ART Cleanbox frequency response

[fmw63]

What about the Aphex 124A? Cost quite a bit more than the CleanBox, but the specs look decent.
http://www.aphex.com/124A.htm
http://www.sweetwater.com/store/detail/124A/

Ilkka wrote:

"Slartibartfast" over at AV Talk forum has measured the SMS-1. I doubt the REW would show any different results but I can measure it when I get back home.

http://www.avtalk.co.uk/forum/index....&SQ=1182931696

Using the lowest setting...
-1.0 dB @ 20 Hz
-11.5 dB @ 10 Hz
-29 dB @ 5 Hz

So actually it's even worse than the Art Cleanbox...

That's scary. Has anyone done similar testing with a BFD?

[Ilkka]

Luke G wrote:

That's scary. Has anyone done similar testing with a BFD?

Yes, the BFD is much better.

-0.6 dB @ 20 Hz
-1.1 dB @ 10 Hz
-2.5 dB @ 5 Hz
-7.2 dB @ 2 Hz

Here's a comparison.

[JimP]

Ikka,

Can you throw in the SMS-1 into that chart?

Thanks

[Ilkka]

JimP wrote:

Ikka,

Can you throw in the SMS-1 into that chart?

Thanks

I can, but not until I get back home (around two weeks).

edit: See below.

[Nick77]

SteveCallas wrote:

Another one bites the dust and another valuable piece of real world info from Ilkka. Now imagine if someone was using a Velo SMS with an Art Cleanbox in the chain coming from a HK receiver......wow, instant HTIB subwoofer

Steve I missed previous input about HK recievers. Please give me a brief reply on findings since I am running a 635. Thanks

[brucek]

I missed previous input about HK recievers. Please give me a brief reply on findings

Ever used REW software Nick? You could check your own receivers response fairly easily.

brucek

[SteveCallas]

Nick77 wrote:

Steve I missed previous input about HK recievers. Please give me a brief reply on findings since I am running a 635. Thanks

If the EQ settings are used at all, a highpass filter is automatically engaged based on the description of the subwoofer. There should be an option menu that asks how large of a subwoofer driver you are using, and the largest choice is a 15". I forget the specific center frequencies of the highpass for each driver size, but they were all too high for a LLT.

As long as you leave the EQ feature off, I think you will be ok.

[NickTF]

This is something I posted on AVS Forum after reading this thread. Can someone advise pleas? Thanks and happy 4th to everyone!

Ok, was just browsing through and saw what the Art Clean box does to the FR and considering i'm using this for a subwoofer application -5.4db at 20hz etc. is not exactly desireable. So my question now becomes can I just hook the QSC PLX3602 up directly to the LFE line level output of my reciever by using either a RCA to XLR or RCA to TRS jack?

My reciever is a Pioneer 1015TX in which the manual indicates output specs on the RCA connections of 335mv and 2.2 k-ohms. The input sensitivity of the PLX3602 is listed as 1.25 volts rms and 10k-ohms unbalanced and 20k-ohms balanced. Will this work? Any advice is appreciated.

[brucek]

My receiver is a Pioneer 1015TX in which the manual indicates output specs on the RCA connections of 335mv and 2.2 k-ohms. The input sensitivity of the PLX3602 is listed as 1.25 volts rms and 10k-ohms unbalanced and 20k-ohms balanced. Will this work?

Yes, it will work. I suggest that the spec from the pioneer of 335mvolts is the nominal output and indicates the standard consumer nominal level of -10dBV (which is ~316mvRMS). The normal maximum output of that interface would then likely be a standard +2dBV (which is 1.26mvRMS). That is consistent with the maximum spec you list for the PLX3602. Just make up your RCA to TRS (or XLR) connector and you'll be fine..

brucek

[NickTF]

brucek wrote:

Yes, it will work. I suggest that the spec from the pioneer of 335mvolts is the nominal output and indicates the standard consumer nominal level of -10dBV (which is ~316mvRMS). The normal maximum output of that interface would then likely be a standard +2dBV (which is 1.26mvRMS). That is consistent with the maximum spec you list for the PLX3602. Just make up your RCA to TRS (or XLR) connector and you'll be fine..

brucek

Thanks! I will probably just go pick up an adapter from radio shack. I don't know if they have RCA to XLR but i'm 99% sure they have RCA to 1/4" TRS so that's the way i'll go.

