New guy - questions for those running a DSP

[FaintReality]

I just picked up a 2017 Civic EX this past weekend as a commuter car and am looking to get started on my install. With this in mind, I have been reading through this section the last few days and have some DSP related questions.

- Have we still not figured out a way to turn off the preset EQ and make it stick once car is restarted? I ran by local dealer yesterday to so if they could flash it to default to off upon startup, but it was a no go.

- I can work with internal EQ since my DSP has full control of both inputs & outputs, so I plan to tap into the front pair as the rear are heavily EQ'd vs the front based on my testing. With this in mind, does anyone know if the frequency response is linear with the volume or does the internal EQ change the curve based on volume adjustments? I could not find much info on the EX as most of you guys discuss the touring model with external amp.

The two above questions are about it. I may try to get out there with the mic today and take some measurements to see if the EQ is volume dependant, requiring me to use my DSP's master volume which I'm hoping is not the car.

Thanks in advance,
Dave

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[leaat23]

I'm sure there is some kind of 'auto loudness' going on with the stock unit, the more you turn it up the less bass you seem to get. I had a huge system in my old Impreza and I am looking for a way to keep the stock HU in my new Civic and use my old amplifiers as they are top notch B2 and DSL with CDT 6.5" reference fronts and focal rears, my sub is a Sundown Audio Z12 V2 in a 2.5cuft ported box and I'm running 3kw RMS into that, I'm thinking of buying a B2 DSP but I'm aware my car has the amped system with 11 speakers, so may have to break into the low level outputs that are balanced instead of the usual unbalanced according to wiring diagrams found on these forums. It's going to take some time but I am determined to get this audio system sounding as it should.

 

[FaintReality]

DSL or DLS? I use to run DLS amps and CDT comps back in like 03-04, good stuff. I still have a set of Zapco amps, Seas mids & Hiquphon tweets from my last active install back in 05, but decided to build a budget system for the commuter car since I already have everything purchased.

Seems like the oem setup with the amp is a mess but those of us with the LX or EX may have it easier it seems. Hopefully someone with an EX has plotted the frequency response with various volumes and will chime in...

 

[leaat23]

Sorry

DSL or DLS? I use to run DLS amps and CDT comps back in like 03-04, good stuff. I still have a set of Zapco amps, Seas mids & Hiquphon tweets from my last active install back in 05, but decided to build a budget system for the commuter car since I already have everything purchased.

Seems like the oem setup with the amp is a mess but those of us with the LX or EX have it easier it seems. Hopefully someone with an EX has plotted the frequency response with various volumes and will chime in...

DLS, my dislecsia kicking in.

 

[jfmoots]

It's a nasty little system. Just using my ear, I can tell it positively drops bass out as the volume goes up. I've also tapped in to the front speaker output but the signal is rough...

I'm only running a sub so I can only speak to the bass modifications the DSP makes. I ran it through an LC2i to try to clean it up, but it's only a marginal improvement.

There's a setting in the developer menu that allows you to set the DSP to flat, but it doesn't stick with a power cycle of the car.

I also spoke with PAC audio yesterday. They have zero plans to make an adapter that provides a flat line out.

 

[FaintReality]

It's a nasty little system. Just using my ear, I can tell it positively drops bass out as the volume goes up. I've also tapped in to the front speaker output but the signal is rough...

I'm only running a sub so I can only speak to the bass modifications the DSP makes. I ran it through an LC2i to try to clean it up, but it's only a marginal improvement.

There's a setting in the developer menu that allows you to set the DSP to flat, but it doesn't stick with a power cycle of the car.

I also spoke with PAC audio yesterday. They have zero plans to make an adapter that provides a flat line out.

And you have the non amplified system like the EX? If so, that's definitely not what I was hoping to hear.

I was going to run some frequency test yesterday with my mic setup & laptop but we do not have an aux input. I ordered a male to male usb cable to try and connect laptop, but no clue if car will read it or not. Cable will be here tomorrow.

 

[jfmoots]

And you have the non amplified system like the EX? If so, that's definitely not what I was hoping to hear.

I was going to run some frequency test yesterday with my mic setup & laptop but we do not have an aux input. I ordered a male to male usb cable to try and connect laptop, but no clue if car will read it or not. Cable will be here tomorrow.

I have the EX. It's an amplified system.

