First diy sub - need to go DEEP not LOUD

[sharpi31]

I've decided to build a subwoofer to add extra bass depth to my main loudspeakers. Currently I have Rogers LS5/9 which are 3dB down at about 50Hz. I'm looking to fill the 20Hz to 50Hz gap.

If possible, I'd like the sub to be clean up to 150Hz so that I can use it with a wide range of main speakers.

The priority is clean depth - volume comes second.

I'm tempted to purchase the Reckhorn A-402 as it seems to offer more tweaking than most plate amps.

I don't mind a big box, so I was thinking along the lines of a 15" driver in a sealed cabinet....

What would you guys recommend?

[mikee55]

Read this
http://sound.westhost.com/project71.htm

[simon5]

It will depends on your budget.

If your budget is high, I would build a big cabinet using an Acoustic Elegance AV15-X with dual PR18 passive radiators. You can tune that really low, 15 Hz or so.

Since the inductance of the AV15-X is really low, you could cross at 150 Hz without any problems, especially if you center it between your mains, or if you build dual subwoofers.

Good luck !

[valleyman]

If you want a 15" that will go low sealed have a look at this:

http://www.bmm-electronics.com/docum...\RSS390HF4.pdf

That shop is based in the the netherlands too so shipping is cheap and easy to the UK

[Dr.EM]

Yes, that plus:

http://www.linkwitzlab.com/filters.htm#9

should do nicely. Theres a spreadsheet to work out circuit values after you run a sim on Win ISD.

Download the spreadsheet from here:

http://www.trueaudio.com

linkxfrm.xls

[sharpi31]

I've played around with the Dayton 15" and also the Peerless 830500 XLS 12".

Here are WinISD plots for the Dayton in a 155L sealed box and the Peerless in a 79L vented box with EBS -6dB alignment.

I know I started off looking at 15" drivers in sealed boxes, but the ported Peerless sub is far flatter from 20-50Hz.

Would the Dayton plus Linkwitz transform be better than the Peerless?

[valleyman]

You're discounting room gain. In most listeniing rooms, room gain can start to be considered around 30Hz increasing to around 10dB at 20Hz, but of course it does depend on the room. For this reason I hope you can see you might well achieve a flatter in room response from the sealed 15".
Also bear in mind that EBS alignments tend to suffer from high group delay which is usually fine for HT but can be a problem if the system is to be used for critical music listening

Alternatively, using the Linkwitz transform circuit linked before will yeald a flatter response for the sealed 15" if thats really what you want

[simon5]

Linkwitz Transform also introduce group delay, on the other hand.

If you can afford Peerless drivers, as I said earlier you might want to look at this : http://www.aespeakers.com/phpbb2/vie...php?f=3&t=1715

I think both of your choices would do well but personally I prefer EBS with the Peerless. Just tune the EBS really low and since your box is small, use passive radiators because you can't fit ports long and big enough in that box in my opinion.

Just play with the default EBS enclosure, increase and decrease port size and box size, until you achieve a more gradual rolloff. I don't like the shelf, the small flat part in frequency response, that's usually in the EBS -6 dB default enclosure.

[valleyman]

I just built an EBS sub. It's great and cant be beat for powerful, low bass from a small box, but it is sluggish and doesnt keep up for critical music listening

[GM]

Hmm, I've found EBS to be one of the few alignments that's 'fast' enough to keep pace with compression horns, but they need to be tuned to < 20 Hz to do it.

GM