best of anything, or posting to show off what I do own. I was pointing out that with 18" woofers in my speaker enclosures already, I don't feel the need for a subwoofer. I've seen plenty of systems that cost ten-times and one-hundred-times more than what I paid for mine, some of which are using 8" radiators and calling them woofers. For these I can see why they want subs. The comment simply smacked of cynicism that I felt was undeserved. And WTF do people continue to re-post photo links in the very next post after where they originated?

Now back to the sub-jugation of the forum to the sub-lovers.

[dkelley]

heh heh - I just have to say this, it's the brainstem acting up I guess:

It's not the size that counts, it's how you use it

;-)