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Hiss using AES conection instead of Analouge

louis-enslin, modified 7 Years ago.

Hiss using AES conection instead of Analouge

Youngling Posts: 9 Join Date: 2/5/14 Recent Posts
HI
I have been using my 3 L C R 8260A with an analouge feed from my Protools setup through my Dangerous audio monitoring system for almost a year now. I ran a smaller Analouge SUB and recently upgraded to the 7271A Sub.
That being an AES only sub, I got the Genelc 8 channel analouge to AES converter and just ran the Sub feed from my system through it to drive the sub. So far everything is working ok, but I need to "ring ' the room, so I decided to run the LCR speakers throught the Analouge to AES converter as well, and run a complete Digital speaker setup and Calibrate my room with GLM.
The problem I have is, as soon as I connected the AES feed thought the A-D and SUB, I get quite a loud HISS through the 8260A's. Everyhting works from a an audio point of view, sound comes out and sounds corret, but it hisses?
Any ideas why? I use proper AES cable etc.
Thanks for your help
Louis
ilkka-rissanen, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Hi,

During the first minute after turn-on the noise level is high and decreases during this time. The noise level of the AD converter is slightly higher than that of the AES inputs.
louis-enslin, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Youngling Posts: 9 Join Date: 2/5/14 Recent Posts
HI Ilkka

Just to make I understand you correctly.

You say that I should leave it for a couple of minutes. And that during this time the hiss will get softer? How long, a couple of minutes, hours?

And then, do you mean that the Genelec A/D stand alone converter is noisy? Should I try a diffrent brand of converter to see if I get the same result?

When I did the AES conection yesterday, I played music through all the speakers Panning etc to make sure that the channel assignments are correct, so the system was probably running for about 3 minutes, and the noise level did not change.

I'll try to BYPASS the Sub in the signal chain, so go directly from the Genelec A/D converter to the LCR speakers and see. Maybe the Sub is adding noise?

Thanks
louis-enslin, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Youngling Posts: 9 Join Date: 2/5/14 Recent Posts
Also, not sure if this will help, but I wired my setup according to page 11 and 12 of the Sub Menu
Thanks
louis-enslin, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Youngling Posts: 9 Join Date: 2/5/14 Recent Posts
Is this connection Im doing correct?

This is how I connect to the AD9200A

Left Analouge feed - Analouge in 1 - AES Out 1 - AES Sub in 1 - AES Sub out 1 - L speaker AES in

Right Analouge feed - Analouge in 3 - AES Out 2 - AES Sub in 2 - AES Sub out 2 - R speaker AES in

Center Analouge feed - Analouge in 5 - AES Out 3 - AES Sub in 3 - AES Sub out 3 - C speaker AES in

LFE Analouge feed - Analouge in 7 - AES Out 4 - AES Sub in 4

My surround channels go directly to 2 KRK VXT8's. Analouge in

Is this setup correct?
Thanks
ilkka-rissanen, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
HI Ilkka

Just to make I understand you correctly.

You say that I should leave it for a couple of minutes. And that during this time the hiss will get softer? How long, a couple of minutes, hours?

Warm-up time is less than a minute. During this time the noise level will stabilize.


And then, do you mean that the Genelec A/D stand alone converter is noisy? Should I try a diffrent brand of converter to see if I get the same result?

The noise level of the AD converter is slightly higher than that of the AES inputs.


When I did the AES conection yesterday, I played music through all the speakers Panning etc to make sure that the channel assignments are correct, so the system was probably running for about 3 minutes, and the noise level did not change.

Noise level will stabilize during the first minute after a cold start. You shouldn't experience any change after 3 minutes.


I'll try to BYPASS the Sub in the signal chain, so go directly from the Genelec A/D converter to the LCR speakers and see. Maybe the Sub is adding noise?

Thanks

You may try this, but the subwoofer is not adding noise.
louis-enslin, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Youngling Posts: 9 Join Date: 2/5/14 Recent Posts
HI Ilkka
Thanks, I had a gap and tried diffrent conection options, also switich the back of the speakers to only read AES channel a or B. But no change. Also I shut down whole system, and reconected everything, and played music for about 10 minutes, and the noise level did not stabalise. Its not very loud, but Im abount 3 meters away from them, and its quite audible, especially with the L, C and R speakers all emiiting the same hiss constantly. I would undertand if the spearkers self noise has a bit of hiss, which they do, but the AES compared to the Analouge in is A LOT.

Im considering to run the L C R with analouge ins, and the only the SUB through a A/D converter. But I was told that Auto cal wont work then? Is it absolutely necesary for me to run the speakers through the Sub first, for Auto Cal to work?

last resort is I need to exchange this SUB with the version with the Analoug ins as I cant work work with the constant Hiss in the AES side, especially not mixing music with soft pasages?
Please advise

thanks for your help
Louis
ilkka-rissanen, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Is this connection Im doing correct?

