DIY sub for Neumann KH420

[dachermann]

Dear all

I am running a pair of KH420 in a heavily treated room of 23sqm. They are linearised by a Minidsp shd preamp. Now, I am eyeing with improving the bass response with 2 subs. As I do not habe enough space for the kh870 pr kh810, and the kh750 is not loud enough, I am looking into two subs. Max. volume is about 50l and the chassis diameter must be below 330mm. The subs shall be powered by a pa amp (will be purchased later). There are no restrictions in terms of costs.
Any ideas?

Thanks David

 

[alex-z]

https://www.parts-express.com/Dayton-Audio-RSS265HF-4-10-Reference-Series-HF-Subwoofer-4-Ohm-295-460

Those drivers in 50 litres have a QTC of .678, -3dB at 40Hz, -10dB at 23Hz.

Power handling per sub is roughly 100 watts, assuming you respect the xmax and don't use a high-pass filter. If you do use a high-pass filter (2nd order @ 20Hz), that will move the -10dB point to 25Hz, and power handling would rise to 190 watts. Most PA amps include such a filter, some don't even let you disable it.

With 190 watts, each sub can produce 95.4dB at 23Hz at 1 metre in half-space, meaning no room gain. With subs + room gain, you can expect 110dB comfortably.

 

[jhaider]

What's available to you locally?

When I see, 12" woofer, 50L cabinet, my first thought is "ScanSpeak Discovery 12." But if that's not an option there are plenty of other good drivers out there.

 

[hege]

With 190 watts, each sub can produce 95.4dB at 23Hz at 1 metre in half-space, meaning no room gain. With subs + room gain, you can expect 110dB comfortably.

There's no budget, so why would anyone want to go with a small 10"? Driver near it's Xmax is not playing "comfortably".

Something like CSS SDX12 in a small cube would get 10dB more per sub at 20hz. (and 4-7dB more compared to any Dayton 12" or similar)

Creative Sound Solutions SDX12 12" Sealed Subwoofer DIY Kit Review

We built and tested the Creative Sound Solutions SDX12 Subwoofer kit. Does the DIY 12" sealed subwoofer kit buy you more performance than commercial offerings? Read on to find out.

www.audioholics.com

 

[Rednaxela]

No non-DIY options that meet your requirements?

 

[dachermann]

Thanks for the input - I would like to stay within 4kEUR for the 2 subs and the pa amp. However, it’s not a strictly limited budget

Due to the limited size of the enclosure I couldn’t find a suitable non-diy sub - but would be open to that.

As the Neumanns already have a very good and tight bass response, I am looking for a suitable, small subwoofer. Does the css or dayton sub acoustically fir to the Neumanns?

 

[Wolf]

You said "not loud enough", so, how loud is enough? How low do you want to go?

 

[Wolf]

There's no budget, so why would anyone want to go with a small 10"? Driver near it's Xmax is not playing "comfortably".

Something like CSS SDX12 in a small cube would get 10dB more per sub at 20hz. (and 4-7dB more compared to any Dayton 12" or similar)

Creative Sound Solutions SDX12 12" Sealed Subwoofer DIY Kit Review

We built and tested the Creative Sound Solutions SDX12 Subwoofer kit. Does the DIY 12" sealed subwoofer kit buy you more performance than commercial offerings? Read on to find out.

www.audioholics.com

I hate to say it, but the actual Adire stuff compares favorably if not better than the CSS SDX12, and you still get XBL.

 

[dachermann]

I am looking to something north of 110dB at 30-40Hz with both subwoofers to habe enough headroom.
Scanspeak is great but needs too much volume.
I restrict myself to 12“ as I would like to place the subs underneath the Neumann‘s. However, might be too restrictive….

 

[morpheusX]

I would do a DIY clone of PSA S1512M, which uses the mighty B&C 15DS115 driver.

Reviews for the 21" brother:
- https://audioxpress.com/article/test-bench-b-c-speakers-21ds115-21-inch-woofer
- https://data-bass.com/#/systems/5d02b177d6b2560004ebe49e?_k=8zwgxi

 

[gy-k]

A net volume of 48l is just about right for 2x BMS 12S330. Fb, Qtc around 60Hz, 0.5. I'd guess the drivers would consume 9-10l volume, so that would make it 58-60l box.
Check out the box volume calculator in Vituix. Maybe 12mm wall thickness is already adequate, with double thickness on the front and rear. That would look like a 350x350 x 600 tall box. An 500W amp could drive the woofers past Xmax.

 

[Ciobi69]

2 15 inch monoprice monolith

 

[FeddyLost]

Thanks for the input - I would like to stay within 4kEUR for the 2 subs and the pa amp. However, it’s not a strictly limited budget

As a user, I'd recommend you to look at ML Dynamo sealed ones. 1600X is slightly over your budget, but they are almost as compact as possible and have good measurements according to review.

I restrict myself to 12“ as I would like to place the subs underneath the Neumann‘s. However, might be too restrictive

I'd recommend you to model such placement in REW Room simulation at least.
Usually It's not very optimal in sub range.
If you need 2 subs either for DBA or 2.2, you'll most probably have to place them according to modal distribution in room, not as a stands for mains. Otherwise they will have same modal problems as mains have but maybe without "floor bounce notch".