Audiophiles: Touring factory EQ curve doesn't change with volume!

josby

Senior Member
Joined
Dec 11, 2015
Messages
840
Reaction score
542
Location
Central VA
Car(s)
2016 Civic Touring sedan, 2002 Viper
Country flag
IMG_20160915_2249117.png


I improved the measurements I did previously by using a voltage divider circuit to avoid clipping, and I measured the front tweeter signal this time too. Most importantly, I measured at different volume levels (15, 20, 25 and 30 @makemerush). That's because a lot of Honda vehicles have been found to have volume-dependent EQ, presumably to reduce the bass going to the speakers as you turn the volume up since they use crappy speakers that can't handle it.

Raw results, measured at 1/48th octave resolution then smoothed to 1/6th:

(note that these are line VOLTAGE measurements, not speaker VOLUME measurements)
response-1.png




I added the sub, mid, and tweeter curves together using REW's A+B trace math to make it easier to compare the shape of the curve at each volume level:
response-2.png


So, no wonky EQ that varies with the volume setting like many Hondas have! This is great because it means if you use one of the many OEM integration DSP products that measure and correct the output of factory headunits (e.g. JBL CleanSweep), you won't have the problem of the curve changing as you increase or decrease the headunit volume. Flat output is possible at all volume levels!

Note: no conclusions should be drawn from this for the lower trim stereos (the ones without a factory sub)! It's possible (and in my opinion likely) that they do not work the same way.





Advertisement

 
Last edited:
OP

josby

Senior Member
Joined
Dec 11, 2015
Messages
840
Reaction score
542
Location
Central VA
Car(s)
2016 Civic Touring sedan, 2002 Viper
Country flag
  • Thread starter
  • Thread Starter
  • #2
I also checked the center channel (purple) out of curiosity just to see how much bass and treble they allow to go to that little speaker:

center.png
 
Last edited:

kvnhmmd

Senior Member
Joined
Oct 2, 2016
Messages
54
Reaction score
22
Location
Washington
Car(s)
2017 Civic Sedan Touring
Country flag
Thanks for sharing your findings. I don't own a civic (yet) but it will be my next car in the coming months.

What's your opinion on the quality of the Civic Touring's speakers? What upgrades are you planning? Interested in following your modifications.
 
OP

josby

Senior Member
Joined
Dec 11, 2015
Messages
840
Reaction score
542
Location
Central VA
Car(s)
2016 Civic Touring sedan, 2002 Viper
Country flag
  • Thread starter
  • Thread Starter
  • #4
Overall I think the system isn't terrible. I've had cars that made me rush to upgrade, but this isn't one.

The biggest deficiency is the subwoofer. There are actually some songs that seem just right for it and it's not too bad, but other songs almost totally lack bass. Plugging an aftermarket self-amplified sub with built-in LOC to the factory sub connector would be an easy fix for this for anyone with a Touring. You can even use this speaker adapter, and there's an easy hole in the firewall and a terminal on the battery + for adding power, so no cutting wires or drilling holes needed.

The other thing I notice is some high frequencies playing through the tweeter seem to distort. You get a harsh sound that goes away if you turn the volume down (I don't listen at super high volumes, either). I don't think it's due to a lack of amp power - I think it's just a not-great tweeter.

With the DTS Neural setting OFF, the center channel speaker actually does a pretty good job of centering the sound stage and raising it up. If you unplug the center speaker, the sound falls down and over onto the door closest to you. The biggest problem there is the center doesn't have a tweeter, so centered midrange sounds appear to come from the center of the car, but centered highs all come from the door closest to you. Somehow this effect is even worse with DTS Neural turned on.

For comparison, my other car has a Alpine HD149BT deck, JBL MS-8 DSP, JL Audio HD900/5 amp (100Wx4 + 500Wx1), JBL 670GTi 6.5" mids and 1" tweeters, and JL 10W3v3 10" sub in a sealed box in the trunk. When I listen to the same songs on my iPod in that car, it definitely sounds much better. I hear more detail and the sound is somehow more "pure" sounding, if that makes sense. When I get back in my Civic, the sound seems kind of dull and lifeless. Voices don't sound as real.

I'm installing another of those JBL MS-8 DSP's in my Civic now. I plan to do that, then decide the next mod needed based on the results from that. I think the next thing will almost definitely be adding a better sub, then upgrading the center channel, and then who knows after that.
 
Last edited:
OP

josby

Senior Member
Joined
Dec 11, 2015
Messages
840
Reaction score
542
Location
Central VA
Car(s)
2016 Civic Touring sedan, 2002 Viper
Country flag
  • Thread starter
  • Thread Starter
  • #5
flat.png


I finally got my MS8 temporarily connected tonight and ran its automatic input calibration to see how well it would be able to flatten the signal coming from the factory amp. All tone/sub/balance controls were set to centered on the headunit. The results are shown above, along with the curve that comes out of the factory amp for comparison. I'm pleased with the result. The dip around 65 Hz is kind of odd, but it's only a few dB. The slight rolloff below 40 Hz is strange too. Initially I was thinking it was due the MS8's 20 Hz subsonic filter, but it wouldn't start going back up below 27 Hz if that was the cause. Anyway, it's definitely close enough for me.
 
