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Discussion Starter · #1 ·
Alright, so last night I started doing some gain structure setting and got into some weird results.

First off, I’m using a Pioneer p9 headunit and an alpine h071 processor right now, with the c701 for setting things up.

I used 0db test tones at various frequencies and an oscilloscope.

I first tested the p9 and found that it doesn’t clip at max volume. Now I can use this as my basis to work downstream.

My findings:
1. H701 goes bananas with a 4khz tone until I back the headunit volume down to -06dB. As soon as I hit -05dB it goes apeshit squarewaves, then I back it down one click and it's fine.
2. This is only with tones 4khz and below. 8khz doesn't give this problem at all.
3. This is true for tweeter and midrange channels. Imagine the same for the others.

I took a break to eat and then came back for more testing.
What I found was this:
I can put the c701 volume up to 35 and get a max volume on the headunit of -09dB. Using a 40hz, 0dB tone. As I go higher I max out at -06dB for 1khz and 4khz tones. 8khz doesn’t give me any problems at all.
I get in the car, listen to the cd player paused so I can listen for hiss with the c701 volume. ALL gains on ALL amps set at bare minimum to rule out amps' noise floor. Hiss starts at 23 on the c701. So, that's my cutoff point for the c701 volume.

Get out of the car. Set headunit volume to 0dB (max, and unclipped). Set c701 volume to 23 (max un-noisy volume). Unplug all outputs from h701 and start testing again.
At this point the highest volume I can go to is -06dB, following this:
@ 40hz clipping was -06db
@ 100hz clipping was -06dB
@ 400hz clipping was -05dB
@ 1000hz clipping was -05dB
@ 4000hz clipping was -03dB
@ 8000hz clipping was 0dB

So, the rule of weakest links tells me that my headunit volume should be at -06dB and the c701 volume at 23 for amps' gain setting.
I used that information to continue working downstream and setting gains for amp.

Thought some of you guys might be interested to know that the h701 inputs do clip. I’ve already posted this elsewhere and was given a reason… maybe he’ll chime in here and say it again as I’m not going to quote him if he doesn’t want to be quoted.

Also, someone else said that the rear channels on the h701 are inherently noisy, so keep that in mind.

/Food for thought.
 

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Thanks for posting this data.

Now I'm really curious if the same applies to signals coming over Ai-Net or optical.

I'm running analog over Ai-Net until I can get my optical cable replaced. :blush:
 

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Why not try optical cable from P9 to H701? Guess with this way you will have better control over H701 as volume is controlled from C701. Would like to know the end results as this is what I'm planning to do. But the main setback on this will be the cable(KWE-610A is not easy to get)
 

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Discussion Starter · #7 ·
#1. I don’t have the cable to do this with.
#2. It’s not in my plans to run digital. The h701 is a temporary setup. The bit one is going back in and I don’t intend to have multiple devices just for volume control. I’d rather deal with a little bit of noise if that’s the tradeoff.
 

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Discussion Starter · #9 ·
Nope, no digital at all for me. It's just simpler for me.

Never had the p9 EQ, man. Can't say. I know others have said they like it more, but IIRC, it's limited in x-over range on the midbass channel.
 
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