My 2x DIY Scan-Speak Revelator 32W subs build

[concorde1]

Hi - I have just completed my 2x Scan-Speak Revelator subs, with completely custom 25mm HDF boxes.

Sealed and Passive.

They are powered by a Topping PA7 Plus power amp. Hopefully it will have enough juice.

As you can sort of see, they are coated in a pearlescent and metallic blue. Straight onto the (undercoated) HDF.

Final photo is each sub individually (the other turned off while it's being measured, of course), measured in REW at 5cm up to 500 Hz. (As per MiniDSP Linkwitz page recommendation.)

The best thing is, they worked first time, just like my DIY power amp did.

Also my amp build is in signature if you've not seen.

Questions welcome.

Also I'm unsure how to do a Linkwitz Transform without MiniDSP unit (I am using Topping DM7 multichannel DAC and Equalizer APO).
So if you can assist with integration please do!
I think Delay will be easy to correct, and I've already corrected my main speakers with Equalizer APO. I think I'll crossover the mains/subs at 70Hz.

I have to buy cables now to be able to use speakers and subs at same time so don't have a full spectrum measurement yet.

 

[ppataki]

Also I'm unsure how to do a Linkwitz Transform without MiniDSP unit

Just use Jriver, its Parametric EQ feature does have a Linkwitz Transform filter

I personally don't use it since I think it is an overkill, I simply use a low-shelf filter, or even just a simple peaking filter to compensate for the bass roll-off

 

[concorde1]

Just use Jriver, its Parametric EQ feature does have a Linkwitz Transform filter

I personally don't use it since I think it is an overkill, I simply use a low-shelf filter, or even just a simple peaking filter to compensate for the bass roll-off

Thanks but I really require systemwide EQ (W10 and Linux).

Maybe I'll opt for your alternative solution.

 

[ppataki]

Thanks but I really require systemwide EQ (W10 and Linux).

Jriver can be set to systemwide under Windows, just use its WDM driver

 

[sigbergaudio]

Thanks but I really require systemwide EQ (W10 and Linux).

Maybe I'll opt for your alternative solution.

What would you like to achieve with the Linkwitz-Transform? May seem like an obvious question, just want to make sure before offering advice.

 

[concorde1]

What would you like to achieve with the Linkwitz-Transform?

Well I really just want to lower Fs so that I get (ideally) -3dB at 20 Hz in room.

Maybe I should instead just measure at listening position and EQ bass from there like I do with my speakers?

Below is what my EQ profile looks like ("sointuva trained" is in itself my speaker EQ including its own 70Hz High Pass Filter).

 

[Sokel]

You better use 50dB scale at your charts so we all align at our charts, is short of an unwritten law here.

Really nice built, I love revelators, done right can can be top of the line, nice woodwork and painting too!

 

[sigbergaudio]

@concorde1 I would have a look at what I'm getting in-room in the listening room now before doing too much. Your nearfield measurement seems to have -6dB at 29hz and -10dB at 20hz already which is not too bad.

 

[JohnnyNG]

Very nice work!

The best thing is, they worked first time...

That's my goal for all my DIY projects. Everything else is a bonus.

 

[JohnnyNG]

@concorde1 I would have a look at what I'm getting in-room in the listening room now before doing too much. Your nearfield measurement seems to have -6dB at 29hz and -10dB at 20hz already which is not too bad.

And adding boost that low will eat into the already limited available wattage quite a bit.

 

[concorde1]

Thanks for kind words

I'll post in room response once I have my required interconnects, at 50dB scale.

And adding boost that low will eat into the already limited available wattage quite a bit.

True - maybe I'll sell PA7 Plus for something else

 

[Palmspar]

My last Diy subwoofer project has also the 32W driver in a 40 liter sealed box for qtc 0.707
Use the Hypex FA501 amp, with the dsp the sub is tuned at 22hz-6db and 15hz-10db
In 40 liter the sub plays almost flat, only a single dsp point needed in hypex filter design to extend deeper.

 

[concorde1]

I have opportunity to get a stereo Icepower 700 AS2 amp for a good price.

My only concern is I'd need a second preamp to go between DM7 and Icepower.

Unless I got a second Topping A90, I'd have a preamp with different gain structure.

The only way I could circumvent this is, turn my A90 and [second preamp] to maximum sane levels and use my DM7 volume control to attenuate.

Anyway, is the Icepower advisable for these subs, and what preamp would I get? (The original "A90" is no longer available new.)

 

[ppataki]

Why don't you use software volume control at the source? (PC I assume)
That way you could easily control the volume per channel too

 

[concorde1]

Why don't you use software volume control at the source? (PC I assume)
That way you could easily control the volume per channel too

I thought that would cause loss in quality?

And more importantly, suppose I accidentally maxed out to 100% with the Icepower or my Neurochrome - speakers explode! I think this would be quite possible to do.

 

[ppataki]

I thought that would cause loss in quality?

And more importantly, suppose I accidentally maxed out to 100% with the Icepower or my Neurochrome - speakers explode! I think this would be quite possible to do.

Quality wise, there is nothing better than 64-bit resolution software volume control
Jriver's Internal Volume control is like that for example

It also has a fool-proof volume protection feature to avoid accindental volume changes

 

[concorde1]

I just don't like the idea of plugging my DAC directly into a 700Wpc Icepower.

Also I don't wish to use Jriver personally.

Maybe I'll get a cheaper-than-A90 Topping preamp with XLR outs, and do my:

turn my A90 and [second preamp] to maximum sane levels and use my DM7 volume control to attenuate.

strategy

 

[Flaesh]

I would have a look at what I'm getting in-room in the listening room now before doing too much

Yeah.

Spoiler

Many people talk a lot about the anechoic frequency response of home subwoofers.

 

[concorde1]

Decided to switch round my fancy Neurochrome amp (360W into 4 Ohm) to power the subs, and the PA7 Plus for my speakers. So I don't have to buy anything. Just waiting for the interconnects and will do some full spectrum measurements then.

It saddens me to use my fancy amp for subs, but at least it's going to be under more intense use now

 

[Flaesh]

Just waiting for the interconnects

Ha! I just found a couple of interconnects between the chair and the wall; I hope I'll have time to hook up the subwoofers in the next few days. A pair of V3mono will act as amplifiers.
32W/4878T00 in 77 l, 38 V: