High efficiency 8-10 inch woofer for OB

[maggiesnmacs]

I'm building an open baffle speaker with 4 woofers playing from hopefully 40-50hz up to about 400-500hz. So I need an fs and q that gives good response down to at least 50hz and probably at least 4mm xmax to stay linear up to reasonable volume. I'm hoping for it to be in the 50-60 dollar range but would be willing to pay up around 100 a driver, but otherwise just want the highest sensitivity I can find. 93db/w/m would be good but as low as 88 or 89db/w/m would work. I really at the end want as much sensitivity as possible without sacrificing quality and having at a minimum 60hz -6db but 50hz would be better and 40hz would be phenomenal.

Some that I found are this scanspeak

https://www.madisoundspeakerstore.c...very-26w/8534g-10-aluminum-cone-woofer-8-ohm/

Looks nice but the 89db is sort of low.

This Dayton PA driver is cool and probably my favorite as far as specs but I'm not sure if it's of lower quality for home audio since it's designed for PA applications.

Dayton Audio PA255-8 10" Pro Woofer

Kinda same idea for this eminence woofer of not being sure if it's good quality

Eminence Alpha-10A 10" Guitar/PA Driver

I mainly just found it hard to find any drivers that were designed for home audio that fit the bill of high efficiency since most are designed to target low frequencies. Is there any truth to my pre-determined bias against drivers designed for PA?

 

[Pano]

PA drivers are often better than "home" types, so no need to be biased.

8-10 is small for an OB woofer. Are you using 4 per side? That would help. The hard part about OB is the bass loss. You can easily lose 10dB just because of the open baffle. You'll want to choose your drivers carefully and know that you need to deal with the bass loss and the tonal balance tilt.

OB is different enough from box speakers that it can take some time to learn.

 

[Face]

Some PA drivers are perfectly acceptable for home use. Just like home drivers, you'll have to wade through the turds.

 

[maggiesnmacs]

I am gonna use 4 per side and that's why I was expecting 60hz but hoping for 40 or 50. I'm using a separate sealed sub and therefore don't really need any deep response. And with the mindsp and hopefully a higher q woofer Ill control low frequency excursion.

So I think my gut is telling me to go with the Dayton pa255-8 then. Anything against that particular woofer? With a 50hz fs and .6Q I should be able to get good response to 50hz with eqing

 

[LineSource]

--There are several 12" and 15" dipole woofers that do not require equalization if you can accept the width.
--With a HIGH power amp, you can equalize a large Xmax 10" HUSKY (sub)woofer.

--Similar to the Dayton PA255
10" Faital 10FE200
Fs = 55Hz
Qts = 0.7
~95db @2.83V
Xmax = 4.7mm
$53

-------------
Example: Acoustic Elegance TD10D
--A 10" designed for dipole bass will have low efficiency as these T/S show.
- wire four in parallel for 4-ohm load and you have ~98db/watt efficiency

DIPOLE10 (coils in series)
Fs: 25.9Hz
Qms: 11.0
Qes: 0.73
Qts: 0.68
Vas: 118 Liters
Cms: 0.7mm/N
Mms: 54.6 grams
Sd: 345 cm2
Rms: 0.81Kg/S
Bl: 12.2T/m
Re: 12.3 ohms
Z: 16ohms
Le: 0.15mH
Pe(max): 200Watts
1WSpl: 87dB
Xmax: 12mm

 

[nigelwright7557]

Fane 10-300pro.
Good xmax for high power output.

 

[Pano]

4x10" woofer per side would give you more cone area than a single 18", which is good. But I think I'd still go with the 18". Or do a 21", if you dare.
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-143.html#post4702952

Would the Dayton PA460-8 18" Pro Woofer do the trick for you? It has a medium low Q, but is efficient enough so you can afford to trade away some with EQ. Would take up a little less baffle space than four tens.

 

[maggiesnmacs]

I think I'm gonna stick with the 4 x 10inch max width. Since I think I can achieve my 50hz goal pretty well with that, I'd personally prefer the sleaker look and especially the smaller footprint in my 200 Sq ft. Living room...

I drew out what I want to box to look like and it's something like this but with the 4 woofers a little closer together. Scale is 2 inches per centimeter and the baffles are 48x12 inches

This size baffle in edge gives me this response

The dipole peak is at 600hz which is a good spot for my crossover to my 3 inch midrange. And it is -12db at 50hz which means the 4 woofers in OB would have the same excursion at 50hz for the same output as 1 woofer in a sealed box. From previous experience 1 10 inch per side in a sealed enclosure can put out good clean output down to 50hz and if I need moreally headroom I can always bump the crossover up to 60hz.

 

[MR Overclock]

I would actually recomend that you get a larger speaker than use multiple small speakers.

