Sub design with Scanspeak 26W/4558T00

[Billyo]

Hi guys, first post here, so a bit about me first!

I built a HTPC a couple of years ago and have been hooked on DIY AV stuff ever since, since its been a massive success with the WAF sky high. Documented my journey from AV noob to someone who knows a bit more than average on a blog buildingahtpc.blogspot.com.

Massively increased my committment to DIY AV by taking on a Tony Gee LBS floorstander design over 6 months back and finally completed them (well almost) in partnership with a HifimeDIY TK2050 amp. Turned out to take longer and cost a lot more than expected, but the result is amazing.


Since I've now thoughly hooked myself on the hobby of DIY Hifi, I wonder whether anyone can help me... I've posted over at DIYAudio, but my thread hasnt got any traction for some reason.

I'm planning out a subwoofer build to match with the pair of Tony Gee LBS floorstanders – since I bought all the tools and stuff to build the floorstanders, adding new speakers will be relatively cheap (thats what I say now... ask me when its finished) – and first cab off the rank is a subwoofer!

I would have liked to build the Passive Radiator sub using the now discontinued Peerless XLS PR, but since I can't reliably find them anywhere, I've been experimenting in WinISD Pro with a Scanspeak 26W/4558T00 driver and the matching passive radiator 26W/0-00-00 – apparently 'newly released' and sold by WES in Sydney.

Sorry - can't insert links until my post count goes up, but here are the URLs, replace * with .

www*scan-speak*dk/datasheet/pdf/26w-4558t00*pdf
www*scan-speak*dk/datasheet/pdf/26w-0-00-00*pdf

Has anyone built a Passive Radiator design with these Scanspeaks? I heard that the max excursion is not great in the Scanspeak, and I understand that Xmax measurement can be a little inconsistent between manufacturers – but the Scanspeak value of 28mm actually exceeds the Peerless 22mm.

I plugged the stats into WinISD and chose a box size of 30L and added 200g to the PR (as per the similar Peerless design) – the graphs come out like below for the Scanspeaks:

As I'm not yet adept at knowing what I should be looking for in these charts – I wonder whether someone whose done it before would be kind enough to comment on whether this design would be a goer, or whether I've overlooked something catastrophic in the graphs or in entering the parameters. It looks good to me, but only because it seems similar to the Peerless results and doesn't seem to blow up in excursion.

Scanspeak 26W driver in WinISD:
//img710.imageshack.us/img710/7025/scanspeakdriver.jpg


System Transfer function:
//img685.imageshack.us/img685/7227/120wn.jpg


Passive radiator transfer function:
//img10.imageshack.us/img10/2104/prtransferfunction.jpg


Passive radiator cone excersion @ 120W:
//img339.imageshack.us/img339/8707/prconeexcursion.jpg


Driver cone excursion @ 120W:
//img405.imageshack.us/img405/8705/driverconeexcursion.jpg


Any comments appreciated!

thxs, b

 

[gregz]

Hey Billyo, I haven't done much with passive radiators so I can't help you directly. Have you bought the Scanspeaks yet? The reason I ask is that you may be able to find the Peerless used.

Years ago, I started two sub boxes utilizing NHT's, but had only bought one of the two drivers I needed and put the project on hold. When I resumed the project, I found out the NHT's were out of production, and nothing on the market was even close to similar. I found someone here in this forum that had a couple of spare NHT drivers sitting in his closet for a rainy day project, and picked them up for a good price.

http://forums.audioholics.com/forums/diy-corner-tips-techniques/7436-starts-now-zolasoid-ii-project-4.html

You might search around for a Peerless and be pleasantly surprised.

 

[Billyo]

Hi gregz,

Thanks for the response!

Although with a bit of perserverance I did find a few Peerless drivers at a great price, the passive radiator is stubbornly impossible to find.

I concluded that the scanspeaks were not really up to scratch compared to the peerless speakers and so settled on Creative Sound Solutions as the only make nowadays that can do a 10" sub and PR combo that are capable of going low in a relatively small box.

I also discovered that for high performance 10" subwoofers, there seems to be no point in building an original design - as the relatively few 10" drivers out there that get down to my low 20 Hz targets in a small box already have an optimal design and so changing it usually decreases performance.

Surprisingly, there is a CSS distributor in Australia, but they won't be getting any in until early 2012 - so I'll need to bide my time until then.

Thats ok - I've got plenty of other stuff that needs doing!