[Bassment]

I am in the preliminary stages of this design. So far here is the plan:

Left and right will be dual 15" woofers, MTM, with a SEOS18 and BA750

Center will be a single 15" with a SEOS18 and BA750, built into the middle of a TV stand. Well, more like my tv stand + component shelves will be built into my speaker, haha.

I'm going to do a fancy design and finish, piano black lacquer and something that looks interesting, more than just a big box. If anyone has any cool speaker design ideas let me hear 'em, I'm thinking B&W 801D style cabinet (with an extra woofer on top of course). I'm not sure how to do the waveguide without making it look odd.

EQ + crossover will be the new miniDSP 2x4 HD, two of them. I have an inuke nu4-6000 for the woofer amps, and I already have the BA750 and SEOS18. I'm looking for an older receiver with 5.1 ch inputs to use as the compression driver amp. Crossover will be between 650 and 700 hz.

I'm 90% going with Deltalite 2515 woofers, unless there is a better option I find (maybe the upgraded ones if they're done in time). They'll be in ~3 cu ft sealed box each.

I was going to do this in baltic birch but after building two huge subs out of it, I'm not so sure now, because I am finding that flush trimming, roundovering and just routing in general causes a lot of splinters on the face of the wood, which would be a problem for a high gloss finish.

 

[Face2]

I've never had any luck with rounding over Baltic birch, but sacrificial pieces of wood can be used to prevent splintering elsewhere.

 

[Scott Simonian]

I like the sound of this project.

For the enclosure material, how bout build most of it from BB and any part that needs special routing be made of softer MDF?

Very interested how this project comes about. Also interested in what you think of the SEOS18/BA750 combo.

 

[jshadzi]

I've had good results, be sure you have sharp bits, also be sure you're always routering perpendicular to the laminated layers, if you router in line with it the chance of splitting the layers apart is much higher.

Recent project I did

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[FriscoDTM]

Looks like a great project, subscribed!

 

[LTD02]

sounds like a great project...


how is the noise floor on the miniDSP 2x4 HD?

 

[Tip24/96]

Is the BA-750 a 1" compression driver? Or is it a 1.5"? I get it confused with the FL-450. I actually have a Seos-18 in a 1" size. Haven't decided what to do with it. I was initially going to use it for my center channel with either the BA-750 or FL-450 (which ever it fits) along with a JBL-2226 for the lows. I am really wanting to build a JBL-3732 clone, though. I will keep an eye on this thread, might clone yours.

 

[Bassment]

I like the sound of this project.

For the enclosure material, how bout build most of it from BB and any part that needs special routing be made of softer MDF?

Very interested how this project comes about. Also interested in what you think of the SEOS18/BA750 combo.

Not sure that would work out, I think having different wood that expands differently with moisture might be worse than just going full MDF. I'm going to do the "trench method" with a crown molding bit on all the seams and fill them all with bondo.

I've had good results, be sure you have sharp bits, also be sure you're always routering perpendicular to the laminated layers, if you router in line with it the chance of splitting the layers apart is much higher.


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Yeah but how do you round over the corners without going parallel to the laminated layers?

sounds like a great project...


how is the noise floor on the miniDSP 2x4 HD?

Not sure, I don't have it yet and can't find any specs on it online. All the miniDSPs seem to get noise floor complaints, but I think it should be fine with a proper gain structure.

 

[Face2]

Is the BA-750 a 1" compression driver? Or is it a 1.5"? I get it confused with the FL-450. I actually have a Seos-18 in a 1" size. Haven't decided what to do with it. I was initially going to use it for my center channel with either the BA-750 or FL-450 (which ever it fits) along with a JBL-2226 for the lows. I am really wanting to build a JBL-3732 clone, though. I will keep an eye on this thread, might clone yours.

1" exit, 2" voice coil.

 

[Mfusick]

Cool build

 

[NWCgrad]

This should be fun to watch. Sub'd.

 

[LTD02]

sounds good. if it is too noisy an L-pad or autoformer can bring down the sensitivity of the cd.

 

[Bassment]

sounds good. if it is too noisy an L-pad or autoformer can bring down the sensitivity of the cd.

