Malmenator

This is somewhat what I was asking about in post #290 above. There are 5 bands of adjustability for each section of Bass, Mid, and Treble, so 15 bands total. and each band appears to have the ability to change frequency and Q Value (the pic in the post). While I more or less understand the frequency adjustment part, does anyone know what Q Value is? They all seem to be set at 1.662

RhinoComp

Think of each frequency value as a point on the EQ line that it raises or lowers. It curves the base signal response up or down to the value you request, and the Q value is just how sharply you want the line to curve to the point. A Q value of .01 is very flat, and a Q value of something like 5 is a very sharp curve towards the point. Since there isn't a visualizer to the Mr12Volt parametric EQ, I wouldn't really mess around with it too much unless you're using real time analysis to correct a very sharp dip or peak in your frequency response of the whole system. The default around 1.5 is a pretty reasonable place to keep it.

Malmenator

Honestly, I would fly you over here to fine-tune my stereo setup if I could. Your responses as an unofficial tech support are amazing. Thank you for sharing your knowledge!

bokh

Have a question, not sure if it came up before: I have a Mr12Volt and after market backup camera in a manual transmission 991. I wired the backup camera to get its power from the taillight. Now I'm thinking about adding a front camera. How would it be wired? where would it get its signal from? does Mr12Volt trigger it when in 1st gear?

Thanks

Roman ACS

I've not done it but I belive you can write it to parking sensors.

renntier

Too lazy to read the full discussion right now but as someone who's worked in audio I completely agree with RhinoComp - always do subtractive EQing, that means if you want to boost one frequency, just reduce down the other ones. If you want to do a +5 on 100hz, just think of -5 as the new 0, pull down all other frequencies to -5 so the 100hz at 0 is now at a relative +5. The only downside is that you will miss out on maximum volume but trust me this really will not be a concern.

The reason for this is because you can never be sure that the system you're working with is actually smart enough to subtract the maximum boost from the overall volume. If you want to dig really deep you will also find that in rare instances, even using only negative values can cause clipping due to how filters and EQs work (depends on the EQ). If you want to dig even deeper you can look into inter sample peaks for full anxiety. It's the reason why I, additionally, put the maximum volume from 32 down to 30. Depending on how the gain staging works internally this won't prevent your speakers from slowly going bad if the signal distorts at a lower level already, but it's one more thing you can do just to be safe. I'm practically deaf when it comes to how high I turn up the volume and I still am far from the max volume, even with my subtractive setup.

I am however a bit surprised/dissatisfied with the amount of sub bass (<40hz) with the Mr12Volt but I haven't had the time to feed the sub a direct signal for comparison. So I can't yet tell whether it's Mr12Volt's fault or if the 957 Bose sub really doesn't offer much below 40hz.

heeltoejunkie

can you share which backup camera you used? I’d like to add a backup camera but haven’t seen a lot of people do it here. Thanks!

bokh

Natika. It is really great.

Gus B.

@RhinoComp and @renntier : assuming you had access to a RTA, would the "baseline" EQ settings before adjusting be all bands at -5db and then "boost" (to a maximum of 0db) whatever frequency requires adjusting? If this is the case, wouldn't the sound be radically different than the intended final outcome as one would be subtracting (every band at -5db) most of the sounds?

Forgive my ignorance, it's just that I have never heard of this way of adjusting before and it goes completely against what I've seen since the 80s when we had EQs as part of the dash on aftermarket stereos (yes, I am dating myself...).

polish

Is the main harness that comes with the Mr12Volt labeled for PCM 3 or PCM 3.1? I purchased a Mr12Volt unit (directly from their site, mistakenly) and the provided MOST harness does not fit. The packaging was labelled for a 3.1 as is the Mr12Volt itself but the main harness is labeled PCM3. I wonder if this is the cause of the issue that I'm having. I've contacted them, sent pictures of everything but haven't had any sort of a follow-up/response since their initial email asking for some further details.

Roman ACS

Feel free to call me and I'll walk you through it.

Joostem

I did the install yesterday, changed from isudar to Mr 12 volt. System works great but I have one issue.

my car has the tv tuner from factory and I was told for Mr 12 volt to work I have to just loop the MOST bus from the TV tuner. I did that only now I have no more backup camera. They assured it would work.

When I do a obd scan I get backup camera to PCM open circuit. Any ideas?

As far as I know backup camera goes from camera to backup camera controller to tv tuner to PCM. According to the wiring schematic not via the MOST.

Kelsh

Roman,
Any chance you also repair PCM 3.1 reboot issues?

Roman ACS

I have never seen this option in person. Unfortunately I don't have any experience with this.

Roman ACS

No, that is usually a failing hard drive.