Advice on small subwoofer

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bogdan2011

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#1
I need a small subwoofer to go with a pair of tqwt speakers. The woofers have limited xmax and high fs, and although the pipes to help them, they go quite rapidly into distortion.
Is 8 inch a good size for a sub driver if it's going to be used in a typical living room?
What should I look for for tight, precise bass? I don't like that kind of puffy bass that's all over the place and muddies up the music.

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#3
Space wouldn't be such an issue if they're small, but then there's the cost. And instead of 4 subs, I can make a pair of 2-way pipes. The room is bad, but I want to cut the current woofers over 100hz and let the sub reproduce the bass, so it can go louder without distortion.

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#4
bogdan2011 said:
Space wouldn't be such an issue if they're small, but then there's the cost. And instead of 4 subs, I can make a pair of 2-way pipes. The room is bad, but I want to cut the current woofers over 100hz and let the sub reproduce the bass, so it can go louder without distortion.

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Click to expand...

Most important thing when looking for "tight bass" is headroom, the best sounding bass I've found is with (regardless of enclosure design) EQ'ed flat response ~10 dB below what the design was meant to handle. Distortion due to cone excursion and turbulence (if ported) should be quite low and output should be linear at this point.

As to what design/driver best accomplishes that goal -> for me it's a folded horn. For others small sealed subwoofers fit the bill. It would be easier if fixed size and cost limits were imposed as that rules out a good portion of designs. Sometimes a couple 6.5 inch drivers in tapped horns is enough, sometimes a 12 inch loaded folded horn that takes up half the room (figuratively) is needed - depends on how loud you listen.

Best of luck.

Easy solution: put a 18 inch stereo integrity woofer in 4 cu ft sealed EQ'ed flat.
 
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#5
My house would fall apart with that!😀
I've always thought that foam surounds and high Qts give that sort of car audio bass, which I never liked.
Anyway, some candidates:

Silver Flute W20RC38/ 8 inch

Sensitivity 93.7 dB
Power 100 watts
Fs 31.0 Hz
Qms 1.51
Qes 0.27
Qts 0.23
Vas 72.3 Ltrs
Mms 23.7 g
Cms 1111.3 mM/N
Sd 0.0214 M2
BL 7.9 TM
X-max 5 mm

Beyma 8WOOFER-P V2/ 8 inch

Fs 35 Hz
Re 5.8 ohm
Qms 2.72
Qes 0.62
Qts 0.50
Vas 59 l
Cms 858.3 µm / N
Rms 1.95 kg / s
Efficiency % 0.39
Sd 0.022 m²
Xmax 4.5 mm
Vd 100 cm³

Beyma 10BR60V2/ 10 inch

Fs 31 Hz
Re 6.5 ohm
Qms 3.29
Qes 0.55
Qts 0.47
Vas 108.2 l
Cms 536 µm / N
Rms 2.89 kg / s
Efficiency % 0.57
Sd 0.038 m²
Xmax 6.5 mm
Vd 240 cm³

Beyma SM-110N/ 10 inch

Fs 43 Hz
Re 6.2 ohm
Qms 7.88
Qes 0.37
Qts 0.35
Vas 65 l
Cms 368 µm / N
Rms 1.3 kg / s
Efficiency % 1.4 Sd 0.0355 m²
Xmax 4 mm
Vd 141 cm³

Beyma 12BR70/ 12 inch

Fs 31 Hz
Re 5.6 ohm
Qms 4.44
Qes 0.56
Qts 0.50
Vas 142 l
Cms 345 µm / N Rms 3.3 kg / s
Efficiency % 0.76
Sd 0.054 m²
Xmax 8 mm
Vd 340 cm³

Apart from the Silver Flute and the 10 inch beyma with cloth surround, they're suited for sealed enclosures. Not sure about which one would work in a horn, but I'd keep the size as small as possible.
 
#7
Why not put 2 in each box?? 2 8"S that could produce great output.
Maybe 4 of these?? http://www.parts-express.com/dayton-audio-sd215a-88-8-dvc-subwoofer--295-484

Or put 4-5 in a single large box.

I personally prefer subs 10"-18" . They eat small subs for breakfast

Try this a single one $affordable performance.
http://www.parts-express.com/dayton-audio-ts400d-4-15-titanic-mk-4-subwoofer-4-ohm--295-405

Pricey $600 option. This will outperform 90% of other subs http://stereointegrity.com/product/hst18-18-subwoofer/
King of king of subs.
 
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#9
The Daytons look similar in specs, but the advantage the Beymas have is that I can buy them directly from a seller, they're easily available here.
The other ones are quite expensive for my budget.
I'll probably choose a 10-12 inch driver afterall, bigger is better anyway. But I want to ask if 12 inch is too large for a T-line enclosure. I heard they're better than sealed ones.
 
#10
bogdan2011 said:
I need a small subwoofer to go with a pair of tqwt speakers. The woofers have limited xmax and high fs, and although the pipes to help them, they go quite rapidly into distortion.
Is 8 inch a good size for a sub driver if it's going to be used in a typical living room?
What should I look for for tight, precise bass? I don't like that kind of puffy bass that's all over the place and muddies up the music.................
Click to expand...
Two 8inchers are what you would get with a pair of ordinary 2way speakers.
If you want to augment the bass available from TWO 8" drivers, you do NOT replace them with ONE 8" driver.

Sd of one dedicated bass only speaker would need to be around 11" to 12", just to match the two 2ways.
Start with a 15" and preferably two or three of them.
Or go with a very long Xmax 12" and again preferably two or three of them.
 
#14
Kingnoob said:
Why not put 2 in each box?? 2 8"S that could produce great output.
Maybe 4 of these?? Dayton Audio SD215A-88 8" DVC Subwoofer

Or put 4-5 in a single large box.

