How Much Bass Is Enough???

[BHTX]

my house's stick built/floating floor construction limits usable sub gain BW.

I remember when I was much younger, I was in an older house (built in 1950) with a peer and beam foundation like that. Although I suppose it wouldn't be considered a good thing for 'hi-fidelity' as far as keeping things neutral, it did add quite a bit to the sense of feeling when using even lower quality (although over priced, like $500 each) subwoofers from rip-off hifi shops at even the most moderate levels. Anything from under 20Hz to over 40Hz at even relatively low volume could easily be felt though your body. It wasn't a lot, certainly nothing overbearing or annoying, but added just enough realism at times during movies to perhaps make them just a tad bit more enjoyable, and I often found it beneficial during music as well. It was actually so subtle that the average person wouldn't notice it directly, yet it would add to the experience. Like free ButtKickers.. but much more subtle, and perhaps more realistic. Booming on the floor with the heel of your foot would seem to resonate most rooms at around 35 Hz or so. My bedroom there when I was a kid was the best . To be honest, I've actually missed it ever since. I do have a pair of ButtKickers that have been going to waste for years. I still plan on building a simple platform, once I get better seating in here (that both the couch and my feet can rest on), in an attempt to obtain similar effects. As expected though, that old house had severe problems with rattling, even at the very farthest end of the house away from the subwoofers.

 

[Moondog55]

Hi Tinitus !!

 

[GM]

Yeah, mine was finished in March 1952 and its resonances do make LF recordings seem more realistic, especially from vinyl where it's next to impossible to completely isolate the TT. Even real thunder has about the same tactile 'feel' indoors as it does outside, but it's no good for true infrasonic BW at any level above ~110 dB as the near petrified Yellow Pine framing starts to shake the drywall seams apart and in the case of the original ceiling's really crummy 3/8" drywall, well, I was 'Chicken Little' late one night during a sustained low B at >120 dB when the 'sky' fell down on me along with ~12" of blown in insulation.

It was tempting at the time to recover the entire room in a couple of layers of overlapping MDF, but the county led us to believe that the whole area would be rezoned in the not too distant future, so I went the cheapest route, but now it's looking like 2014 at the earliest, so wish I had as that level of bass reproduction so totally spoiled me for anything less.

GM

 

[Moondog55]

Tinitus I thought the feeling here was that it was/is impossible to have too much bass as long as the mids and tweeters could keepup.
It's not as if I am going to play music at these insane levels as a norm, but I agree with the sentiment that if I want to I should be able to with out compression and with as much clarity as the listening environment allows
I can make the house shake now using those CerwinVega 124's in the tiny sealed box, although thats the consrtuction of the house (LOOSE) I just want an octave deeper at the same level

 

[GM]

There's not, only a point of rapidly diminishing returns which use to be at ~25% of a driver's rated power, but with the improvement in materials technology in the last decade it may be a higher number now based on actual thermal power compression measurements.

GM

 

[CLS]

Talking about waveguided OB, I'm not sure if anybody out there has played the same simulation game....

Once I made some simple simulations in hornresp for a giant "horn" with 6*18"ers.

I played with the throat size and horn lengths a bit (with the biggest mouth allowed of course) and found in such cone area and big throat, the 'horn' length need not be long to produce low bass. It can be as short as 60cm to support the bottom octave. Amazing!

If one can merge the speakers into the room decor, I think it can be done with not much space. Eventually the big bass 'horn' is just like a tilt-in wall and takes only a little floor area.

 

[GM]

Right, add a driver and you can shorten the horn up to where the new throat area is, but they are still pretty big to go low. Here's a Westrex with four 15" and JBL 300 Hz horn:

Gm

 

[BHTX]

^ LOL nice! Odd though, I could have sworn I saw another massive loudspeaker in that same exact room.. 2 giant woofers of some crazy size and a big horn in between them. I might be wrong though..

 

[tinitus]

Hi Tinitus !!

Hi Moondog

Yeah, Im no better myself

My next design will probably be an 18"(Fane?) with 8"(B&C?) and CD/horn(B&C/18sound?)
Maybe some day I will have a sub with multiple drivers ... at the moment I think a sub is the only place where multiple drivers makes sense, mainly because of the low SPL of subdrivers and Xmax issues

But I have lived with a speaker with too much bass, or rather too little midrange, which was quite annoying ... problem solved though
I believe that articulated and well defined bass is absolutely crutial ... in this respect I think that the suggested waveguided woofers might shine
Crossover, phase, timing have a good deal to say in this
Too much is bad and too little is not good either ... the just right amount of bass is not so easy to achieve

 

[Moondog55]

Tinitus I am supposing here that bi/ tri amping will help the balance issues.
I think it's time I merged two projects and built the "Tardis" woofer box, just to hear the difference in sound cardioid bass brings to the room.
Has any-one here experimented with cardioid mids?? Rather than build a flat baffle I am thinking of experimenting with a rear firing mid opposite the tweeter in the MTM, a sealed box would allow just a little more power handling and Rabbitz has a pair of Vifa P11's on eB** at the moment, and putting a small box inside the bigger one stiffens things up very nicely

 

[tinitus]

Tinitus I am supposing here that bi/ tri amping will help the balance issues.

