New Project: Chop top LS with Double Stack ESS AMT-1

[Pete H]

40 minutes ago, Rudy81 said:

Yes, the leads are too short for our stack.  What I did was to solder extra wire to the leads to make them plenty long.  I also used red/black wiring to make the connections make standard.

First thing I did was solder and shrink wrap extension wires on.

 

[Thaddeus Smith]

1 minute ago, Pete H said:

First thing I did was solder and shrink wrap extension wires on.

 

 

[Thaddeus Smith]

So for the past two months Morgan has been complaining about the Yamaha club speakers I've had in place while the new setup was being worked on. Even unfinished with basic XO's she's very much impressed with the new sound as they've spent the morning using the speakers. So there's that, instant WAF.

[Marvel]

Those cabinets look awesome in that room!

[Thaddeus Smith]

1 hour ago, Marvel said:

Those cabinets look awesome in that room!

 

Everything is mashed together and not optimal, but there's a long term plan here. We'll be building a new house on our property in the next 5-7 years and I'll have a dedicated space at that time where I can bring them out into the room, further apart, etc. I'll see how the paint holds up in the meantime and repaint/tweak as needed then.

[Thaddeus Smith]

5 hours ago, Thaddeus Smith said:

This is no doubt learning curve related. I  do have a low but constant "shhhhhhhhh" noise in the HF drivers. Audible when nothing is playing, less so when there's content. Muting input signals and output in the Yamaha doesn't change the behavior and the loudness doesn't change with volume up or down. Trim levels in the AVR are 0, as are the input and output levels in the Yamaha. I suspect I need to play with some gain matching. It's not electrical hum, of that I am sure.

 

4 hours ago, CECAA850 said:

Yes, that's gain related.

 

Right. I've read through an earlier linked guide on gain structure, so indulge me as I think out loud. Currently I have the gain up only a couple of notches on the amp. I temporarily had the AVR connected directly to the amp with the gain increased on the amp and it was silent. Since the noise is there when no content is playing and isn't variable with the AVR volume, it doesn't seem like I need to modify trim levels in the AVR.The yamaha DSP has level controls for both the input and output signal, but again it doesn't seem like input signal is the problem.

 

So that leaves output levels in the DSP.. turn that down and then turn up the amp gain to achieve my 75-85dB SPL "normal"?

 

There's an element of "try it and see Michael," but I'm hoping to lean on collective experience to reduce the number of permutations I should be trying with 5 different methods of controlling the sound level coming out of the speakers, especially since the 6 independent drivers are being fed by the same Main L/R input channels.

[CECAA850]

1 minute ago, Thaddeus Smith said:

turn that down and then turn up the amp gain to achieve my 75-85dB SPL "normal"?

I would try that next yes.  Remember, the amp is amplifying what it receives.

[rplace]

4 minutes ago, Thaddeus Smith said:

There's an element of "try it and see Michael," but I'm hoping to lean on collective experience to reduce the number of permutations I should be trying with 5 different methods of controlling the sound level coming out of the speakers, especially since the 6 independent drivers are being fed by the same Main L/R input channels.

 

You have a 2-way system now with Left HF/LF and Right HF/LF, right?

 

I'd either mute the inputs one at a time or the HFs and LFs and see where the noise is coming form if simply putting your ear close to each does not tell you which is offending.

 

I don't have gain control on my HF section's amps but I do on the LF. I put the LF amp's gain up to about 75-80%, adjust with DSP to get HF and LF even then control the overall volume with preamp. Hmmmm, just reread about the AVR part so not quite the same. Is the AVR your amplification for all drivers?

[Thaddeus Smith]

1 minute ago, rplace said:

 

You have a 2-way system now with Left HF/LF and Right HF/LF, right?

 

I'd either mute the inputs one at a time or the HFs and LFs and see where the noise is coming form if simply putting your ear close to each does not tell you which is offending.

 

I don't have gain control on my HF section's amps but I do on the LF. I put the LF amp's gain up to about 75-80%, adjust with DSP to get HF and LF even then control the overall volume with preamp. Hmmmm, just reread about the AVR part so not quite the same. Is the AVR your amplification for all drivers?

 

Technically 3-way? I'm running my mains and subs through the yamaha DSP from the AVR's Main L/R pre-outs - trying to avoid the AVR processing entirely for more granualar control. All 3 amps are the same and have per-channel gain control. I can hear the noise coming from the Heils from my MLP as well as with an ear on them.

[CECAA850]

14 minutes ago, Thaddeus Smith said:

try it and see Michael,

If you go that route, there probably aren't that many combinations to try.  Get a pad and jot down what you try along the way.  You'll avoid repetition and possibly notice patterns.

