Problem with Genelec AIW26 noise/hiss

[MidnightSensi]

A friend of mine put in Genelec AIW26 inwall speakers:

http://www.genelec-ht.com/architectural/aiw26/

They are inwalls with little amps post-crossover.

He called me over because he was having some problems getting them setup with his installer.

He is running through a Denon 3808 > Unbalanced RCA into the balanced XLR > Genelec RAM1 amps > Genelec AIW26 speakers.

I think the output of the Denon 3808 preouts isn't enough for the inputs on the Genelecs to drive them to full power. So it ends up getting cranked, and the noise floor is high. That's his complaint. His installers came out and tried to fix it, and didn't, so now he asked me, and now you.

What do you guys think the problem is? Am I on the right track? And, if so, what's the most elegant way to boost consumer signal to a pro level like the genelecs perhaps like? It's like the line level isn't strong enough. How do I figure out if the RAM1 amp can be driven enough by a Denon 3808?

 

[bandphan]

http://www.sweetwater.com/store/detail/CleanBox/

 

[Ilkka]

What do you guys think the problem is? Am I on the right track? And, if so, what's the most elegant way to boost consumer signal to a pro level like the genelecs perhaps like? It's like the line level isn't strong enough. How do I figure out if the RAM1 amp can be driven enough by a Denon 3808?

Hi,

I would recommend checking the signal cable wiring first. Be sure that the RCA to XLR connection is done according to the following instructions (up-most picture): http://www.genelec.com/faq/applicable-to-all-models/unbalanced-outputs/

If everything is good there, the most probable reason for the higher than normal background noise level is a ground loop and/or other induced noises from the system. This is a problem sometimes when ungrounded and unbalanced Hi-Fi devices are connected to grounded and balanced Pro devices. It is not because of the nominal signal voltage difference.

To cure this problem an active balancer is required: http://www.genelec-ht.com/products/di8a/ It will break the ground loops and also boost the signal level.

I would not recommend using devices such ART CleanBox because they can actually cause additional problems. For example the CleanBox is tested to have a large bass attenuation problem: http://www.hometheatershack.com/forums/diy-subwoofers/5282-art-cleanbox-frequency-response.html

Best regards,
Ilkka
Genelec R&D

 

[Warpdrv]

Ilkka

Nice of you to stop here, I see you have been posting more here... great to see info and support about some of Genelec's less then known products... **edit** just saw the price on that unit - wowsers..

That looks like a great unit, which would solve problems for a good deal of people, I had issues such as this when using a receiver as a pre-amp to a balanced amp - noise induced. After moving to a Balanced Pre-amp to my Balanced amp I found all the noise issues were gone...

Thanks for supporting Genelec here on Audioholics, always learned alot from you, and you are part of the reason I'm broke - (LMS's & Amps )

 

[MidnightSensi]

Hi,

I would recommend checking the signal cable wiring first. Be sure that the RCA to XLR connection is done according to the following instructions (up-most picture): http://www.genelec.com/faq/applicable-to-all-models/unbalanced-outputs/

If everything is good there, the most probable reason for the higher than normal background noise level is a ground loop and/or other induced noises from the system. This is a problem sometimes when ungrounded and unbalanced Hi-Fi devices are connected to grounded and balanced Pro devices. It is not because of the nominal signal voltage difference.

To cure this problem an active balancer is required: http://www.genelec-ht.com/products/di8a/ It will break the ground loops and also boost the signal level.

I would not recommend using devices such ART CleanBox because they can actually cause additional problems. For example the CleanBox is tested to have a large bass attenuation problem: http://www.hometheatershack.com/forums/diy-subwoofers/5282-art-cleanbox-frequency-response.html

Best regards,
Ilkka
Genelec R&D

Cheers for the response.

The cables are connected correctly and ground loops have been eliminated. It's more of a hiss than a hum, just amplifier hiss. Lowering the high shelf dip switch on the amplifier helps some, but I just plain think the amplifiers gain needs to come down and needs more input voltage to drive it.

To test this, I connected a Vestax mixer with balanced outputs. The gain on the RAM amps could be turned way down, and with that the hiss went way down. The speakers sounded great.

So, the output sensitivity of the Denon still seems to be a bit low for the Genelec RAM amplifiers. I may need to use a balancing product, although I hate to have to tell my friend who just spent all that on these speakers that he needs to buy additional equipment to make it work right.

What are the sensitivity of these monitors?

Thanks again

 

[KEW]

Double check me on this, but I believe a product like the Behringer DCX-2496 will get you the RCA in to Balanced out conversion/gain as well.
Just a thought in case you were considering EQ - kill two birds...

 

[MidnightSensi]

Double check me on this, but I believe a product like the Behringer DCX-2496 will get you the RCA in to Balanced out conversion/gain as well.
Just a thought in case you were considering EQ - kill two birds...

Cheers. I have some dbX direct boxes that I might try, but, it looks like the Genelec box is the right way to do it. I just didn't know if there was a way to boost output voltage without adding another box, like maybe a setting in the Denon or something. It has levels, but, I can't find anything like a -10/+2 setting or anything.

Considering he spent like $20,000 in Genelec products, ones that were advertised as for home theater use (most of which use unbalanced connections), I might call and see if they'll send him that box on the house.

As far as EQ, the RAM amplifiers have some response tilt switches that take the response, and the Denon has Audyssey. I took some measurements and was able to get pretty good response with just the dip switches.

 

[Ilkka]

Thanks for supporting Genelec here on Audioholics, always learned alot from you, and you are part of the reason I'm broke - (LMS's & Amps )

Hi,

My pleasure.

 

[Ilkka]

Cheers for the response.

The cables are connected correctly and ground loops have been eliminated. It's more of a hiss than a hum, just amplifier hiss. Lowering the high shelf dip switch on the amplifier helps some, but I just plain think the amplifiers gain needs to come down and needs more input voltage to drive it.

To test this, I connected a Vestax mixer with balanced outputs. The gain on the RAM amps could be turned way down, and with that the hiss went way down. The speakers sounded great.

So, the output sensitivity of the Denon still seems to be a bit low for the Genelec RAM amplifiers. I may need to use a balancing product, although I hate to have to tell my friend who just spent all that on these speakers that he needs to buy additional equipment to make it work right.

Output voltage of the Denon isn't the issue because even if it would be too low, it would only present itself as lower than expected maximum SPL of the AIW26s, not hiss. Hiss from the speakers means that the input signal to the AIW26 amplifiers isn't clean, i.e. the noise level is higher than it should be. It will require some detective work to figure out what's causing it. I would start by unplugging everything but he mains from the Denon, and then cable by cable connecting back again to find out the point where the hiss is induced to the signal. How are the channel level settings on the Denon?

Since the AIW26 amplifier has also unbalanced RCA input, you could try if using that makes any difference?

What are the sensitivity of these monitors?

Thanks again

I'll save some typing by giving you this link: http://www.community.genelec.com/forum/viewtopic.php?f=4&t=130

 

[MidnightSensi]

Output voltage of the Denon isn't the issue because even if it would be too low, it would only present itself as lower than expected maximum SPL of the AIW26s, not hiss. Hiss from the speakers means that the input signal to the AIW26 amplifiers isn't clean, i.e. the noise level is higher than it should be. It will require some detective work to figure out what's causing it. I would start by unplugging everything but he mains from the Denon, and then cable by cable connecting back again to find out the point where the hiss is induced to the signal. How are the channel level settings on the Denon?

I'll save some typing by giving you this link: http://www.community.genelec.com/forum/viewtopic.php?f=4&t=130

Last night I connected a set of Rane BB44X balancers I had around. The speakers are now silent because I was able to turn the amplifier gain down. I only had two, so the rears didn't get treated, but I will look into either buying the Genelec box or something else.

If I disconnect the amplifiers from the Denon, the hiss is still presents. It's amplifier noise. The reason I was asking for the driver sensitivity is if they are very sensitive then typically the noise floor is a bit higher at 'idle.' If that's the case, the owner will just have to deal with it. I've gotten it to where the noise is pretty low with the Rane boxes, I think the owner just expected it to be silent. His speakers before were 86db/w sensitivity, and were completely silent.

The channel level settings on the Denon are at +3 for the fronts and unity for the rears.

Cheers for all the help, greatly appreciated.

 

[Ilkka]

Last night I connected a set of Rane BB44X balancers I had around. The speakers are now silent because I was able to turn the amplifier gain down. I only had two, so the rears didn't get treated, but I will look into either buying the Genelec box or something else.

If I disconnect the amplifiers from the Denon, the hiss is still presents. It's amplifier noise. The reason I was asking for the driver sensitivity is if they are very sensitive then typically the noise floor is a bit higher at 'idle.' If that's the case, the owner will just have to deal with it. I've gotten it to where the noise is pretty low with the Rane boxes, I think the owner just expected it to be silent. His speakers before were 86db/w sensitivity, and were completely silent.

The channel level settings on the Denon are at +3 for the fronts and unity for the rears.

Cheers for all the help, greatly appreciated.

Okay, now it's starting to untie. I was under the impression that the noise was present only after connecting the Denon to the Genelec amplifiers. If the Genelec amplifiers cause any noise, with their signal cables unconnected, that is clearly audible from further than ~1-2 feet from the speakers, they need service. I will be in contact with our USA subsidiary asap.

While waiting for that, you might try them with a different speaker cable. It shouldn't make any difference, but it's always good to double check.