Which Woofer for 10P WAW?

Howdy all.

I’m planning a Woofer Assisted Widerange project and would appreciate some thoughts.

The wideband is an Alpair 10p. Is there any rule of thumb regarding size of woofer to suit this? The plan is to cross over to a woofer at maybe 250Hz give or take, and then to hand off to servo subs in the 50-80Hz range.

I do like the impact of larger woofers, but would smaller woofers have greater finesse? Finesse is more important (to me) than impact, if there has to be a trade off.

Options are to use the 15” Faital Pro 15PR400, or potentially to sell those and use either single or double 8” Peerless HDS Nomex drivers per side. Another option is a pair of Seas Excel W17CY001 per side. Enclosures will all be sealed, actively driven and XO’d/EQ’d with MiniDSP.

If using the 15”, the woofer will be side mounted to keep the enclosure narrowing. If using smaller woofers, they will likely be front mounted.

Any thoughts appreciated.

Cheers,

Matt.
 
frugal-phile™
Joined 2001
Paid Member
Matt,

There are a huge range of potential drivers.

Given that XO, a response up to near 2kHz is desirable. With a nice smooth roll-off.

And, any time you can get 2 woofers and mount them push-push you make huge gains in cabinet loading.

Then you have to factor in:
Size? WAF?
Budget?
What is easily available?
Room location?
Support kit (do you have a spare amp for bass duties)? If we assume you are going active. And the skills to design an XO that low if you want to try passive (adds more constraints to the woofers, but is doable)?

We know that you prefer fitness over absoltr response. Other preferences.

1 servo sub or 2?
That having a sub means that what you really want is a FR coupler (couple the FR/midTweeter to subwoofers).

We haven’t done a WAW with A10p, but i do have a couple schemes for them. One an OB w 4x10” helpers, and another a modular setup with 2 A12pw miniOnkens sandwhiching A10p (or A10.3, A7.3/ms, A6.2, A5.2/3. A10p is the goto if you enjoy vintage top, don’t want to have any excuses for playing loud, or are using a small amplifier (often SE) up top.

The Halcyons uses A10p, 2xSB 6.5” bass drivers in a TL.

Curt Campbell's Halcyon build thread
Has anybody built, or even heard the Halcyon speakers by Curt Campbell?

Our WAW have used A7.3eN and FF85wKeN (and a couple earlier sets w FF85KeN). In those we used 6.5”-7” midwoofers. The 6.5” MTMs have a 250 Hz XO, the 7” 180 Hz. The 7” goes to 1.7kHz, the others all usable to twice that. I have imagined turning these into 3-ways by adding multiple DSP controlled subwoofers to do <40 and fill in for the worst room whoops above that for an octave, ocatave & a half.

We have used the 4” version of your mentioned Peerless in an ML-TL (2x) or an ML-Voigt (4x). I haven’t looked at what the 8” does. Sealed F6 near the max you want to run the subs would be good. We do prefer the Silver FLute W14 for these small WAW, largely becaus ewe can get better LF performance with the W14 less than half the price of the 4” Peerless (but a bigger box — always a trade-off somewhere).

With subs, i suggest that the Faital is way too big. And the SEAS may be too ringy up top (likely at least partially fixable). And pricey too?

dave
 
Hi Dave, thanks for the detailed response.

A few answers:

Dual servo subs are being used, one per side, close to the mains.

Size - unsure whether to put them on top of the subs or floor stand, so call it up to maybe 60 litres for the bass driver (s)

Seas drivers are not Magnesium but fibreglass, I have them in the shed sitting in a cupboard:
http://www.seas.no/images/stories/vintage/pdfdataheet/e002.pdf

Amp: I have 3 available for the top, ACA 1.6, Pass F5 clone, and a 1.8wpc SET. Bass drivers would use either the F5 or other amps I have lying around.

WAF is definitely desirable heh heh

I do have skills and test equipment to do passive, but active is so much easier. However, I’d be interested in the required woofer voltage sensitivity that would match up the the 10P.


I’d be happy to run woofers in moderate sized sealed enclosures and eq to taste. Would probable aim for a natural Q of 0.7 and then EQ as required.

Cheers,

Matt.
 
frugal-phile™
Joined 2001
Paid Member
SB Acoustics SB34NRX75-16[/URL] , 16 ohm 12" Woofers work along with the A10p, keeping with an easy 8 ohm load and ~ 89db sensitivity WAW speaker system?

Sensitivity wise just about right. 3dB for doubling the cone size another 3dB for the parallel connection. Woofers about 3 dB more than teh FR. A little weak as you go up in frequency but i’d say workable.

But a passive XO is hard, even harder if you are trying to maintain a flat impedance. And if you are trying to keep it 1st order even harder. And often more expensive than active. Especially if you end up with extra parts after experimenting and fine tuned.

Active with a set of speakers designed for a PLLXO and the cost of XO approaches zero with no “electronics” haze (1xR, 2xC parts per side), leaving only the need for an amp for the woofers. Score an old integrated, put together one of the inexpensive Class D amps, or a chipamp. How many people already have an extra amp lying around? And there will soon be 2 suitable Nelson Pass XOs @ the diyAudio store.

