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▀art West-VL. 6th October 2012 07:25 AM

Pivoting TV-stand/HT-sub/stealth corner
Finally coming to a point in the renovation of the house, that I can work on the corner with the gas, electricity and water meters.
This corner will accommodate a closet from floor to ceiling but needs to pivot open to read the meters.
This will be done by hinges on the left side and two wheels under the right side of the sub-woofer, which will function as a TV-stand and all other equipment.

The front face of this bottom part for the sub measures 114cm wide and ▒60cm high.
so, with x height = 3.74 ft x ▒1.97 ft
The net volume will be at least 400l / 14ft│
There is room for three 15" or two 18" woofers, how to choose? Are smaller ones better? etc.
(I also plan on building two smaller subs to put next to the sofa as side stands)
Although I didn't decide on the type of enclosure, I thought a bass-reflex would be best suited┐
I don't know enough about PPSL but it seems this would lower the frequency in case of a sealed sub┐

The ever lasting discussion about 'how low should it go' is always a problem with HT-subs.
Can I assume 16hz is needed or what do you think about it?

Room size is about 10m x 4.5m x 2.5m or 32.8ft x 14.8ft x 8.2ft

I prefer a bit of efficiency since I haver a couple of old amps that I'd like to use.
One is A-656 Pioneer, dynamic output at 4Ω 2x190W, damping factor 70
The other is from Velleman RMS 2x155W @4Ω, damping >600
Are these or one of them fit for a HT-sub?
If there is no choice, I consider buying an amp.
What about filters? My receiver is a Cambridge Audio azur 540r.
This is not intended to be a reference sub, but how loud should it beat to give good HT experience?

Another thing I like is what I read some time ago on this forum about closing the BR-opening to go sealed in an instant for music.

Please consider I'm from Europe and have not the same options on the driver(s) as in the US, unless the shipping is reasonable.
I also can get 40mm multiplex ( a bit over 1.5") but that might be overkill and reduce the net volume unnecessary...

Anyway, I finally can design for real now, instead of running in circles, but I've learned a lot thanks to DIY Audio and the members!

▀art West-VL. 6th October 2012 10:47 AM

1 Attachment(s)
crude drawing of intended sub:

▀art West-VL. 9th October 2012 05:25 AM

I'm down to driver choice, in the price range of 500€ or so, for multiple or one driver.
Any recommendations?


▀art West-VL. 11th October 2012 06:57 PM

A very respectable forum member has put precious time in E-mailing me with some thoughts and explanations.
Because of this, I'm leaning towards the Monacor SPH450-C

I'm getting really excited about this, feeling like a kid. :)

▀art West-VL. 13th October 2012 06:20 AM

1 Attachment(s)
This is a crude fast drawing of the room it will be in.
Room size is about 10m x 4.5m x 2.5m or 32.8ft x 14.8ft x 8.2ft
Partial wall in the room dividing the kitchen and living room. the ceiling of the kitchen is sloping a bit.
Next to the sub, there's the chimney and a very big masonry stove (proud to say: also diy:))

epa 13th October 2012 07:19 AM

hi bart.
the monacor is a good price/preform woofer.
wall thicknes is good,but good bracing is better(doing both is best)
i like to see the pics when finnished:)

▀art West-VL. 13th October 2012 09:09 AM

Thanks epa,
I'll make sure it's well braced. It seems that I'll have volume to spare, if I go with the Monacor.
The driver choice is the most difficult decision for me, I want to get it right and good the first time.
If anyone has comment for drivers, please reply.

I will be happy to take pics while progressing, I ow at least that to this forum!
It's a difficult build because of the shape the box requires, the right side will not be parallel to the left one because of the rotation on the hinges.
This will take some time to build.

I assume room gain would start at about 17hz and down, is this correct?

tvrgeek 13th October 2012 10:48 AM

Only one way to know anything for sure. Prototype. Build a simple box and set it in place to see what happens. See how it reacts with the room and how it interfaces with your mains. See if you are going to need bass traps to tame any serious problems, or eq those that can't be tamed. I never invest in a complicated cabinet construction until I know what the results will be.

I bet the old Pioneer will do just fine. ( DF is irrelevant I hope you know). I have used many old power amps from a DH220 to my current HCA1200. I also run my subs with a LR4 external crossover. I have several. Everything from a cheap Bheringer, which is more than good enough for a LP, but maybe not as clean as you want for the HP, a DCX and several DIY units. DIY is the only way I know top get the quality you may want considering you have a Cambridge amp. The steeper the crossover the easier it will be to manage nulls with the mains. One of my next projects is to move to LR6 in a room where the sub can't be equal distance from the mains.

mattlong8 13th October 2012 03:28 PM

Hey Bart,
I believe you will see the most significant room gain start around 35Hz and peak around 22Hz. The room dimensions will give you problems around 20Hz and 40Hz. I think that a reasonable compromise would be to target a Vb of 22Hz. That should give you a nice flattening effect with the room gain and you'll probably want to add a bit of EQ too.
As far as the woofer amp combo, I think, if you decide to go with the Monocor, you will should buy an amp.

Your best bet is probably a 4x250W@4ohms for the best sound quality because of the dual voicecoil, but this Behringer: EUROPOWER EPQ304 would probably be enough. A step up might be 4x100W @ 4 Ohm TK2050 Class-T Digital Audio Amplifier Board 320-302. But I think best solution for the money is 2 TAS5630 modules similar to 2x300W TAS5630 Class-D Amplifier Board 320-309. I'm don't know how to look for good European suppliers so you are on your own there.

Best of luck,

▀art West-VL. 13th October 2012 05:50 PM

I would like to know what to look for in the amp's specifications. I was convinced that damping factor was important. It seems I can't be sure of anything any-more, contradicting quotes everywhere. :confused:

I'm not fixed on the Monacor, just leaning towards it for the moment thanks to a forum member.

This is for HT.


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