Sure, bi/tri amping could be an option, allthough my experience is not so good, at the time I tried it the coherence went down the drain, I am not certain what but something went completely wrong, my speakers were suddenly not so exstremely well balanced ... may have to work on that issue

 

[navin]

hmmm, how much bass is enough?

Both OB and horn are, may I say, "quick", but in so differnt ways. One is like wind, the other is like a rock hammering the ground. So, even at the frequency range both are good at, say, 40~80Hz, and at same SPL, they still sound very different.

I'd say, I can live with OB with music for most of the time, but I surely admire the "WOW" factor of a proper horn.

Man! why can't I have both

I feel your pain. What about TL? I once heard a Fried TL that was superb.

 

[Moondog55]

My experience with bi-amping has been positive, but so far I have only been using it on the transition from bass to mid, I am using a Behringer CX 2310 and while it may not be the best it is ertainly cost effective and I find mids are much cleaner and clearer using this unit, I also cross very low usually 120/ 150 Hz, and to date I have not tried a Tri-amped system although I have a CX 3-way crossover sitting here I have not yet used it in a 3-way setting.
I find the ability to balance or boost levels handy

 

[tinitus]

My experience with bi-amping has been positive

I find the ability to balance or boost levels handy

As I hope it will be next time I try again

 

[Moondog55]

These drivers seem to be both reasonable in performance and price,

http://www.audiomarketplace.com.au/...product_id,3/option,com_virtuemart/Itemid,49/

Has any-one here used them OB as they are designed to be used and want to comment on them??
No waterfall plots or impedance /SPL graphs but I could probably afford 4 of these and a sub if needed, would 4 be enough??

 

[BHTX]

I haven't used them, but my guess would be that they're far too small and inefficient, and Qts isn't high enough, while Fs is too low.

For an example of a driver that works well for OB down to 40 Hz, take a look at the Eminence Alpha-15A. Problem with that is the lack of Xmax. Problem with using 2 or 4 per side is that your mids/highs would be too high up on the baffle, lol.

If there were similar 12's out there, I'd imagine you wouldn't find anything that would go quite as low as the Alpha, and they'd probably have a lower Qts and sensitivity. I have yet to see good enough 12 that's readily available. On the other hand, Magnatar's last OB project he posted a while back looks like a good compromise. But I don't think you can get them in 16 ohms anymore, or even at all.

 

[Moondog55]

Inefficient is right but I was under the impression that Qts of 0.7 was about right for OB, what have I missed??
The Eminence Beta 15 is avaliable at a reasonable price
Power handling: 300 watts RMS
VCdia: 2"
Le: 1.10 mH
Impedance: 8 ohms
Re: 6.32 ohms
Frequency range: 45-3,700 Hz
Magnet weight: 34 oz.
Fs: 35 Hz
SPL: 98.2 dB 1W/1m
Vas: 11.8 cu. ft.
Qms: 8.10
Qes: 0.63
Qts: 0.58
Xmax: 4.0 mm
I would have thought X-max was far too low for OB use so I'd need 4 of them, quite efficient though, and they are on sale at $100-each, but then I'd need an efficient midrange to go with them, although I could pull my party speakers apart and use the old Tandy/RadioShack 10's as midrange

 

[BHTX]

Inefficient is right but I was under the impression that Qts of 0.7 was about right for OB, what have I missed??

Qts of .7 is about right for IB, not OB. Two completely different things. I don't know why the majority of people even on this forum seem to completely miss that fact. That's likely the reason you've been misinformed.

With open baffle, you have to make up for the dipole cancellation. With infinite baffle, there isn't any. For IB, I would say that a Qts of .6-.7 is probably ideal in most circumstances. For OB, expect to have a Qts of well over 1 to avoid having to boost the low frequencies with an EQ.

The Beta 15 you mention.. its Qts is way too low, you'd have to give it loads of EQ to get it sounding decent, and 4mm Xmax isn't enough for all that boosting. For a ripole or something like that, it might work well.. but not for use on a simple flat baffle.

I've tried 4 15's with a Qts of about .7 and xmax of 6mm, and it wasn't ANYWHERE near high enough.. had to boost it a ton down low, and this was in a W frame. Since then, I've tried a cheapo 15 with a Qts of about 1.2 on a flat baffle, and it worked pretty well.

Download Xbaffle.xls and model a few. It'll help give you an idea of what will work best.

 

[Moondog55]

Just modelled the Eminence Nice pro midbass, but no way a subwoofer/infrawoofer.

 

[tinitus]

That DPL-10 is actually down to 65USD at DiyCable.com

I dont think the Qts is of concern but rather the very low SPL
Furthermore its a subdriver and should probably not be used high
Below 100hz it will probably be more linear than a pro driver

I have been thinking about using such a driver in an OB monosub with multiple units ... but its a lot of drivers to have on your hands if it doesnt work