ART Cleanbox mod thread

**soho54** · **07-02-07, 12:20 PM**

Quote:

Maybe you can be the first one to actually test this modification with REW to prove its effectiveness, and post the REW graph of before and after........ no one else seems willing....

The mod has been tested. It is effective.

Ilkka posted a measuered -10.3 dB loss at 10Hz. Two independent tests confirmed a gain of ~10dB. Looks like it is proven to me.

**soho54** · **07-02-07, 12:28 PM**

Efalegalo, the first is a step down quality wise on it's own. The second is really big, but there should be room. The third is close to what I used, and are two per pack.

Options 1 & 2 will put you in the 1Hz xover range, and opt 3 in the 3Hz range.

Good luck.

**brucek** · **07-02-07, 01:31 PM**

Quote:

The mod has been tested.

I was looking for a test with REW from input to output of the device, much like Ilkka did. It makes it easier to interpret the results.

brucek

**Efalegalo** · **07-03-07, 12:49 AM**

I replaced my caps with the once Thylantry mentioned above. The following results were obtained using the SPL measured at the Sub and using Soho Audio Test DVD.

Hz Before After Variance
16 76.8----------84.8----------8
17 79.5----------85.5----------6
18 80.7----------85.7----------5
19 82------------87-------------5
20 82.5----------87.5----------5
25 88.8----------91.8----------3
30 89.47--------92.47---------3
35 90.1----------92.1----------2
40 92.18--------93.18----------1
45 92.745-------94.745--------2
50 94.3----------95.3-----------1
55 92.3----------93.3-----------1
60 92.5----------94------------1.5
65 92.2----------93.2-----------1
70 91.9----------91.9-----------0
75 91.18-------- 91.18----------0
80 90.876-------91.376--------0.5

My tuning frequency was 15Hz, the mod definitely made a difference. However, I still don't know why I down 6db by 17Hz? Almost 7db at my turning frequency? The above readings have been adjusted for SPL correction found here at Hometheater Shack.

I'm curious whats wrong - Did I not build my subs right?

**ccdoggy** · **07-03-07, 01:18 AM**

remember that another component could be causing a drop in freq response. like an amp that is not as efficient that low but will put out a bit more a little higher in freq. could be a few things.

could also be the natural roll off of the driver you used. im pretty sure its not going to be super flat through out the freqs and it will start rolling off at some point just because thats what happens when you go that low. the Port is (i think) basically just helping extend the response and help out that low down. That statement was purly a shot in the dark with what i know, take it as such.

i used those large blue caps in mine. a pain to get mounted but work great, also need to be squished a bit in there to fit.

**Efalegalo** · **07-03-07, 09:30 AM**

Just for reference: My set-up was:

Panasonic - XR-55 - sub out to Art Clean Box to QSC PLX3402 ProAmp to Dual Sono Sub - TC-2000 SVC 15" (320 Liters tuned to 15hz).

**soho54** · **07-03-07, 09:51 AM**

How close to the sub were you measuring? It looks like it was close, and you didn't get a good reading from the port. The port gives you a lot of the under 20Hz SPL. That is why it is hard to measure a large ported system accurately.

**Efalegalo** · **07-03-07, 10:29 AM**

I held the SPL meter right in front of the woofer, right at edge of the base plate facing it towards the center of the woofer (in other words, really far from the port - on the opposite end, at the driver).

What would be the best way to measure the sonotube design?

Thanks

And thanks you very very much for the Mod tips - it helped immensily.

**soho54** · **07-03-07, 11:43 AM**

We're getting OT now. Going to PM mode.

**ccdoggy** · **07-04-07, 12:53 AM**

here are some pics of my mod.

www.ccdoggy.net/speaker/IMG_2118.jpg
www.ccdoggy.net/speaker/IMG_2119.jpg
www.ccdoggy.net/speaker/IMG_2120.jpg

and i must say it makes an impressive difference. i watched mater and commander again and it really makes quite a bit more impact. definetly worth it.

**ccdoggy** · **07-11-07, 09:48 PM**

anyone end up measuring the mod?

also im wondering what kinda distortion the box brings with it... if you can find that out during the measurement.

**Ilkka** · **07-12-07, 03:05 PM**

Quote:

ccdoggy wrote:

anyone end up measuring the mod?

also im wondering what kinda distortion the box brings with it... if you can find that out during the measurement.