This is how I connect to the AD9200A

Left Analouge feed - Analouge in 1 - AES Out 1 - AES Sub in 1 - AES Sub out 1 - L speaker AES in

Right Analouge feed - Analouge in 3 - AES Out 2 - AES Sub in 2 - AES Sub out 2 - R speaker AES in

Center Analouge feed - Analouge in 5 - AES Out 3 - AES Sub in 3 - AES Sub out 3 - C speaker AES in

LFE Analouge feed - Analouge in 7 - AES Out 4 - AES Sub in 4

My surround channels go directly to 2 KRK VXT8's. Analouge in

Is this setup correct?
Thanks

That should work just fine, but typically we recommend to use AES/EBU single-wire connection, according to subwoofer operating manual, page 9.

Left Analogue feed - Analogue in 1 - AES Out 1 - AES Sub in 1 - AES Sub out 1 - L speaker AES in (subframe A)

Right Analogue feed - Analogue in 2 - AES Out 1 - AES Sub in 1 - AES Sub out 1 - R speaker AES in (subframe B)

Centre Analogue feed - Analogue in 7 - AES Out 4 - AES Sub in 4 - AES Sub out 4 - C speaker AES in (subframe A)

LFE Analogue feed - Analogue in 8 - AES Out 4 - AES Sub in 4 (subframe B)
ilkka-rissanen, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
HI Ilkka
Thanks, I had a gap and tried diffrent conection options, also switich the back of the speakers to only read AES channel a or B. But no change. Also I shut down whole system, and reconected everything, and played music for about 10 minutes, and the noise level did not stabalise. Its not very loud, but Im abount 3 meters away from them, and its quite audible, especially with the L, C and R speakers all emiiting the same hiss constantly. I would undertand if the spearkers self noise has a bit of hiss, which they do, but the AES compared to the Analouge in is A LOT.

I am sorry to say but this is the normal noise level of the AD converter. It may be audible at 3 meters if the background noise level of your room is low.


Im considering to run the L C R with analouge ins, and the only the SUB through a A/D converter. But I was told that Auto cal wont work then? Is it absolutely necesary for me to run the speakers through the Sub first, for Auto Cal to work?

AutoCal will work just fine but the LCR won't be bass managed then which is a problem because the operating bandwidths of them and the subwoofer will overlap. If you have another device to make a crossover between them, it would work.


last resort is I need to exchange this SUB with the version with the Analoug ins as I cant work work with the constant Hiss in the AES side, especially not mixing music with soft pasages?
Please advise

This would be an option, but of course then the subwoofer bandwidth (below 85 Hz) wouldn't be AutoCalibrated.

May I ask why you need a subwoofer in a system having 8260As in LCR? Their frequency response goes (typically) below 20 Hz after AutoCal. Do you use such high SPL that the output capability isn't high enough or what is the reason?
louis-enslin, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Youngling Posts: 9 Join Date: 2/5/14 Recent Posts
Hi Ilkka
Thanks for the replies.

I'll see what the best way forward is. to answer your question. I have a sub in the sustem for 5.1 work. I need the sub for the LFE Channel. And currently I cant afford Genelec Ls and RS speakers so I have my old KRK's for that.

I dont realy mix normal stereo material with Sub on, I only use that doing 5.1 work. So I might just run Auto Cal with the L C R speakers. to make sure they are calibrated for the room. And atuo cal the sub to make sure the Phase as correct and in line with the LCR's and only use the sub when doing 5.1 work.
Thanks again
Louis
ilkka-rissanen, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Hi Louis,

One possible solution would be to lower the GLM volume level from maximum 0 dB to for example -10 dB or -15 dB of full scale. This usually brings any remaining noise level to insignificant level without limiting the maximum sound pressure level and the input signal to the AD converter can be set higher. If the GLM volume control is pushed to the max, then the user usually ends up pulling down the input level to compensate, then the dynamic range of the AD converter is not fully utilized, and also the idle channel noise level goes up.
louis-enslin, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Youngling Posts: 9 Join Date: 2/5/14 Recent Posts
Hi Ilkka
Cool, This might work. I'll give that a try!
louis-enslin, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Youngling Posts: 9 Join Date: 2/5/14 Recent Posts
Sorry
One more question, Do I need to buy the GLM software?
Thansk
ilkka-rissanen, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Sorry
One more question, Do I need to buy the GLM software?
Thansk

You need the GLM package which contains the interface, microphone and software. Order code 8200-601C, price 618 EUR (ex. VAT). You can also download the software from http://www.community.genelec.com/software/ but it works only in demo mode without the interface.
louis-enslin, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Youngling Posts: 9 Join Date: 2/5/14 Recent Posts
Thanks Illkka

Will the Demo mode be able to controll the level to see if thats a feasable option, or will I not be able to controll the volume without the Network interface?
Thanks
ilkka-rissanen, modified 7 Years ago.

Re: Hiss using AES conection instead of Analouge

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
The demo mode won't have any actual control over the system/speakers. It is only for demonstration purposes.

It is also possible to reduce the volume using the level controls on the back side of each speaker. Please look at the operating manual for more information.