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Old 20th February 2006, 02:25 PM   #11
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Quote:
Originally posted by mazeroth
Do you guys think I could get away with using a receiver with 6 channel input, then using the 6 channel output from it to my amps? Or do you think that would be too much signal loss/degradation?
If the atenuation is done in the analog domain, you'll still keep the DCX in its best opperating range, however you will add noise from the receiver. So the noisier the receiver is the more you will distort the signal.. IMHO the best bet is to use amplifiers like the A500 with front mounted gain controls and use those for volume control...

Click the image to open in full size.

I just set the volume one time when I turn on my equipment and leave it alone, if you're the kind that constantly tweeks the volume, this may not be the best solution for you...

--Chris
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Old 21st February 2006, 03:40 PM   #12
tf1216 is offline tf1216  United States
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janneman:

Can you please elaborate more on the K5600? What do you think of the unit and its performance so far? How is it different than a Roland M1000?

sendler:

Scott, I love your stepped attenuators but if you want to change the volume, don't you have to change one for each channel? Isn't it tiresome?

Has anyone heard from bdipoala lately? I wanted to try some of his volume control techniques but we lost contact.

I think the Roland M1000 or bdipoala's design would be the route I would take. That is unless the K5600 can holds it own : )
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Old 21st February 2006, 03:51 PM   #13
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The problem with the M1000 is that the "level control", which I'm assuming is what you're using for volume control, is done in the digital domain. By usinging digital volume control you run into the same problem as using the DCX's built in level shift.. In order to get the most out of your digital bits you have to do the volume control in the analog domain after the DCX..

Regards,

--Chris
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Old 21st February 2006, 04:26 PM   #14
tf1216 is offline tf1216  United States
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Chris,

Thanks for the reply! I have read quite about about other people saying the same thing about the Roland M1000.

I have also have read that some people seem to think because the Roland M1000 upsamples or zero-pads the 16-bit code words to 24-bit code words, there is not loss in fidelity.

Both camps have their evidence to support their side so I guess I have to ask, have you heard the Roland M1000 before?

Please do not feel that I am calling you out, my apologies for that. I have contemplated purchasing one and would like to have some opinions from the 'ears' before I do so. Thanks!!

(Please exuse my DSP terminology, it has been a while since my latest class)
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Old 21st February 2006, 05:35 PM   #15
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I have not heard the roland 1000, I was simply reading about it on the internet.

Can you point me to where it mentiones the zero padding?
My thoughts on the zero padding are mixed. First of all thhis only helps if you feed it a digital signal with 16 bit precision, if you feed it analog and it samples at 24bits, you will loose the lowest level signals as soon as you start attenuating.
Assuming you feed it digital (would require alot of modifications to your DCX)

If it pads the MBS side of the 24 bit word that is :

output [15:0] = Input [15:0] and output[23:16] = 000000

Then this does nothing to help the problem, if you cut the volume you still loose precision.

If however they pad the lsb side :

output [24:6] = input [15:0] and output [5:0] = 000000 then you would be able to reduce the volume 2^5 without loosing any information or 64x electrical attenuation. This is a level of -18db from reference levels. As long as you keep the volume set above this level you will not loose any digital information, below this level you will start to loose bits at 1 bit per 3db attenuation. so at -30 db from reference you will loose 4 bits of information..

If you feed it analog, the sampling process spreads the information you generated fromm 16 bit data onto the 24bit codeword and therefore there is no "zero-padding", likewise if it "upsamples" instead of zeropadding it would digitally spread the 16 bit value onto 16 bits, and as soon as you attenuate it would drop the least significant bits..

Hope this helps,

--Chris
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Old 21st February 2006, 06:03 PM   #16
tf1216 is offline tf1216  United States
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Chris,

Haha, you were all over the thread I was looking for! There wasn't as much info in the thread as I thought!

Here it is anyway:

Behringer DCX 2496 to prototype active crossover

So what the heck is the best option for peeps who want volume control anyway?

Thank you for clearing up the confusion I had about the Roland M1000 and its DSP techniques!!

I checked out the Altronics OZ and it looks like it is $200. Is that right? Does it have to be built? Does it work in the analog domain after the Behringer equipment?

DCX->DEQ->volume control ????
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Old 21st February 2006, 06:25 PM   #17
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Quote:
Originally posted by tf1216
Chris,

Haha, you were all over the thread I was looking for! There wasn't as much info in the thread as I thought!

Here it is anyway:

Behringer DCX 2496 to prototype active crossover

So what the heck is the best option for peeps who want volume control anyway?

Thank you for clearing up the confusion I had about the Roland M1000 and its DSP techniques!!

I checked out the Altronics OZ and it looks like it is $200. Is that right? Does it have to be built? Does it work in the analog domain after the Behringer equipment?

DCX->DEQ->volume control ????
I believe you probably want to go (Source)->DEQ->DCX->Attenuators->Amps

This is my currenty setup, I'm trying to get a hold of an SRC2496 to add to the front of my signal chain for jitter reduction and digital upconversion..
Not sure if the upconversion will sound good or not, but I'd like to try it out

I still think the best method is to use passive attenuators on the outputs or gain controls on the amplifiers...

I was reading this article for my information..

http://www.soundonsound.com/sos/Jun0...olandm1000.asp

here is the quote I was basing my assumptions on : "The level control for each channel including the analogue one occurs in the digital domain with a range extending from unity gain all the way down to off."

--Chris
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Old 21st February 2006, 06:31 PM   #18
tf1216 is offline tf1216  United States
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Chris,

Thanks for the latest reply! So for us guys looking into volume control for our Behringer equipment, passive attenuators seem to be a far cry from economical and simple.

Example: During a listening session, the phone rings and the volume needs to be turned down. Does someone really have to adjust each passive attenuator separately? Where do people mount all of these?

A couple of my friends built me a 6-channel amplifier without active gain control. So I am also in desperate need of a volume control.
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Old 21st February 2006, 07:04 PM   #19
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Quote:
Originally posted by tf1216
Chris,

Thanks for the latest reply! So for us guys looking into volume control for our Behringer equipment, passive attenuators seem to be a far cry from economical and simple.

Example: During a listening session, the phone rings and the volume needs to be turned down. Does someone really have to adjust each passive attenuator separately? Where do people mount all of these?

A couple of my friends built me a 6-channel amplifier without active gain control. So I am also in desperate need of a volume control.
Its a tough call.. I recall some people using ganged-pots to do 3 and 4 channels at one time.. I guess you could try to use 2 3-channel pots one for each side or get a 6-channel pot somewhere. I haven't looked..

The other option is to make fixed attenuators -24db or so to set the maximum level of sound you realistically ever need. Then use your DCX or DEQ as a digital volume control (as minimum as possible to not loose precision).

RE: The phone call, thats what the "pause" button on your CD player is fore and I just use the "mute" buttons on the A/B input when I'm playing records...

--Chris
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Old 21st February 2006, 07:08 PM   #20
tf1216 is offline tf1216  United States
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Haha, I knew you would have some smart answer for my example! :

Thanks a ton Chris! Sorry for stealing the thread!!
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