Suggested SubWoofer Driver or Kits

Mark_Walsh · « **on:** 8 Mar 2004, 06:35 am »

Good Afternoon All,

Lots of letters at once, because of lots of thoughts at once.

1. I have just finished and tested my 300W/200W (into 4/8 Ohm) Playmaster Subwoofer kit amp with variable active crossover, but I have no subwoofer speaker as yet. Are there any suggestions on:

a) suggestions for good quality but not ridiculously expensive drivers (say $100 - $250 Australian) around which I can build/or design a box, or
b) ready-to-make kits.

I would prefer to be able to source the products in Australia due to restraints of the length of my bursts of enthusiasm and the onset of gorgeous weather just around the corner, but if there are some "must have classics overseas, I remain all ears - until age deafens me. (My reference on box construction is "Bullock on Boxes".)

(Does anyone bring the Audax speakers into the country any longer?)

I've just gotta get this thing up and going. (Wife Acceptance Factor - moderate. I think she has expected something a bit ugly in the subwoofer for quite a while.) The plan is that this is a quick Easter Holiday project.

Many thanks to all.

Regards,
MW.

PS This post was at risk of being accused of being "off topic", I could not understand or afford many of the other suggestions being made in other "subwoofer" threads elsewhere on this board.

EchiDna · « **Reply #1 on:** 8 Mar 2004, 09:58 am »

perhaps it would be more on topic at the aussie pie or the lab?
anyway, I aint livin in Oz atm, so I can't answer your questions...
with the strong A$, I reckon buying Adire and the like would be a bargain right now...

GL!

JohnR · « **Reply #2 on:** 8 Mar 2004, 10:02 am »

How about the Peerless XLS drivers? The 12" is out of your budget at retail but if you have an ABN it's within. Otherwise the 10" is within, I think.

Mark_Walsh · « **Reply #3 on:** 9 Mar 2004, 04:52 am »

Thanks Echidna,

Posted here because a) didn't know my way round the Bulletin Board too well, b) I can understand most of the jargon in this Circle ... elsewhere's I get quite lost, unable to tell whether people are talking about teeny electronic components or huge systems.

Regards,
MW

AKSA · « **Reply #4 on:** 9 Mar 2004, 05:08 am »

Mark,

The XLS is pretty much a car speaker; not strictly for hifi, with emphasis on small enclosure, strong motor, and very large excursion. I recommend the standard, paper coned 10" Peerless for sub duties in domestic hifi, and about half the cost.

If you want something very small, consider two of these speakers in a single box, since this isobaric configuration halves the size of the box and gives lower distortion at very low frequencies since there is a cancellation.

I have an isobaric using inexpensive 10" paper cone drivers and it is 3dB down at 17Hz. At around 50W power, this speaker threatens the human digestive system......

Cheers,

Hugh

Grumpy_Git · « **Reply #5 on:** 9 Mar 2004, 09:29 am »

Hugh,

Model numbers for the drivers and a few pointers please, just a plain old box?

Until we hear more about possible AKSUB I need a mucho cheapo sub to run off the spare frontchannels of my arcam AV50 which i use as pre amp and surround power amp, I have therefore two spare power amps with my front channels.

These would be great for a cheap effective "Extension" box.

Nick.

AKSA · « **Reply #6 on:** 9 Mar 2004, 09:45 am »

Nick,

I'm repeating much of what Ron, my speaker man, has told me, so my rantings are not of much use, just indicative.

This is the better driver, the 831727 sub-bass, of 10" diameter:

Thiele Small parameters: Free air Common Baffled
Nominal impedance Zn (ohm) 8
Minimum impedance/at freq. Zmin (ohm/Hz) 6.2/123
Maximum impedance Zo (ohm) 41.9
DC resistance Re (ohm) 5.4
Voice coil inductance Le (mH) 3.3
Capacitor in series with 8 ohm
(for impedance compensation) Cc (µF) 25
Resonance Frequency fs (Hz) 22.3 21.5
Mechanical Q factor Qms 2.62 2.73
Electrical Q factor Qes 0.38 0.40
Total Q factor Qts 0.34 0.35
F (Ratio fs/Qts) F (Hz) 62
Mechanical resistance Rms (Kg/s) 2.71
Moving mass Mms (g) 50.8 54.8
Suspension compliance Cms (mm/N) 1.00
Effective cone diameter D (cm) 19.9
Effective piston area Sd (cm²) 310.0
Equivalent volume VAS (ltrs) 136.2
Force factor Bl (N/A) 10.0
Reference voltage sensitivity
Re 2.83V 1m at 123 Hz (Measured) (dB) 87.8

Magnet and voice coil parameters:
Voice coil diameter d (mm) 39
Voice coil length h (mm) 26.0
Voice coil layers n 4
Flux density in gap B (T) 0.85
Total useful flux (mWb) 1.34
Height of the gap hg (mm) 8
Diameter of magnet dm (mm) 115
Height of magnet hm (mm) 22
Weight of magnet (kg) 0.87

Power handling:
Long term Max System Power (IEC) (W) 220
Max linear SPL (rms) / by power (dB/W) 110/315

Note the BIL on this driver; close on 10. That's big. Note also the weight of the magnet, and the long term power handling, with four layer voice coil. This is an impressive speaker. The 830514, with 10.5" diameter and XLS designation, is 4R, not 8R, and has twice the moving mass (117g versus 54 for the 831727 and a BIL of just 11, only 10% more. I admit the 727 is 5dB/watt/metre less sensitive, but for a separate amplifier, this is never a problem. Makes it less peaky, anyway.