I reckon a single 15inch would beat 4X 10inches in sound quality and volume

Would one have tried a 10Inch VS 15Inch would instantly know that the big one has a much better low freq response and sound much better. much much better quality in mid lows

 

[maggiesnmacs]

Right a 10 vs a 15 the 15 will definitely sound better. But 4 of them vs a single 15, well first off a 15 has 2.25x the surface area and probably about 1.5x the excursion so about 3x the volume displacement. Then there is a little improvement from the wider baffle, which would account to pushing the dipole peak frequency down by a factor of 1.5 which would also improve the low frequency effienceny by a factor of about 4db. So all in all 4 10 inches would have a similar response to a single 15. But I also end up with a 99db/w/m setup that would be hard to compete with with a single 15 and I really like the sleek look of 4 10's and the smaller footprint so I think I'm going to stick with the 4 10's for me.

 

[MR Overclock]

I tried a propper 8 Inch push pull set up, with comparison to one 8 inch, there isn't much or any. Max volume I can crank out of them is only sligthly more with duall 8 inches.

Thats Why I had recomned you to get a signle bigg speaker instead

 

[Jim Griffin]

As a mid-range driver (175 to 700 Hz in my case) I have used the FaitalPRO 10PR300 as an open baffle driver. Very good vocals and excellent high efficiency response in my project. Neo magnet loading and light weight but at a price of about $200 each though.

http://www.parts-express.com/pedocs/specs/294-1203-faitalpro-10pr300-8-specifications.pdf

For my woofer coverage I suggest a 15 or 18" diameter driver for an open baffle. A 10" driver is a good open baffle mid range but you need a larger displacement/cone size for coverage below 100 Hz.

 

[John Busch]

10" OB woofer issue

Have done similar before, but with 4 each 12" per side, passive crossover 2 way. I think your PA225 proposal is a winner for several reasons.

Don't let the "PA" issue bother you. This is a good woofer with a faraday ring, a big motor, bump plate, larger SD than most 10" and overall, WAY more durable than just about any "hi-fi" 10". And this is all at a bargain under $42.00 each delivered! Break up is high enough that at your intended crossover frequency it will not be an issue.

Also it really is 92 db/watt with a 5 mm xmax. Nice combo given your stated design goals. Most hi-fi woofers with a similar Xmax are more like 88 db/watt.

Keep in mind that true OB efficiency below F peak is set by the effective baffle width. You have to either equalize electronically or trade the drivers electrical efficiency away passively to realize a flat acoustic response below F peak.

So, you need as much displacement as possible, but for a reasonable cost.

As Pano said, 4 each 10" drivers will give you a combined radiating area greater than any 18". And an 18" with a 5 MM xmax is plenty for most home OB systems. Especially when you factor in your 40-50 Hz cut off.

Just my $0.02 worth! Please let us know what you decide.

 

[zmyrna]

I would not use multiple drivers over 100Hz

 

[maggiesnmacs]

I would not use multiple drivers over 100Hz

Curious, what is your justification for this? Interference? The effective "width" of the driver is 40 inches, which doesn't lead to any reasonable interference up to 400hz, and even then that's only in the vertical axis.

 

[Scott L]

--There are several 12" and 15" dipole woofers that do not require equalization if you can accept the width.

I have read this claim before. How much width are you talking about ?
I can't wrap my head around a di-pole bass system, or open baffle, that does not suffer from some degree of front-to-back wave cancellation.

I had always thought the baffle width sets up the frequency limit, and then the response falls 6db/octave below that, until driver resonance is reached, at which point in time it falls an additional 12, for a total of 18db/octave.

A driver Qts of .7 is pretty much already maximally flat, provided the baffle width prevents cancellation. Since it's an open baffle, there is no such air load to raise the system Q.

I have heard an open baffle attempt with drivers having Qts much higher, say 1.2 for example, and this thing exhibited some sort of boooooom somewhere in it's operating range, somewhere just above where the cancellation wins.

There seems to be quite the following and popularity of "OB Bass", but I can not, for the life of me, figure out what the driving force to this is (?)
I suppose one strong possibility is, there exists a preponderance of really bad sounding boxes out there in DIY land.

 

[maggiesnmacs]

I also wonder about the claims of not needing eq when using woofers of .7q. And you are right that the width sets up the frequency. I think that when people say eq isn't necessary that they just mean the roll off that you end up with is acceptable, but not to me...I'm going to be using eq so I just need the sensitivity and excursion.

It can be done though without eq if the right q woofer is used and it is all carefully set up. Here is an example I have seen

https://www.google.com/url?sa=t&sou...xl_jaSLPSG7HNvkpg&sig2=_j9B6A4kheRaL9kmBfRLow

 

[Pano]

Martin King uses a small magnet high Q woofer and a wide baffle.
When you said 4x10" I imagined a square arrangement. A narrow line like that is going to limit you.

As John Busch can tell you, wider baffles sound more dynamic. You might be able to cheat some with side wings.