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Discussion Starter #1
Guys,

I am by all means an amateur who is learning how to get the most out of my system. I run an MS-8 which has the ability to auto set levels, and subsequently auto-eq my system. However its ability to do so on the EQ side is limited to 9dB. Thus I am wondering if using the sub's power amp to "pre-eq" the sub to flat, is a good idea, which then gives the MS-8 more room with which to work.

In particular, the MS-8 sets level matches the sub in a higher frequency range where it is not as strong, to it then has to EQ the lower range by a lot to flatten it out.

My sub is the ID10 D4 v.3 and here is it's LEAP profile

The amp is the Alpine MRD-M300 which allows for a parametric EQ with:
  1. Center frequency selectable by 1/3 octave
  2. Q of 1 or 3
  3. +/- 2dB up to total of 10dB
So my thought was either boost the high end, or cut the lowend to make the sub as flat as possible before the MS-8 tries to fix it. This might allow for better level matching across my system

However, I know this LEAP won't reflect any cabin gain (BMW 3-series e90) and I don't know much about that, nor the particular enclosure characteristics (I am trying to get the exact volume from VP Electricity). Thus, I don't know if I am even starting on the right track.
 

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you really need to RTA the response once it is in car. free air recordings of FR are useless once it is in a box and that box is in a car.

as for the idea, no its not a bad idea to smooth out small FR issues with a PEQ.
 

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Discussion Starter #3
you really need to RTA the response once it is in car. free air recordings of FR are useless once it is in a box and that box is in a car.

as for the idea, no its not a bad idea to smooth out small FR issues with a PEQ.
Thank you for the response.

The LEAP profile posted above includes a FR curve that is specific to mounting in a sealed enclosure. So that's one order closer to the end result, of course no account for the car it's in (pending some answers regarding cabin gain in my car from a more familiar expert).

I WILL RTA the car, but I thought in this case I should put the chicken before the egg, kind of a rough guestimate.

I guess I could RTA the un-eq'd, pre MS-8 response, THEN EQ,it again, add the MS-8 and get a final RTA? Is it necessary to RTA before and after since I have multiple variables (AMP EQ, MS-8 Level set, MS-8 EQ)?
 

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if you are not going to let the MS8 do an auto-tune (not a fan of auto-tune myself) then I would do your initial RTA with all EQ set flat. set your gains and your x-over points to whatever is recommended, but leave the EQ flat. once you RTA your system in the car, you will see exactly where you need to make cuts.

also, the RTA is a starting point. once you have it as flat as you can with the RTA, you may want to make slight changes to suit your ears.
 

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Nothing wrong with trying it. I'd just play some tones by ear and PEQ until it sounded flat; the same volume by ear at various Hz. That should get you close and not take that long. Since the MS8 is going to EQ it anyway seems like close would be plenty good enough.

My 880PRS has a mic too and auto thing, it shut my subs off. It shut off a pair of 15s with Fs 20 and Qts .7. They play near flat to about 30Hz in the model and in the car, so if it is anything like this Pioneer I may not make any difference. I don't use the auto thing either but guess it was fun to mess with and helpful for the TA.

I have a M301 in there right now but it kind of gives out at high output, but works well and is playing with no SS filter. Have to put the M500 back in. I use the 16 band EQ in the HU, but those amps are nice.

What is LEAP, a 10 that peaks at 18Hz in a sealed you have to be kidding me. I would fill my pants if it did that in my car, because a lot of other 10 and 12 would not and even my pair of 15s IB can hardly make much under 25Hz which is massively lower than the box speakers did. I know ID are far from junk, but that chart does not seem realistic.
 