Wouldn't just lowering the output volume on the minidsp get the same result? I think the problem most people have had with the noise floor is that they use the source as the volume control and just have the minidsp outputting at max. But if the minidsp output is reduced then I think the noise floor is also reduced.

 

[jshadzi]

Yeah but how do you round over the corners without going parallel to the laminated layers?

Basically ensure your router base is always sitting flat on a piece of laminate and never the plywood's "end grain". If you have to go through a short section of end grain, slowly router in the clockwise direction, this ensures the router blade is cutting from the "outside in" and prevents the splintering you can see when the bit lifts the layers of plywood in the outward direction.

 

[Bassment]

Basically ensure your router base is always sitting flat on a piece of laminate and never the plywood's "end grain". If you have to go through a short section of end grain, slowly router in the clockwise direction, this ensures the router blade is cutting from the "outside in" and prevents the splintering you can see when the bit lifts the layers of plywood in the outward direction.

My router might just be bad, I have brand new bits so I doubt it's that. What RPM/ bit size do you use? I have been using 17500 rpm with 1/2" spiral upcut for speaker cut-out, 1/2" flush trim, and 3/8" roundover, all 1/2" shank. Maybe I just went too fast, I tend to rush my cuts haha

 

[jshadzi]

My router might just be bad, I have brand new bits so I doubt it's that. What RPM/ bit size do you use? I have been using 17500 rpm with 1/2" spiral upcut for speaker cut-out, 1/2" flush trim, and 3/8" roundover, all 1/2" shank. Maybe I just went too fast, I tend to rush my cuts haha

I use a Bosch 1617 router, when I'm doing edge work or round overs I'm always in the solid base (not the plunge base), I run the speed in the middle, not sure the RPM but likely in the 15-20k rpm range. I used bits from Freud, Magnate, Diablo and Whiteside. For a 3/4" radius round over my favorite is the Diablo available from HD, has 3 cutting bits and is buttery smooth.

Definitely use a measured consistent feed speed and don't rush it, that's something that can really ruin a cut.

 

[LTD02]

Wouldn't just lowering the output volume on the minidsp get the same result? I think the problem most people have had with the noise floor is that they use the source as the volume control and just have the minidsp outputting at max. But if the minidsp output is reduced then I think the noise floor is also reduced.

noise floor is what is left after all attempts to remove any signal whatsoever. it is the noise of the device itself with its inputs shorted (no signal in). noise floor or "self noise" arises from a variety of factors but is unrelated to the volume control. of course the volume control can "amp up" noise further up the signal chain (which is what I think you are referring to), but volume control can only reduce self noise to the device's noise floor.

the only way to reduce the noise floor once the noise is introduced is to tradeoff headroom in order to reduce the whole output and that can only be done passively (at least with current technology). fortunately, with c.d.'s having so much more output than is necessary even in ultimate home systems, taking 12db or more out of the headroom to have a 12db lower noise floor benefits the noise floor without causing any practical reduction in output.

 

[Bassment]

noise floor is what is left after all attempts to remove any signal whatsoever. it is the noise of the device itself with its inputs shorted (no signal in). noise floor or "self noise" arises from a variety of factors but is unrelated to the volume control. of course the volume control can "amp up" noise further up the signal chain (which is what I think you are referring to), but volume control can only reduce self noise to the device's noise floor.

the only way to reduce the noise floor once the noise is introduced is to tradeoff headroom in order to reduce the whole output and that can only be done passively (at least with current technology). fortunately, with c.d.'s having so much more output than is necessary even in ultimate home systems, taking 12db or more out of the headroom to have a 12db lower noise floor benefits the noise floor without causing any practical reduction in output.

Right, I meant noise floor of the system not the miniDSP itself. Hopefully the miniDSP's noise floor is low enough to not be noticeable when set up with a proper gain structure that I won't need to do a headroom reduction like that.

 

[NWCgrad]

... Hopefully the miniDSP's noise floor is low enough to not be noticeable when set up with a proper gain structure.

This is what I really want to know. Would be great if the miniDSP HD models have acceptable noise floor. This would make my upcoming build significantly more affordable.

So far I have not found much to like with cheap DSP solutions in regards to noise floor. For subwoofers not a significant issue, but for CD+waveguide it can be a show stopper.

 

[Mfusick]

You could use a table saw to put and angle on it and take off corner which could look cool.