Suggestions for small (8"/10") subwoofer driver?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Suggestions for small (8"/10") subwoofer driver?

I'm planning to build some modest dipoles to be used in a small room based on Linkwitz's suggested configuration (www.linkwitzlab.com/proto.htm). I'd like to build some fairly small subwoofers to complement these in an attempt to cover the range from approximately 20Hz to 150Hz. These would basically act as speaker stands for the dipole panels (~12.5" x 15") and I'd like them to be fairly compact as well (i.e. short depth). I figure that the space constraints will limit the volume to around 1 to 1.5 cu. ft. max. - using a sealed enclosure.

If any of you can recommend small subwoofer drivers that you've had good experiences with it would be most appreciated! I've looked at (for example) the Peerless 830452 XLS 10" which they claim can get to an F3 of 20Hz in only 1.24 cu. ft. (using their matching passive radiator) - but this is way over the budget I have for what is supposed to be a modest setup used at lower listening levels - and primarily for music, not home theater (although HT use would be nice). In other words, the output level requirements are not very high. So, I'm down to the following rough requirements:

Cost: Around US$40 to US$70 per driver
Can reach fairly low in 1 to 1.5 sq. ft. enclosure (using active EQ with bass extension compensation).
Can be driven with approximately 100 to 120 watts (8 ohms) with some peaks to about 180 watts possible.
Compact - i.e. 8" ideal, 10" okay, 12" probably too much....
:)

Any suggestions?

Dayton Quatro? Peerless HDS? Madisound Sledgehammer? Others? Any and all pointers/suggestions most appreciated!

Thanks!

Bill
 
I've modeled the Eminence Lab12 driver in a 1 cu ft sealed box with a Linkwitz Transform, and gotten pretty good results. You need about 350 watts though to get it all the way down to 20 Hz. If you were to have one of these on each side, I bet the bass would be quite impressive.

Cheers,
Zach
 
Monopole or dipole sub?

If it's dipole, I have seen a dipole with the classic Peerless 12" sub which looked pretty good, but as a monopole this sub needs a fairly large box. The Peerless 10" CSX looks like a good choice. You can get a 12" high excursion driver like the Shiva/Peerless/Dayton to go low in a 1 cu ft sealed box with eq, but with cheaper/smaller drivers your output will be limited. With your aims I'd go with an 8" or 10" in a moderately sized vented box.

Perhaps you might start with the 10" Peerless CSX in a vented box. If it is too large, you might consider the 8" version or perhaps the XLS 8" which is designed to work in a small box.

Considering the depth required behind your dipoles, you should have plenty of depth to work with to make a sub bigger than 1 cu ft. If width is an issue, you might make the sub side firing, but don't cross it too high in that case (pref below 120 Hz)

hope this helps,
Paul
 
The CSX257 might have large nominal linear excursion, but looking at the rather soft membrane and the rather small surround, I think there will be strange flexing phenoma if you were to really use the +/- 9 mm linear travel. Besides, the only venting is holes in the cone to vent the space beneath the dust cap, no pole or spider vent, so it is not among the most quiet.

I had been planning to use Vifa M25WO47 coated paper cone drivers. They only have half the excursion of the Peerless, but at this level, distortion and wind noise is low, however you need 8 of them to make up for the low travel. Nice thing is that the basket is pretty flat, so you can fit two in a W-baffle that is only 25 cm wide.

I have been thinking about using more modern drivers, so I might have eight of those beauties for sale...


Oh, there is a Visaton 8 inch, TIW200XS, glas fibre cone, enormous linear travel, vents in pole piece and gap, vented spider. Is supposed to be absolutely quiet running at 20 Hz at full excursion. But then, I'd not really use an 8" for a dipole.

Eric
 
diyAudio Moderator Emeritus
Joined 2001
According to Linkwitz, dipoles exhibit "suck in" at resonance, just as vented boxes do. To avoid this, you need a symmetric magnetic field. This is accomplished by either a shorting ring, (Faraday ring) or an extended pole piece.

"Suck in" is where the speaker actually moves out of it's cneter position and travels all the way to the end of it's excursion, wher it tries to move back and forth from there. Of course, being already at the end of the line, it really can move in only one direction, and half the waveform it is trying to produce gets sheared off.