I've already cut her open, now I just need to buy some caps...

I will also take some distortion measurements.

**Ilkka** · **07-14-07, 12:06 PM**

"Let there be bass: and there was bass."

Yes, the mod works. I doubt I have to tell which curve is before and which is after the mod.

I used 1uF 63V polyester capacitors (two red ones in the pic). 63V because they are much smaller than say 250V, and one doesn't need 250V caps when the operating voltage is only ~12V.

**ccdoggy** · **07-14-07, 12:51 PM**

YAY!~!

distortion graph?

is a polyester cap better then the metalized-film i used? or at this point would it make a difference.

**Ilkka** · **07-14-07, 03:06 PM**

Quote:

ccdoggy wrote:

YAY!~!

distortion graph?

Tomorrow.

Quote:

is a polyester cap better then the metalized-film i used? or at this point would it make a difference.

Nah. Metallized plastic film means poly* cap.

http://en.wikipedia.org/wiki/Capacitor#Capacitor_types

**ccdoggy** · **07-14-07, 03:48 PM**

sweet, thanks for the info.

**Exocer** · **07-15-07, 01:22 PM**

This is a great mod and should be available for many people to see. I'd make this a sticky

**Wayne A. Pflughaupt** · **07-15-07, 07:51 PM**

Done.

Regards,
Wayne

**Ilkka** · **07-18-07, 04:58 AM**

Quote:

ccdoggy wrote:

YAY!~!

distortion graph?

Sorry ccdoggy. I didn't have enough time to take any distortion graphs while I was at home. And I won't be there again until after ~1.5 weeks. I will take them then. Although I can already say that any "electronic distortion" is pretty minimal compared to any "subwoofer/speaker distortion". So I wouldn't worry about that.

**Ilkka** · **09-04-07, 05:57 PM**

Quote:

Ilkka wrote:

Sorry ccdoggy. I didn't have enough time to take any distortion graphs while I was at home. And I won't be there again until after ~1.5 weeks. I will take them then. Although I can already say that any "electronic distortion" is pretty minimal compared to any "subwoofer/speaker distortion". So I wouldn't worry about that.

I rarely quote myself, but now it's a good time to do it. I recently performed some distortion measured on the Velodyne SMS-1 and the Behringer FBQ2496. I found some shocking results (you can probably guess which one).

To be continued...here: http://www.hometheatershack.com/foru...html#post50977

**penngray** · **09-11-07, 03:10 PM**

Im about to mod my Cleanbox but I couldnt find any .47 caps at RS.

I did buy 1.0 Tantalum caps (35WVDC max), will these work. I also bought 4 .22 Poly Caps just in case.

if the 1.0 doesnt work, how do I connect the .22s...in series?

Thanks for all this great advice!
Doug

**brucek** · **09-11-07, 03:21 PM**

Quote:

I did buy 1.0 Tantalum caps (35WVDC max), will these work

Yep.........

brucek

**penngray** · **09-11-07, 03:23 PM**

quick reply, thanks.....

I havent done this in years so it will be fun, I hope I dont screw this up

**bobgpsr** · **09-11-07, 08:28 PM**

Quote:

penngray wrote:

Im about to mod my Cleanbox but I couldnt find any .47 caps at RS.

I did buy 1.0 Tantalum caps (35WVDC max), will these work. I also bought 4 .22 Poly Caps just in case.

if the 1.0 doesnt work, how do I connect the .22s...in series?

You have to observe the polarity with tantalum caps and also then have a ground return on the input. IIRC the + end should be to the inner box connection and the - end to the outside world (assuming a +V power supply IIRC). Then you really need a resistor (say 10K ohms) to ground at the input. Makes it a bit complex I know.

So it may be easier to use two 0.22 poly caps in parallel for a given input. You may only need to modify one channel's input (the used one) if you are lazy like me.

**penngray** · **09-12-07, 09:24 AM**

Quote:

You have to observe the polarity with tantalum caps and also then have a ground return on the input. IIRC the + end should be to the inner box connection and the - end to the outside world (assuming a +V power supply IIRC). Then you really need a resistor (say 10K ohms) to ground at the input. Makes it a bit complex I know

That would answer why I have horrible results currently. I hope I didnt destroy anything though.

Going back to the .22 caps in parallel and I only need to modify one channel since I only use one channel.

Advertisement