BD15 as a subwoofer. (BD-Design)
Hi,
I have the Medallion III/DX3 and I want to build a subwoofer.
I was thinking about the BD15 Reference basic for start and maybe the ultra later.
1. Anybody tried using the BD15 as a subwoofer?
2. Does it fast enough to keep up with the lowthers?
3. If I use the reference ultra as a sub, what will I gain by using the BD15 horn?
Bert, can I buy only one woofer?
Thanks,
Yehuda.
BD15 as a subwoofer.
Hi Yehuda
I have done a similar thing to underpin my Hedlunds.
[img]http://server3.uploadit.org/files/ChrisV-HiFisystem.JPG[/img]
The BD15 is an excellent driver. Not only does it go deep into sub territory but equally important is that it is optimised to reach upward to the meet the lower frequencies of the Lowthers.
It integrates excellently and is the first 'sub' that I have found to keep up with the speed of the Lowther (previously REL Storm which is no slouch).
You do not have to build the exact reference cabinets, just keep the internal volume the same and also the relex port dimensions.
One BD 15 will perform great but because it is reaching higher frequencies than most subs the positioning is more important. A pair is better;-) ;-) ;-)
BD15 as a subwoofer.
Thanks,
What is the crossover frequency of your 'sub'?
BD15 as a subwoofer.
Hi Yehuda
I use Bert's recommended configuration. You should find this elsewhere on this site.
I take additional outputs from the main amp and run this into Bert's passive low pass filter (set about 70 Hz). This knocks down the signal 'strength' so the output of the filter is now suitable to be fed into the conventional inputs of another amp which drives the subs.
Cheers Chris
BD15 as a subwoofer.
by GC 
, Ottawa, Wednesday, October 19, 2005, 22:57 (6763 days ago) @ GC
... to be fed inot the conventional inputs of another amp which drives the subs.
What apms do you actually use to drive the subs?
Thanks,
Dmitry
BD15 as a subwoofer.
Hi Dmitry
Have look here at my post below. It was a long search but I ended up with the Sugden A21a
http://www.bd-design.nl/forum/index.php?id=9901
BD15 as a subwoofer.
by GC , Ottawa, Canada, Tuesday, January 09, 2007, 12:13 (6317 days ago) @ GC
Hi Dmitry
Have look here at my post below. It was a long search but I ended up with
the Sugden A21a
http://www.bd-design.nl/forum/index.php?id=9901
Thank you for the link. Sugden A21a is a respectable choice 
.
Why didn't you go with Bert's BD30's? To be able to sale it easier in needed?
My speakers are similar to yours. Same DX-4 in back loaded horn (Passion) powered by SE tube amp (Obsession) (http://ca.geocities.com/dk-diy@rogers.com). I'd want to add BD15 based subs to the system and, assume, would need something similar to Sugden A21a or BD30. Both are costly. Did you consider any tube DIY amps for this?
Regards,
Dmitry
BD15 as a subwoofer.
Hi Dmitry
Why didn't you go with Bert's BD30's? To be able to sale it easier in
needed?
I try to stick to the rule of listening before buying and Berts stuff is not widespread in the UK:-( .
At the time there were no reviews of the BD30's out there from others that had tried it but since then some great reviews have appeared.
The Sugden has a firm following in the secondhand market in the UK and given that I was getting through amps at quite a pace this did influence me. Luckily it fits the bill perfectly.
My speakers are similar to yours. Same DX-4 in back loaded horn (Passion)
powered by SE tube amp (Obsession)
(http://ca.geocities.com/dk-diy@rogers.com).
I dont know the Obsession. You have made a fantastic job of construction. Remember with this orientation the bass is only as good as that from your main amp.
I'd want to add
BD15 based subs to the system and, assume, would need something similar to
Sugden A21a or BD30. Both are costly. Did you consider any tube DIY amps
for this?
There are thousands of amps available and its impossible to try them all. One key point is to try for a sub that has a valve-like sonic signature for best integration. I have little or no skills at electronics so shy away from DIY, but if you are OK at that sort of stuff then chip amps may be a possibility. It may be a sweeping statement but good bass seems to be difficult to achieve from cheap valve amps, though others may know better;-)
Incidentaly I would agree with Bert that stereo 'subs' are the way to go. You are asking them to contribute to some pretty high frequencies, way above the notional crossover values and they hence become more 'detectable'
Good luck, Chris
BD15 as a subwoofer.
by GC , Ottawa, Thursday, October 20, 2005, 15:51 (6763 days ago) @ GC
Thanks Chris,
Appreciate your time answering this. I'll try to think more about using tube amp for the bass but in general you're right - good bass is difficult to achieve from the cheap tube solution.
I dont know the Obsession.
Passion and Obsession are my own names. I designed the amp for the horns. It gives really good bass (flat 20...20'000 Hz), - it's horn's natural inability to reproduce it respectively.
Regards,
Dmitry
BD15 as a subwoofer.
Hi Yehuda,
1. Anybody tried using the BD15 as a subwoofer?
2. Does it fast enough to keep up with the lowthers?
Chris already answered these questions...
3. If I use the reference ultra as a sub, what will I gain by using the BD15 horn?
No, in the range below 80Hz the horn has no influence to the bass. The horn is used for optimal integration with the mid-high horn (usually in combination with the Oris 200).
Bert, can I buy only one woofer?
Yes, no problem. But why only one? Even in the bass below 60Hz there is still stereo information present and besides that, the only way to use one subwoofer is to mix both channels which will have impact to frequencies for at least one octave above the crossover frequency.
Ciao,
Bert