[Thaddeus Smith]

Just now, CECAA850 said:

If you go that route, there probably aren't that many combinations to try.  Get a pad and jot down what you try along the way.  You'll avoid repetition and possibly notice patterns.

 

Again, you're not wrong.

[rplace]

40 minutes ago, Thaddeus Smith said:

All 3 amps are the same and have per-channel gain control. I can hear the noise coming from the Heils from my MLP as well as with an ear on them

 

If you have not already tried it, I'd say turn the gain on the amps to the AMTs up to about 75-80% and use the Yamaha to get them to the level you need to balance them with LF. Finally use the AVR for volume control as usual. In a nut shell Amps fixed to a high-ish level and knocked back with DSP to "reasonable" and preamp/AVR for listening session adjustments.

[Thaddeus Smith]

From my amplifier's manual:

 

Quote

Attenuators - Range is 0 dB to -infinity; vertical is -10 dB. Amplifier
sensitivity is 4 dBu with attenuator at 0 dB and 14 dBu at -10 dB.

 

 

I currently have it 3 stops from the -infinity mark, so about 10 o'clock.

 

And then the output controls on the yamaha show this range of -infinity to +10. It's good that things are standard in the pro space...

 

[ClaudeJ1]

12 hours ago, Thaddeus Smith said:

This is no doubt learning curve related. I  do have a low but constant "shhhhhhhhh" noise in the HF drivers. Audible when nothing is playing, less so when there's content. Muting input signals and output in the Yamaha doesn't change the behavior and the loudness doesn't change with volume up or down. Trim levels in the AVR are 0, as are the input and output levels in the Yamaha. I suspect I need to play with some gain matching. It's not electrical hum, of that I am sure.

It's possibly the "twin peaks" at 5 and 10 Khz. as the culprit. If not, use a 20K potentiometer ahead of the power amp to knock down the voltage and cause a higher signal to noise ratio from your line source.

[Thaddeus Smith]

The drivers are practically silent just two notches from -infinity and channel output levels at 0 in the yamaha. I did switch from the 70 v mode to low-z mode, which definitely helped. So maybe it's just a factor of these fairly flexible class D amps and that they don't follow common "norms" with regard to gain control. It seems like I still have plenty of wiggle room with output trim in the DSP to gain match the individual drivers while maintaining a low noise floor.

 

[billybob]

32 minutes ago, ClaudeJ1 said:

It's possibly the "twin peaks" at 5 and 10 Khz. as the culprit. If not, use a 20K potentiometer ahead of the power amp to knock down the voltage and cause a higher signal to noise ratio from your line source.

Supposing you are saying this to attenuate gain...

 

[Thaddeus Smith]

Definitely still tinkering and thinking out loud here while I do. I was able to bump the gain on my HF amp channels a bit more while setting the Yamaha output levels back to 0 and now I have to put my ear right at the drivers to hear the noise floor. So, getting in better shape and that switch from 70 v to Low-Z definitely made the biggest impact.

 

From a sound quality perspective, everything sounds really good.. amps, drivers, etc. No electrical hum or RF noise - so all of the interconnects are solid as are the individual components in the signal chain.. it's just a matter of dialing things in. I've gotten really good at getting Audyssey to deliver reasonable results over the last decade so it's just a steep learning curve now that I have everything in front of me with more granular control.

[Marvel]

You wouldn't want to use the 70v output. That's for systems like a group of ceiling speakers and distributed audio. The speakers would have transformers on them with taps to set their volume.. you should be using 4/8 ohms outputs.

[ClaudeJ1]

4 hours ago, billybob said:

Supposing you are saying this to attenuate gain...

 

Yes and no. I'm Increasing Gain with the first and quietest device. Pro Gear uses XLR connectors and the signal levels are much higher than stuff for home.  So we need to use that higher voltage to our advantage up to 8 volts. The higher the nominal operating voltage from the source, the higher the signal to noise ratio. This was the operating principle used in Dolby Noise Reduction for Cassette Tapes. But it was limited to the high frequencies...........boost the treble in recording and cut in the playback electronics. This is a full band adaptation of the same principle. Let the signal ride up above all the noise, then the Passive (usually 20 Kohms) Potentiometer knocks it back down to a level that is more palatable by the Power Amplifier while feeding an inherently lower noise floor, since the whole thing gets lowered with lowering the too high voltage in the signal. Plus you get to use all the high bits in the Yamaha to full advantage.

[billybob]

Thanks for your detailed response.