The halcyon has a passive XO as have 3 of our WAW (1 NLA, 2 current).

dave
 
frugal-phile™
Joined 2001
Paid Member
Seas drivers are not Magnesium but fibreglass, I have them in the shed sitting in a cupboard:

Top as bad than i expected, lots of room to try to knock the top down 10dB (some puzzlekoat/modpodge.

2 in a damped box of about 35 litres or so, with a 2nd order butterworth filter at 60 Hz.

The cone mass is fairly heavy, even 3 or 4 coats of thinned puzzlecoat will only add a small relative mass to the cone, Fs goes down but the other parameters tend to change in directions that compensate. Sensitivity will also drop, but not by enuff to get them wher ethey need to be (unles syou pull tham way out into the room (or prefer exagerrated bass — nothing wrong w that).

Amp: I have 3 available for the top, ACA 1.6, Pass F5 clone, and a 1.8wpc SET. Bass drivers would use either the F5 or other amps I have lying around.

So no issue with amps. Lots to try. The 2 small SE amps should be interesting.

WAF is definitely desirable

At 35 litres a slim stand w a woofer on either side can have its dimensions dialed in to fir under whatever you put the A10p into.

I’d be interested in the required woofer voltage sensitivity that would match up the the 10P.

About 93 dB.

Would probable aim for a natural Q of 0.7 and then EQ as required.

EQ gives a bit more flexibility if the box would like to be smaller.

dave
 
frugal-phile™
Joined 2001
Paid Member
Here is a 1st pass. Near golden ratio bass enclosure. A10p in an aperiodic TL.

It is too low, one can give up enuff depth to push the height up the desired amount — you don’t want to go narrower for the sake of the A10p. Tha shortens the TL, but you probably want to fold the line into a rectangular box (terminus out the front).

attachment.php


So at a guess 250 wide x 1000 high by whatever the decrease in depth needed to account for the greater height.

Subs should go wherever they best counter room resonances. Within a 1/4 wavelength at 60 Hz (say a half metre).

dave

dave
 

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Thanks for the detailed drawings Dave!

The Peerless 8” driver appears to fit into a reasonably small sealed enclosure, would it be possible to put a pair of those into the first drawing you posted, in place of the Seas Excel? ? I rather like the sloped top of the first diagram :) mounting depth and internal enclosure. volume would work for dual sealed and also single or dual vented.

Peerless by Tymphany 830869 8" Nomex Cone HDS Woofer

Cheers,

Matt
 
I do use the 10M (the metallic cone variation, but for the rest almost the same) with an Scanspeak 26W/8534G00 in a 77L sealed cabinet, and that works very well. I did also build the same 77L cabinet with an SB34NRX75-6 driver for someone wich even works better with this driver. But both enclosures are bigger than you spec (can you stretch it a bit?). In both cases i use a passive serial 1st order crossover at 250Hz (which is expensive to build, as you need a few big inductors and caps). Both are powered with a Prima Luna tube amp amp (32w in my case) wich is enough to go very loud in my living room (8x6x2.5m). With a set you won't be able to drive this, so i would use a seperate sub amp that gives at least 20w with this, and an active crossover (analog or dsp).
 
I can highly recommend the RS225-8. It is unique in that it is wide and and very flat. The breakup doesn’t happen until 7kHz so you can use a first order XO and it sounds great.

10F/8424 & RS225-8 FAST / WAW Ref Monitor

You won’t find a more expensive driver from ScanSpeak, SB Acoustics, Tang Band, etc that can do what this $60 driver does. Really in its own class.
 
I can highly recommend the RS225-8. It is unique in that it is wide and and very flat. The breakup doesn’t happen until 7kHz so you can use a first order XO and it sounds great.

10F/8424 & RS225-8 FAST / WAW Ref Monitor

You won’t find a more expensive driver from ScanSpeak, SB Acoustics, Tang Band, etc that can do what this $60 driver does. Really in its own class.

It's a very flexible driver that can do a lot very good, but some scanspeak or sb acoustics are still a league above on sound quality in the right enclosure (wich is mostly a bit bigger) if you ask me. But when space or budget is an issue, this one is certainly one of the best options, and even when it's not, it's still a very good driver for a not so big sub, that is certainly true. It may be the best shot for your project. A 50L vented cabinet should give you an F3 of +/- 30Hz so. Just don't give it more than 40w if you want it that low (xmax limits the low above that).
 
I can highly recommend the RS225-8. It is unique in that it is wide and and very flat. The breakup doesn’t happen until 7kHz so you can use a first order XO and it sounds great.

10F/8424 & RS225-8 FAST / WAW Ref Monitor

You won’t find a more expensive driver from ScanSpeak, SB Acoustics, Tang Band, etc that can do what this $60 driver does. Really in its own class.
Looks good only not efficient enough for my low watt SET fetish to be of interest as something I'd like to build.

I was thinking MA A10p (or A12p) with the Eton "Orchestra" 12-612, 12" paper cone 93dB 8Ω woofer which isn't too ridiculously priced or if the latter isn't an issue then the Eton 12-212/C8/62 Symphony II 12" 92dB 8Ω hexacone woofer (60Hz f3 in a 1cubic foot sealed box). I'm not experienced enough to say which of the two would work better with a low order passive crossover, perhaps those who do can chime in?