OP

josby

Senior Member
Joined
Dec 11, 2015
Messages
840
Reaction score
542
Location
Central VA
Car(s)
2016 Civic Touring sedan, 2002 Viper
Country flag
  • Thread starter
  • Thread Starter
  • #6
bass-adjustment.png

mid-adjustment.png

treble-adjustment.png


Even though I don't plan on using the headunit's tone controls since the MS8 has its own, and a 30-band EQ as well, I was just curious to see what the effects of the headunit controls are. Above are the results from turning the bass slider all the way up and down, the mid slider, and the treble slider.

One odd thing is that increasing any of those controls to the max doesn't seem to have as large an effect as turning them down does (especially the mid control), and I have no idea why that would be. The other odd thing is the weird stuff that the bass control does - turning the bass up to the max bumps the frequencies from 70 to 300 Hz, but slightly decreases the bass below 70 Hz, and turning the bass all the way down does the inverse. Weird.
 
OP

josby

Senior Member
Joined
Dec 11, 2015
Messages
840
Reaction score
542
Location
Central VA
Car(s)
2016 Civic Touring sedan, 2002 Viper
Country flag
  • Thread starter
  • Thread Starter
  • #8
Conceptually, you need a way to convert the analog signal that's normally sent to the speakers into a digital form that software can read.

This post and the post it links to should help. The hardest part is making a cable and voltage divider to get the sound output from your speaker wires into the computer's sound card. If you want to tackle it and have questions, let me know.

Or, since you're in Maryland, you're welcome to drive down to Richmond and I'll do it. I am curious to see how different the sub-less/amp-less headunit output is.
 
OP

josby

Senior Member
Joined
Dec 11, 2015
Messages
840
Reaction score
542
Location
Central VA
Car(s)
2016 Civic Touring sedan, 2002 Viper
Country flag
  • Thread starter
  • Thread Starter
  • #9
Sorry, bad news - I didn't look closely enough at this. The curves in the first post looked so close that I thought they were the same, but then when I was installing my DSP, I noticed the bass seemed to vary depending on where I had my headunit volume set relative to my DSP's volume setting, so I looked at this again and I was wrong. The curve does change a little depending on headunit volume number.

The differences are small enough that they're hard to see unless you shift each trace so that the frequencies above bass frequencies overlap since those curves are constant regardless of volume level. So, what I found is:

vol-40-29.png
Not too bad so far - going from volume 40 down to volume 29, the bass is virtually identical relative to the higher frequencies at all those volume levels.


vol-29-20.png
Going from volume 29 down to 20, it starts to pick up a little. At volume 20, the bass is roughly 1 dB louder relative to the rest of the music than it is at volume 29.


vol-20-15.png
From volume 20 down to 15, the jumps get bigger. Bass at volume 15 is 2 dB higher relative to the rest than it was at volume 20, and 3 dB higher than it was at volume 40.


All this isn't necessarily a bad thing. People generally like a little bass boost when they're listening to music at a quiet volume.

The takeaway from this, I think, is that when you're adding aftermarket amps and such and using the factory headunit as your source, you want to set the gains on your amps/DSP/etc so that you're using the whole volume range of the headunit.

If instead you set your gains such that, say, level 10 is pretty quiet and only 25 is as loud as you can stand it, you'll get noticeable bass jumps each time you change the volume a little, especially in the 10-20 range.
 
Last edited:

zroger73

Senior Member
Joined
Apr 15, 2017
Messages
2,457
Reaction score
4,489
Location
United States
Car(s)
2019 MX-5 Miata GT-S, 2020 CX-5 Signature
Country flag
@josby, thank you for the information in this thread. As an engineer (though not in the discipline of car audio), I geek out over objective data like this.
 
Last edited:
OP

josby

Senior Member
Joined
Dec 11, 2015
Messages
840
Reaction score
542
Location
Central VA
Car(s)
2016 Civic Touring sedan, 2002 Viper
Country flag
  • Thread starter
  • Thread Starter
  • #11

cestjoel

Senior Member
Joined
Jul 2, 2017
Messages
319
Reaction score
143
Location
SoCal
Car(s)
2017 Civic Hatchback Sport CVT
Country flag
Sorry, bad news - I didn't look closely enough at this. The curves in the first post looked so close that I thought they were the same, but then when I was installing my DSP, I noticed the bass seemed to vary depending on where I had my headunit volume set relative to my DSP's volume setting, so I looked at this again and I was wrong. The curve does change a little depending on headunit volume number.

The differences are small enough that they're hard to see unless you shift each trace so that the frequencies above bass frequencies overlap since those curves are constant regardless of volume level. So, what I found is:

vol-40-29.png
Not too bad so far - going from volume 40 down to volume 29, the bass is virtually identical relative to the higher frequencies at all those volume levels.


vol-29-20.png
Going from volume 29 down to 20, it starts to pick up a little. At volume 20, the bass is roughly 1 dB louder relative to the rest of the music than it is at volume 29.


vol-20-15.png
From volume 20 down to 15, the jumps get bigger. Bass at volume 15 is 2 dB higher relative to the rest than it was at volume 20, and 3 dB higher than it was at volume 40.


