I have the 4-door accord EX with the stock head unit with XM (no nav). Has anyone figured out what the approximate unclipped volume of that head unit is? Searched and found out how to do it, but I don't have an oscilloscope so I can't do it myself.

Thanks.

Answer: Vol. level 24 @ 40Hz and level 27 @ 1 KHz - I went with 24 for my purposes... Used a DD1 to figure it out btw.

 

you could get a dd-1. they are a lot cheaper than scopes. I would imagine that it is different from car to car. also if you have a stock system the factory speakers will probably distort before the HU clips.

 

clipping volume depends on the record level of the source. each CD is recorded different. modern music may even include clipping in the recording.

only a true 0dB test tone would give an indication and it would be relative at best.

it will also vary with EQ settings.

why do you want to know?

 

example of what i'm talking about with recorded levels here:
What does a bass boost do? - Page 3

 

I installed an alpine imprint and as part of it's calibration process it instructs me to set the volume to the max unclipped setting on the HU for some test tone sweeps. Don't know for sure what that value is so I'm hoping a couple people have already measured that when doing their own install so I can pick a safe max value.

Diagram of my install as reference:

 

nice gear, but the "max unclipped volume" depends on the source used. so it's a relative metric.

you want to achieve two things:
1. low distortion at high volume levels
2. adequate volume adjustment range

choose too high of a volume and you amplify distortion
choose too low of a volume and you don't get enough positions (quickly goes from quiet to loud).

anything above 50% will have audible distortion. those MLK speakers are deadly accurate and will reproduce any deficiencies in the system.

i would shoot for about 40% of max volume as your calibration level (so around VOL 15). that way the head unit amplifier distortion is kept to a minimum and you have a decent volume range. note that you will want to avoid going over this "max" volume or you can start to clip the system.

you also still need to set your amp gains according to the output of the Imprint system.

 

The source will be a CD provided by Alpine with specifically configured sweep test tones that aren't set to clip on their own. Yes, I fully understand some music is poorly produced or will clip like crazy... but that's irrelevant to my current situation.

The imprint is a processor that takes the signal from the head unit and applies time alignment and EQ. It first needs to be configured at the max HU volume so it can properly calibrate itself and produce the cleanest signal downstream to my amps (up to 4v). If I were to set the volume at 15 or so, it would be reading a much weaker clean signal than is actually possible (probably only .5v instead of closer to 2v or whatever it's supposed to put out). Letting the imprint think my head unit could only produce a .5v clean signal would actually introduce a whole mess of unnecessary noise into the system.

If you don't know or have never measured what the max unclipped volume setting is on a 7th gen Honda is, that's OK, but I don't need to be talked out of what I'm asking for; rest assured, there's a good and valid reason. Thanks for your thorough responses though but I'm just looking for a simple answer if anyone has measured this on their stock head unit before.

If I break down and take it to someone who has an oscilloscope or buy a DD-1, I'll certainly post my findings in case anyone else runs across this thread looking for the same answer. Until then, the question remains open! Cheers.

 

I think what KHA is trying to say is that there are far too many variables for anyone to be able to tell you a number. I dont think he is trying to talk you out of anything.

 

Understood... when I had an installer check on another car a while back, he verified the max clip volume of that head unit at roughly 35 out of 40 and that was very consistent for that make and model's stock head unit he had tested in the past. They were always within +/- 1 or 2 points of that if all Tone settings were flat. Just trying to get that info for the Accord. Do I need to keep it around 30 for the calibration or can I get closer to 35/36 and still be OK? 15 is definitely way too low.

I'm not going to listen to music at 35 or 36, it's just a calibration step to setup the imprint properly. For example, this radio is built to specs so it won't start clipping a 1kHz 0db tone until it gets to about XX on the volume ****. Just trying to see if anyone knows what that approx value is. He's right on all other points about music and it's production however, I'm not saying he isn't.

 

I would test it for you on my car but I dont have a head unit. it quit working so I just roll with th xm reciever and my phone. if I come across one and have a chance to check I will but dont know when/if that will come up.