[brucek]

Thanks! I will probably just go pick up an adapter from radio shack. I don't know if they have RCA to XLR but i'm 99% sure they have RCA to 1/4" TRS so that's the way i'll go

You would need an RCA to TS adapter to convert to unbalanced......



brucek

[NickTF]

brucek wrote:

You would need an RCA to TS adapter to convert to unbalanced......



brucek

Yep, that's the one, thanks!!!

[Chrisbee]

I couldn't get XLR to RCA despite trying 5 music shops so finally had to settle for male and female XLR to female Jack adaptors then male Jack to RCA adaptors.

Here's the CX2310 active crossover frequency response.
Low frequency channel: Crossover set to 930Hz max (X1). All gain settings to flat.

Not much to worry about here:

[brucek]

Not much to worry about here

Yeah, very good. It seems most of the Behringer stuff has excellent low frequency response..

brucek

[Chrisbee]

I'm just grateful the CX2310 wasn't stealing my bass.

[brucek]

What would be the downside, if any, of simply using one an EQ band or shelf filter

I don't see a lot of down side. The mod to the cleanbox seems fairly simple though and even with the rudimentary tests that a few performed, it appears effective. I believe Ilkka said he would test the mod properly when he has the time, and then you could get a better idea if it was worth the effort.

brucek

[bobgpsr]

DS-21 wrote:

I probably phrased my post badly. More succinctly, what I meant to ask was the following: what is the downside (if any) of leaving the Cleanbox as is and simply ensuring low-end response to taste via downstream EQ?

Worse Signal to Noise ratio due to loss in the Cleanbox. Better to fix the low frequency rolloff issue in the Cleanbox and not lose the real signal. Also downstream eq would be rare -- what would do it? The Cleanbox is meant to just bring the line level up to pro audio level and have a balanced output (to drive a pro amp). Would really need a pro type equalizer.

A BFD already has an input selection for consumer level line inputs -- Cleanbox should not be needed at all with it.

[Ilkka]

Here's a little something I put together.

Frequency responses are levelled at 100 Hz except for SMS-1 and R-DES which don't have a fully by passable low pass filter. The SMS-1 had the newest v2.12 software and 5 Hz, 6 dB/oct. subsonic filter setting was used. DSP1124P is known as the older BFD (though not the oldest which is the DSP1100), and FBQ2496 is known as the newer BFD, which seems to have the least low frequency roll-off of them all. I will soon mod the Cleanbox to find out if that improves it.

[Mongrel714]

Since I'm using a pro amp I'm gonna try a pro direct box and see how that works, if it seems to do the job we'll measure this thing and see if it is an option.

[Chrisbee]

Thankyou for sharing this graph, Ilkka.

How important, in your experience, is the bass roll off of these boxes in the real world?

Do these roll-offs just offer valuable protection to modest subwoofers?

Presumably the effect is very subwoofer dependent?

If a sub can't reach low and loud then it won't notice the high pass effect anyway.

[Blaser]

I'm happy to have dual RL-P18 in 650 L each and a FBQ2496

[Ilkka]

"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).

[Ilkka]

Chrisbee wrote:

Thankyou for sharing this graph, Ilkka.

How important, in your experience, is the bass roll off of these boxes in the real world?

Do these roll-offs just offer valuable protection to modest subwoofers?

Presumably the effect is very subwoofer dependent?

If a sub can't reach low and loud then it won't notice the high pass effect anyway.

Well naturally one doesn't have to be worried about this all if his sub goes only down to 30 Hz. But if one is after a good output down to 10 - 15 Hz or lower, I would definitely think which EQ to choose. And yes, one easily gains some or actually quite a lot of (excursion) protection with some of these models. But that's actually pretty old news to most of us...

Any kind of filtering (low or high pass) of course always adds group delay, though that's pretty much the least thing one should be worried about at these frequencies.

[Chrisbee]

Thanks, Ilkka.