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Discussion Starter #6
if you are not going to let the MS8 do an auto-tune (not a fan of auto-tune myself) then I would do your initial RTA with all EQ set flat. set your gains and your x-over points to whatever is recommended, but leave the EQ flat. once you RTA your system in the car, you will see exactly where you need to make cuts.

also, the RTA is a starting point. once you have it as flat as you can with the RTA, you may want to make slight changes to suit your ears.
I do plan on letting the MS-8 do its thing, however, from what I learned, once it runs out of room to do its thing @~9db, you start to get funky results. So, I am trying to make it easy on the MS-8 by eliminating the big peak (or filling the valley, whichever might be better?)

So I will take that to as advice to do a pass-through on MS-8, then RTA to adjust amp gains to match, then EQ the sub using the parametric band. only then let the MS-8 tune, then I will RTA once again to get the curve I want.

Any recommendations (theoretical) on what values you would select to flatten the posted curve? Would you cut the Low end, or boost the high end?
 

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I do plan on letting the MS-8 do its thing, however, from what I learned, once it runs out of room to do its thing @~9db, you start to get funky results. So, I am trying to make it easy on the MS-8 by eliminating the big peak (or filling the valley, whichever might be better?)

So I will take that to as advice to do a pass-through on MS-8, then RTA to adjust amp gains to match, then EQ the sub using the parametric band. only then let the MS-8 tune, then I will RTA once again to get the curve I want.

Any recommendations (theoretical) on what values you would select to flatten the posted curve? Would you cut the Low end, or boost the high end?
this was for the sealed curve right?

since you are likely gonna add a x-over around 80 hz anyway, I wouldnt do anything at the high end. maybe cut 40 hz by about 2-3 dB and 25 hz by about 4-5 dB. but honestly, until it is in the car, these are spitballs. the FR will totally change in the car.
 

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Discussion Starter #8
this was for the sealed curve right?

since you are likely gonna add a x-over around 80 hz anyway, I wouldnt do anything at the high end. maybe cut 40 hz by about 2-3 dB and 25 hz by about 4-5 dB. but honestly, until it is in the car, these are spitballs. the FR will totally change in the car.
Yes, for the sealed curve,

As far as I understand, I get a single band of fully parametric EQ, thus I get to pick the center freq, the curve width, and the gain, cut amount...can't pick multiple points.

That's where i REALLY need someone smart, to figure out what are the right variables to counteract that curve. At least if I get it close on paper, I can see how it does in the car w/ cabin gain.

Anyone know of an online tool that will parametrically EQ a given curve?
 

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Discussion Starter #9
What is LEAP, a 10 that peaks at 18Hz in a sealed you have to be kidding me. I would fill my pants if it did that in my car, because a lot of other 10 and 12 would not and even my pair of 15s IB can hardly make much under 25Hz which is massively lower than the box speakers did. I know ID are far from junk, but that chart does not seem realistic.
LEAP, AFAIK is just a program. Loudspeaker Enclosure Analysis Program.

Who knows what's happening in the car, I do know the boomy low end pressurizes my ears the same way as a compression wave does ...its NOT comfortable!
 

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Yes, for the sealed curve,

As far as I understand, I get a single band of fully parametric EQ, thus I get to pick the center freq, the curve width, and the gain, cut amount...can't pick multiple points.

That's where i REALLY need someone smart, to figure out what are the right variables to counteract that curve. At least if I get it close on paper, I can see how it does in the car w/ cabin gain.

Anyone know of an online tool that will parametrically EQ a given curve?

if you only get one, the pick somewhere in the middle and use a high Q value.

33-35 hz with a Q of 1.5-2. this will bring down a much larger effective area.
 

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I just play tones and tone sweeps, say 25-70Hz, at a moderate volume. I can tell volume differences very easily. When you know what the tone is, it is easy to cut/boost the EQ to level them out. In my car until I ran large IB it died under 40Hz and I didn't want a huge box. It gets hard to hear 20hz so not sure how significant that tone is to play, may depend on you. Since I feel it more I can tell in music with it but the tone I can't gauge the volume in comparison to higher frequency, I'd need a meter.
 
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