I personally prefer subs 10"-18" . They eat small subs for breakfast

Try this a single one $affordable performance.
Dayton Audio TS400D-4 15" Titanic Mk 4 Subwoofer 4 Ohm

Pricey $600 option. This will outperform 90% of other subs HST18 18″ Subwoofer | Stereo Integrity
King of king of subs.
Click to expand...


I've built two boxes with this driver (the dayton audio SD215A-88) for my GF. These are good if you don't exept too much from them! my boxes had to be small, very small! so I don't think I can get the real deep bass out of them! They are just enough for listening music ( you can listen dubstep, of course) and for movies but they won't go down to 20hz, maybe a real 30hz but not really better than that! if you want plans just ask 🙂

For me, I've built a single 15" subwoofer and this rock! the woofer is a GOOD no name subwoofer! no flapping and by hear, I this Fs is about 25-30hz but I'm not sure it's hard to say! the box is approximatly 100lts (don't remember) and I get more than what I paid for! scrap wood, 40$ driver, total cost maybe 55$ and it sound damm good! It's not to big, maybe a 15 could be good for you too 🙂
 
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#16
If you've got power but no budget, I'd get a JBL GTO1214. I run two in a 16" sealed cube. Needs a lot of EQ to get low, but its a lot of bass from a tiny box. Distortion does set in when power is applied, though - they only use a simple ferrite motor - no demodulating rings etc.

Next size up would be an undersized ported box. I built 80L tuned to 18Hz, giving a response that slopes down to 18Hz before falling off a cliff. You can EQ to get flat to port tuning, though, which was impressive out of that box. In hindsight, I should've kept that box and gone isobaric.

Bigger again would be a low compression ratio tapped horn. The Qts on the GTO1214 is just a bit too high to be stuffed into a small TH. Larger THs (see the Kraken) are reputed to perform very well with these drivers, though.

Chris
 
#17
TBTL said:
How is subwoofer sounds is usually dominated by the room. Using multiple subwoofers and a parametric equalizer reduces the effect of the room. Do you have space for 4 small subwoofers?
Click to expand...

I have always sought the ability to reach, hear, and feel the lowest of lows and thought that one sub (irrelevant of diameter) that really cannot put out say 14Hz in a meaningful/audible way could be augmented with more of them and then the one signal sent to all four (or more) could be DSP equalized such that everything up the spectrum from 14Hz wouldn't sound much too loud. Basically "cheat" to get that ruler flat response from say 14 to 100Hz.

But, I am familiar with wave cancellation and how specific frequencies from just one sub can meet the room's cancellation size and just "disappear from audibility." Yes, a new placement helps.

However, with the four subs in mind, let's say each is in a corner of the room (1/8th space), of sealed design, and firing directly towards the next clockwise sub (ie the pressure waves are fired along the wall). If the four subs were labeled C1, C2, C3, and C4, then C1 would fire at C2, C2 at C3, and so on. Having them all fire towards the center of the room would likely cause cancellation waves quite easily.

The goal, as I see it in my mind, seeing the air as a fluid, is to create a bubbling cauldron of sound pressure throughout the volume of the room (and the corners would likely still feel the loudest of course - nothing really counteracts that fact).

OR, could each of the four subs be sent a slightly different frequency? Say C1 gets the original signal, the DSP downadjusts that signal by 1/3 hertz and sends to C2, C3 gets the opposite at 1/3 hertz higher, and then C3 gets something nearby too.

Would that be enough to prevent wave cancellation YET not be noticeable enough in frequency change that I would say "That sounds 'off' or that sounds 'like mud'?"

My most effective sub setup was two in each corner against the room's back wall and in 1/8th space. Me and my long couch were located against that same back wall, centered. The subs would fire at about 22 degrees inward into the room BUT each of their slot type vents would fire directly along the wall towards me from each directlion. They were about four feet tall, three feet wide, and between two feet and four inches in depth (a modified trapezoid?). It did work extremely well. Seen across the room about 12 feet away, it was either the TV screen's image that was vibrating to the bass (ie the whole heavy TV) or my optic nerve (grin).
 
#18
My current setup is placed in a perfectly square room (4x4 meters). The sound of the room is awful, with bass in odd places like the side of the speakers (and of course the corners), but lacking where it's needed, in the listening position. The good thing is that it's temporary, since I'll move it to the living room when it will be ready. That room is a bit better acoustically (it's about 5x3 mt). A room built specifically for music would be the best thing, but unfortunately it's not possible at the moment. I don't seek to repair the acoustics of the room by adding subs, but I look for two main advantages: more bass even at low levels and less distortion from the mid-woofers. So it's more of a "sound reinforcement woofer" rather than touching the sub frequencies.
 
#19
I recomend to read the white paper from Harman

http://www.harman.com/EN-US/OurCompany/Innovation/Documents/White Papers/multsubs.pdf

And use the room simulator of REW
REW - Room EQ Wizard Room Acoustics Software

Then you see how low frequencys your room will support and at what level. If you are lucky and have a roomnode at 30 hz you could have a small sub else you maybe need more volume displacement of air.
Or you might have a zero at 30 hz and you could have all the power you want and still not hear anyting at 30 Hz.

I have good experience with 4 boxes of 12 inch drivere with slave. Long x max, small box. (Actually 30cm diameter tube)

Plays very loud and clean in 20 square meter room if placed propperly. For me the room can be slow, not the sub (if made propperly).

I also think it is a good idea to offload the main speakers from the lowest bass to generate less distortion where it can be heard (500 - 4000hz. A speaker will distort at higher frequencies when the membrane displacement because off lower frequencies is large enough, eg approaching x linear)

God luck
 
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