Vifa is the sister company of Peerless, which mostly has symmetrical fields on it's products-not all. Also, in it's literature, Vifa mentions it's cast magnesium baskets as cutting down on the magnetic field, and on some woofers, it mentions "optimized for long excursion"-"suck-in" tends to occur at points of high excursion.

So Vifa seems to hint at symmetric magnetic field, but never outright declares it has one.

Danish Sound Technology, the parent company of Vifa, Peerless and Scan Speak, says it does not take Emails from consumers. It refers tech questions to it's distributors.

I have already Emailed Madisound, normally an excellent outfilt. They have not responded.

Come to think of it, I think I'll Email Parts Express on this issue right now.

If anyone knows that Vifa does not exhibit "suck-in"-also called "oil-canning"-please let us know. It would be nice to have an alternative to Peerless on this issue.
 
First off - many thanks to those who have responded! Great info so far. But I'm thinking I should be more specific about my goals - and also admit that I'm "waffling" somewhat, so here goes:

Linkwitz described some fairly small and inexpensive dipoles as a way to experiment and "test the waters". His suggestion comprised using an 8" driver (Vifa P21WO-20-08) along with a tweeter (Vifa D26TG-35-06) mounted on a small (12.5" x 15") baffle. Total depth is just over 3.00" or so. So far, so good. The caution that he gave was that the output levels that could be achieved were limited (not a problem in smaller rooms, however). The other constraint mentioned was that the lower frequency response was limited because trying to equalize the 8" driver to produce lower response would quickly run into the excursion limits and would be pointless. The implication seemed to be that THIS was the limiting factor to achieving greater SPLs.

So, figuring I could live with the lower output levels for my needs (small room, etc.) I wondered about how to extend the design to produce a "full-range" (albeit limited output) speaker. In this case I define "full-range" as extending down to approximately 30Hz minimum, with 20Hz being ideal (not accounting for room gain).

I assumed (maybe incorrectly) that the way to do this would be to graft on a small subwoofer and I also assumed that I would need either a sealed enclosure (to keep it small) or a vented enclosure (to lower the F3). The problem is that we're now back to a monopole configuration - and the point of doing the dipole in the first place was to minimize room effects and gain some of the advantages of a "planar" configuration. To correct this - and return to a dipole configuration - seems to involve using some major-league drivers (in multiples!) and the cost starts to go up exponentially...:)

But, I'm still interested in looking at the dipole configuration for the bass IF I can figure a way to keep the cost down. I'm wondering if using a SINGLE driver would be worth it and have looked at the following as a starting point:

Peerless CSC-X - 850146 - 10"
(Fs=22.6, Qts=.35, Vas=144.4, xmax=+/- 9mm, Power=200W)

Peerless CC - 831727 - 10"
(Fs=22.3, Qts=.34, Vas=136.2, xmax=+/- 9mm, Power=220W)

Of course, there are many others, but these are low cost. I'm wondering if they would be a good match for the other drivers (specified above) or if it would really require two of them (?)..... given that we're trying to cover a range from approximately 20-30Hz to approximately 100Hz while matching (roughly) the power output of the two other drivers.

I can already see that it's going to take ALOT more work, and ALOT more $$$ to get this done.....:rolleyes:

Regards,

Bill
 
Bill,

Here is a link that might interest you:

Dirt Cheap Dipoles

Now for the bass. A cheap and simple option, which you might start with, is to use the CSX in a vented box and use it as a stand on either side for your dipoles. Stepping the budget up, you might go with a sealed sub with the Peerless 12" XLS driver following the Thor design.

The Peerless 12" classic subwoofer driver is a good one for dipole I from what I have seen, and is affordable. Here is an example:

Contrapunt dipole sub

If I were you, I'd use the Stryke drivers that you were looking at for your other speakers and see how they go. Use them with the classic Peerless 12" (2 per side) and add a Linkwitz Thor sub if you want to get a little extra depth (preferebly used below 40 Hz to go with a dipole).

cheers,
Paul
 
Paul,

Thanks for the links! Very interesting read...

I think I may try this sequence of events in order to experiment (well, until I change my mind - which might be an hour from now, three days from now, or basically at any time until I've actually built something :) ):

1. Build a baffle of approximately 12.5" by 40". Stuff the Vifa 8" and Vifa tweeter recommended by Linkwitz into the top. Near the midsection, put in the Peerless CSC-X 10" driver. See what happens (i.e. measure, measure, measure - correct, correct, correct - using active circuitry to tweek the thing - notch filters, various slope, low freq. extension, etc. - this is stuff I can actually do and enjoy - measuring speaker enclosures, etc. is dreary stuff to me because it smells like too much math :) ).........