 

[FaintReality]

I have the EX. It's an amplified system.

Do we have external amp or just internal HU amp?

 

[jfmoots]

Do we have external amp or just internal HU amp?

To the best of my knowledge, it's an external amp. The head unit had a fiber optic output on it that gives back to the amp. It's a constant volume though so you can't just convert it an input it in to an amp. You need the CANBUS (or similar info) to control the volume.

 

[josby]

To the best of my knowledge, it's an external amp.

I lose track of what each trim has in the coupe and hatch forms, but the simplest rule to follow is: Civic with no center channel speaker = no external amp.

 

[FaintReality]

I have sedan. From what I read, it has no external amp. I did read they are in passenger side kick panel so I will pull panel to verify.

Now I just need to figure out how to get the USB ports to read my flash drive so I can play a WAV file and take some measurements. I converted to MP3 as well with no luck. Any insight?

 

[FaintReality]

Alright, for those of you with the EX models, like the touring, as volume is turned up, the lower end is attenuated. At 75hz, there is a 3db drop (volume 15 vs 35) that slowly evens out to around 250hz, then is within .5db all the way out to 20khz.

In the 1st graph below, I played the pink PN tone, turned volume to 5, took RTA measurement and saved. Then the same at volume 10, 15, 20, 25, 30 and lastly volume 35.

When looking at graph, all look linear and have the same spl gap across the full range with the exception of volume 5 which I think is due to the inaccuracy as it's too close to the noise floor level.

Upon further inspection when overlapping graphs, it looks like the built in dsp does indeed cut the lower frequencies when volume is raised.

In the 2nd graph below, I overlapped volume 15 (red) and volume 35 (blue), and you can see there is a ~3db cut centered at 75hz.


**disclaimer - all measurements were taken from passenger seat with the mic held in place between top of seat and bottom of head rest. Fader and bass/mid/treble were set to middle and SVC is set to off. For those of you trying to tune, do not use these frequency responses as they are not accurate and were only used for comparisons against various volume levels with all else remaining the same.

 

[jfmoots]

Alright, for those of you with the EX models, like the touring, as volume is turned up, the lower end is attenuated. At 75hz, there is a 3db drop (volume 15 vs 35) that slowly evens out to around 250hz, then is within .5db all the way out to 20khz.

In the 1st graph below, I played the pink PN tone, turned volume to 5, took RTA measurement and saved. Then the same at volume 10, 15, 20, 25, 30 and lastly volume 35.

When looking at graph, all look linear and have the same spl gap across the full range with the exception of volume 5 which I think is due to the inaccuracy as it's too close to the noise floor level.

Upon further inspection when overlapping graphs, it looks like the built in dsp does indeed cut the lower frequencies when volume is raised.

In the 2nd graph below, I overlapped volume 15 (red) and volume 35 (blue), and you can see there is a ~3db cut centered at 75hz.


**disclaimer - all measurements were taken from passenger seat with the mic held in place between top of seat and bottom of head rest. Fader and bass/mid/treble were set to middle and SVC is set to off. For those of you trying to tune, do not use these frequency responses as they are not accurate and were only used for comparisons against various volume levels with all else remaining the same.

Nice work, man! That's very detailed!

What's your plan to fix it?

 

[FaintReality]

In this graph, you can see the difference between the normal factory EQ with all settings in the middle (fader/bass/mids/treble) vs the EQ & loudness turned off in the hidden menu.

The biggest difference is at ~8khz and is a little over 1db difference. This is with the volume set to 35 and is top frequency response in attacehd graph. Purple is with DSP on and orange is with DSP off.

Bottom frequency response is at volume 15. Blue is with DSP off and red is on.

On paper, not a huge difference. Nothing to worry about if you have a decent processor. To the ear, the rear speakers are noticeably attenuated vs with the dsp off, and there is definitely some time alignment going on with the stock EQ on, which is the biggest change most people hear when comparing.

 

[FaintReality]

Nice work, man! That's very detailed!

What's your plan to fix it?

With my processor, I'm not worried about the frequency response or the difference between factory EQ on vs off (hidden menu). As for the 3db attenuation between volume 15 & 35 at 75hz, I think I'll be fine since my normal listening levels are toward the middle range and lower once amplified. With that in mind, the difference w ont be as great and I can always adjust the low end with the dsp if too much or too little.

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