All this isn't necessarily a bad thing. People generally like a little bass boost when they're listening to music at a quiet volume.

The takeaway from this, I think, is that when you're adding aftermarket amps and such and using the factory headunit as your source, you want to set the gains on your amps/DSP/etc so that you're using the whole volume range of the headunit.

If instead you set your gains such that, say, level 10 is pretty quiet and only 25 is as loud as you can stand it, you'll get noticeable bass jumps each time you change the volume a little, especially in the 10-20 range.
So, where do I set the volume on my head unit (LX/Sport Models) for the JL Audio fix 86? It says to set it at 3/4 of the full volume. But, at that level, the bass is already decreasing big time. What effect will it have when I put the volume in the HU lower? Man, I wish you were in CA so I can take my car to you. Lol
 

integra15

Senior Member
Joined
Jun 22, 2017
Messages
555
Reaction score
238
Location
Ann Arbor
Car(s)
2017 Civic SI
Country flag
This is great info. Overall I think the system is decent except the sub, like you said. It adds so little to the overall experience I wonder why they bothered at all. I have one of these on order now and with the addition I think I am going to be satisfied

https://www1.crutchfield.com/p_777B8PTD/Sound-Ordnance-B-8PTD.html

Not the best brand but it's cheap. Going to mount it to the rear seat back along with an audiocontrol LC2i
 
OP

josby

Senior Member
Joined
Dec 11, 2015
Messages
840
Reaction score
542
Location
Central VA
Car(s)
2016 Civic Touring sedan, 2002 Viper
Country flag
  • Thread starter
  • Thread Starter
  • #14
So, where do I set the volume on my head unit (LX/Sport Models) for the JL Audio fix 86? It says to set it at 3/4 of the full volume. But, at that level, the bass is already decreasing big time. What effect will it have when I put the volume in the HU lower? Man, I wish you were in CA so I can take my car to you. Lol
Well, it's possible the LX/Sport radio may behave differently than this - I haven't measured one and it's definitely a different unit than the Touring. So take this with a grain of salt. But if I had to bet, I'd guess it will behave the same.

Don't think of it as the bass decreasing at higher volumes - think of it as bass increasing at lower volumes.

I would calibrate it around volume 30-35. Better to go too high than too low. You could calibrate it at 40, but the signal level of the calibration track is probably at the maximum, while the level of most music won't be, so calibrating at 40 would probably waste some headroom. Calibrating at anywhere from 29-40 will give the same sound profile, just with a lower max volume if calibrated at 40, and the possibility of distortion at volume 40 if calibrated at 29.

Once you have that calibrated, the effect will be that at volumes 29-40, your amps will be getting exactly the signal that's in your music. Below volume 29, the bass level will be slightly higher relative to the rest of the music. Down to volume 20, the increase is pretty slight, though. Below volume 20, the increases get bigger. At that point your music should be pretty quiet. At that quiet level, the extra bass will make things sound better.

So basically you want your amp gains set such that your normal driving-alone-and-jamming-to-a-song-you-love volume position is in the 30's, and your it's-dark-and-I'm-lost-so-I-turn-the-music-down volume is somewhere in the teens. :D
 

cestjoel

Senior Member
Joined
Jul 2, 2017
Messages
319
Reaction score
143
Location
SoCal
Car(s)
2017 Civic Hatchback Sport CVT
Country flag
Well, it's possible the LX/Sport radio may behave differently than this - I haven't measured one and it's definitely a different unit than the Touring. So take this with a grain of salt. But if I had to bet, I'd guess it will behave the same.

Don't think of it as the bass decreasing at higher volumes - think of it as bass increasing at lower volumes.

I would calibrate it around volume 30-35. Better to go too high than too low. You could calibrate it at 40, but the signal level of the calibration track is probably at the maximum, while the level of most music won't be, so calibrating at 40 would probably waste some headroom. Calibrating at anywhere from 29-40 will give the same sound profile, just with a lower max volume if calibrated at 40, and the possibility of distortion at volume 40 if calibrated at 29.

Once you have that calibrated, the effect will be that at volumes 29-40, your amps will be getting exactly the signal that's in your music. Below volume 29, the bass level will be slightly higher relative to the rest of the music. Down to volume 20, the increase is pretty slight, though. Below volume 20, the increases get bigger. At that point your music should be pretty quiet. At that quiet level, the extra bass will make things sound better.

So basically you want your amp gains set such that your normal driving-alone-and-jamming-to-a-song-you-love volume position is in the 30's, and your it's-dark-and-I'm-lost-so-I-turn-the-music-down volume is somewhere in the teens. :D
I re-calibrated again at volume 30 and it sounds a lot better — the signal isn't as hot as it used to be. However, I still need to use the JL Tun 2.0 software to EQ the signal a bit.

This is why I love aftermarket stereos. You can do all the tuning with the head unit instead of going back n forth with the amps and the lap top. Lol
 

Advertisement






Advertisement
Top