2. If more low end is required, add another CSC-X driver and adjust the amplification available (still have room on the large baffle mentioned above)...

3. If still unsatisfactory - replace second CSC-X with Peerless XLS and retest and align..........

4. Depending on the outcome of (3) above - consider enclosing the subwoofer section (still easy because of the open baffle) and test various enclosure volumes, sealed vs. ported, etc.

5. If we've gotten this far and still don't have something reasonable - start perusing the adverts for used Quad, Magnapans, etc. - and stock up on beer before the bank account is depleted - i.e..............DONE!!!!.....:) :) :)

I think eventually I'll just get started with the experiments instead of trying to analyze it all to death...:) Should be fun!!!

Regards,

Bill
 
diyAudio Moderator Emeritus
Joined 2001
Well, I sent the Email off to Parts Express about the Vifas. Unfortunately, they do not carry Capslock's M25WO47.

I sent off to ask about the symmetrical magnetic system for the following woofers:

P21WO-20
MG22W009-08
TC18WG49-08

I must admit that it doesn't look good for any of these having a shorting ring or an extnded pole piece, the way a symmetrical magnetic field is achieved. The reason is that as I looked at the Parts Express website, only the XT line mentioned anything like "a low distortion optimized motor system", which sure sounds like a symmetrical magnetic field. However, the XT line starts at around $100 for an 8" woofer-more expensive than the other Vifas.

I'll let you know if Parts Express responds.
 
Bill,

I have two suggestions. Instead of the CSX, use the Peerless 831857 - it is only slightly more expensive and as a 12" driver won't have to work as hard as the 10" CSX. A single CSX works in a smaller vented box than the 12" but for dipole use I'd go the 12. Also I would use 2 in push pull mode as this gives lower distortion. Otherwise I think your output with one CSX in open baffle operation will be marginal, personally I wouldn't even try it. Yes the XLS does have more output but it is also twice the price, for not much more output.

Happy experimenting ;)

cheers,
Paul
 
frugal-phile™
Joined 2001
Paid Member
For a pr of cheap subs have a look at the ApexJr 8" Subwoofer and the OEM VIFA 8" that steve has at ApexJr.

And for really Frugal-phile(tm) set of woofers nothing works as well as a set of 10 or 12" extended range drivers salvaged out of a set of dirt-cheap thrift store specials -- find some older ones where the surrounds aren't foam and you often find something decent (i've a growing collection of Corals & Fosters)

dave
 

Attachments

  • coral-foster-10wside.jpg
    coral-foster-10wside.jpg
    49.4 KB · Views: 575
Planet10, slightly OT

The drivers on the left picture, thats a coral 12L60 or something, i might have a pair lying around in the basement somewhere. Had them 15 years ago in a 125L ported enclosure giving lots of rumble.
Have u tried to do anything with them yet ?

cheers
Andreas
 
Stay away from the Peerless CC-260 woofer, much higher distortion than the CSX257. Only advantage is a porous dustcap that lowers wind noise, but has other side effects.

I believe the current version of the Vifas is M25WO49. There were various versions over the last couple of years with essentially the same parameters. Only difference I could find was dustcap design. I am not saying they are the perfect dipole woofer driver, but if you can get them cheaply, they will do a pretty good job.

Eric
 
frugal-phile™
Joined 2001
Paid Member
Andreas said:
The drivers on the left picture, thats a coral 12L60 or something, i might have a pair lying around in the basement somewhere. Had them 15 years ago in a 125L ported enclosure giving lots of rumble.
Have u tried to do anything with them yet ?

I'd have to go downstairs to check the number, but it is a 10" Coral. Plans were to use it with a pr of very special 3" Tandbands, below about 250 Hz in an active system.

dave
 
Peerless 831727

I have built 2 isobarik subs using the above in iso-barik config in a bass reflex 75 liters box, I ended up with an F3 at about 23 hz and clean output up to 97 db which is pretty good. Awsome with music, drawbacks are they can bottom on HT, Am using Peerless 10 inch XLS with passive in a 1 cu ft box for HT, F3 of abour 32 Hz but a lot more punch.
Cheers
Dan
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.