New SAC Install for Headphone Band Mix - Questions

[cgrafx]

Hi All,

Ok... so I've installed SAC as an In Ear (except we all use Sony V6 headphones) System for band rehearsal. I had the system setup running 2-64 buffers but have also tried 2-128 and it didn't seem to make any difference.

What I'm hearing through the vocal mic (only my voice) is a phase shift. Not a discrete delay, but actual phasing of the audio.

Is this to be expected?

Anybody have suggestions on reducing the effect?

Do actual in ears exhibit this symptom? (its workable, but annoying)

I'm running a P4 3.2 GHz single processor system, RME HDSP 9562 and ADAs. The load is running between 12-18%.

[Bob L]

Make sure you do not have TotalMix also passing the input signals direct... you should start out with TotalMix set to preset 1... which generally drops all input faders down to -inf... if inputs are passing thru in the hardware DSP mixer, then you will hear a phasing or flanging sound as they mix with the SAC outputs x ms later.

Bob L

[cgrafx]

Make sure you do not have TotalMix also passing the input signals direct... you should start out with TotalMix set to preset 1... which generally drops all input faders down to -inf... if inputs are passing thru in the hardware DSP mixer, then you will hear a phasing or flanging sound as they mix with the SAC outputs x ms later.

Bob L

Yes, I thought of that. There is still sort of a swimmey/phasey (are those even words... lol) nature to the vocals.

I'll play with it some more and see if I can isolate anything specifically.

[averombri]

I intentionally delayed 9 miliseconds the 1-8 outputs of my LS 9-32,and nobody realiced of the stuff!,i'm concerned about using my SAC System with them and probably the phasy sound happens on in ears,nothing on wedges are noticiable,...umbeliable,the talents don't notice everything!

[brettbrandon]

Have you tried setting the buffer at 1-64 or 2-32? One of the reasons I rebuilt my host system was it would only achieve 3-128. We had the same problem but worse. What you are hearing is the time delay small as it may be. The reason you only hear it on your vocal is because you can hear your voice in your head without any amplification. And the headphones are recieving a signal a few ms behind the resonance in your head. I don't notice it anymore at 1-64. I should also mention that aplies only to in ear monitoring. You won't notice it in wedges.

[905shmick]

Maybe you're not getting enough latency!

Give this a read - http://www.whirlwindusa.com/wwlatart.html

[sjpaul]

Maybe you're not getting enough latency!

Give this a read - http://www.whirlwindusa.com/wwlatart.html

That made for interesting reading. I've just ordered IEM for remote soling purposes, but also planned to give them a try out when I'm performing and wondered what effect latency will have on the sound.

Also, given that my SAC system probably has about 5ms of delay built in, and the band's backline in most venues is about 15 feet from the front of the PA stacks, maybe I should be delaying my mains by 10ms?

[Wink0r]

That is sometimes done. I have done but I didn't really hear the difference. If you are in a club reflections probably kill most benefit anyway. Just try it and see if it works for you. I have talked to people that thought it was great.

[Bob L]

Just to make sure you are actually hearing latency between the acoustice sound of your voice and the signal thru SAC... mute the SAC chan and see if you still hear a vocal signal in the IEM... if so... you are passing a second signal from somewhere... this would be the cause of the real phase or flanged sound... two electronic signals blending with a slight delay between them... esentially a phaser or flanger effect.

Bob L

[cgrafx]

The latency article was definitely interesting reading.

I don't have any audio passing through the sound card directly. Everything is through SAC only.

I have to try inverting the signal and see if that makes a difference.

I'm not sure if my system will support 1x32, but I can try 1x64.

I did have the system at 2x64 and switched to 2x128 with little noticeable difference. (at least that I could hear).

I'll report back once I've had a chance to play around a bit.

thanks all for the information.

pg