Cheers,

Hugh

Blink · « **Reply #7 on:** 23 Mar 2004, 02:39 am »

Now I know you wouldn't let us know about your killer sub without putting some more detailed box specs up on the forum!

Al Garay · « **Reply #8 on:** 23 Mar 2004, 03:21 am »

What is the configuration of your isobaric? Push-pull with both drivers facing each other? What are you using for the amp and crossover?

Thanks,

Al

AKSA · « **Reply #9 on:** 23 Mar 2004, 05:13 am »

Hi Mike81,

Nice one! Nah, it's not that I'm hiding state secrets, its just that Ben and I are working on a sub right now, and the design is nothing like this, I can promise......

Al, the isobaric, as far as I recall, has the drivers facing each other.

However, and here's the rub, I don't bother using it because I find the bass from my AKSonics is more than enough to keep me happy. Even the kids never complain with their appalling rock music.......

Cheers,

Hugh

EchiDna · « **Reply #10 on:** 23 Mar 2004, 08:30 am »

Quote from: AKSA

Even the kids never complain with their appalling rock music.......

Cheers,

Hugh

Ouch! showing your age Hugh

j/k!

Grumpy_Git · « **Reply #11 on:** 23 Mar 2004, 12:50 pm »

I'm sure Hugh made a small typo and meant to say POP music, thats what most so called rock is these days. I do like Jet though, the best thiong to come out of OZ since AKSA.....

AKSA · « **Reply #12 on:** 24 Mar 2004, 01:10 am »

Yeah Nick,

You are right, of course.

Some of it

I actually like however, like Portishead and Goldplay. Ain't all bad......

But the recording quality is something else, so much is poorly produced.

Cheers,

Hugh

PJ · « **Reply #13 on:** 24 Mar 2004, 07:19 am »

Just wait till they discover electronic music..and no, not the crap on the radio

Then you will both see the light

Grumpy_Git · « **Reply #14 on:** 24 Mar 2004, 10:14 am »

Portishead, I havent listened to then in a while, maybe its time to start delving into my collection again for the bristol Triphop stuff. I've been sticking with old stuff recently.

What I really want is my Plastic scratcher back so I can listen to Jimi Hendrix again

. That and My old KLF and Kraftwerk.

I'm only 24 and I love Electronic Music. Dub is pretty good too for the bass monsters, where else will someone record speaker breakdown to make the music sound soooo good.

Mark_Walsh · « **Reply #15 on:** 31 Mar 2004, 10:50 am »

Evening All.

Just to fill up the Bulletin Board a bit and to keep you posted on my 4 year subwoofer project: I have decided to go with 2 * Jaycar CW-2145 12" woofers. (www.jaycar.com.au) Other contenders were the Peerless 831727's a la Hugh, but currently unavailable in Australia, the Peerless XLS 830500 but was AUS$299 before postage (and perhaps GST), and the Audio Adire Shiva 4 (the latter appeared to be a good deal ... including postage and GST currently AUS$272 or so. The foam surround is a bit of a worry though. My JBL foam surrounds have a lifespan of 7-8 years in the subtropics and tropics.) The Jaycar's, through a friend with a business account, come to $132 each. It is handy having friends.

Setting them up as Isobariks clamshells in an approx 120 litre box should give me: low distortion with low cone movement, nice and flat from 40 to 20 Hz with a slight rise (<1.5dB) to about 55Hz. Because of the lower cone movement than with the Shiva, a gentler subsonic filter is usable which helps keep the "group delay" much less than the Shiva.

Hopefully, more punch, etc. Fascinating though how putting in ANY filters jiggers up the phase relationships. Frightening actually.

Thankfully, any bizarre behaviour of the final product can always be excused ... problems with the room, needs more/less damping material, etc. A lot like fishing really, with there always being an excuse.

I must say too, that I am EXCEEDINGLY impressed with the WinISD Pro freeware/shareware product Version 0.50a7.

ReleasedBy=Janne Ahonen
DownloadFrom=http://www.linearteam.dk/statistics.asp?prog=winisdpro
WebURL=http://www.linearteam.org OR perhaps .dk ... one or the other did not work.

So impressed that I am going to get myself a low limit no annual fee Mastercard and send them a little donation.

Regards to you,
Mark.