New guy - questions for those running a DSP

[jfmoots]

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.

I've got an Audiocontrol LC2i and it's doing a decent job. What processor do you use?

The factory speakers in the car also sound pretty poor. Are you thinking replacing those with a better quality 6.5 and running them off the stock power will do the trick?

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[FaintReality]

I've got an Audiocontrol LC2i and it's doing a decent job. What processor do you use?

The factory speakers in the car also sound pretty poor. Are you thinking replacing those with a better quality 6.5 and running them off the stock power will do the trick?

I have a set of Hertz components, mini dsp 6x8 processor, RE audio amps and a 12" stereo integrity v3 sub. This is my commuter car so it's going to be a budget system, but should sound pretty good.

Tonight I'll try and take door panel off to hook up to speaker wires for a power measurement and see at what level the stock HU clips. For shits and giggles, I may hook up front components to the stock HU to see how they sound for those on a budget, but they will definitely be getting amplified for my final setup.

In the rear, I am still undecided but at the moment I plan to disconnect and run no rear fill. If I do, they will be attenuated a good 6-9db's lower than the front stage.

 

[jfmoots]

I have a set of Hertz components, mini dsp 6x8 processor, RE audio amps and a 12" stereo integrity v3 sub. This is my commuter car so it's going to be a budget system, but should sound pretty good.

Tonight I'll try and take door panel off to hook up to speaker wires for a power measurement and see at what level the stock HU clips. For shits and giggles, I may hook up front components to the stock HU to see how they sound for those on a budget, but they will definitely be getting amplified for my final setup.

In the rear, I am still undecided but at the moment I plan to disconnect and run no rear fill. If I do, they will be attenuated a good 6-9db's lower than the front stage.

I'd love to hear how you think they sound off the stock power.

This is my son's car and he's pestering me about upgrading the speakers. I don't want him to just throw away money if it's not going to make an improvement.

I did this back in the day when head units were way more simple...

 

[josby]

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.

Nice work! Especially for someone just learning REW.

I too got a very different curve at very low volume, which I also attributed to it being below the accuracy range of my measurement instrument. I just dropped the data I gathered for those.

One thing I find interesting is that you, measuring speaker output, got the exact same 3dB difference in relative bass volume between volume 15 and volume 35 that I got measuring the electric output at the speaker outputs. I mean, it's logical that 3dB difference in the signal would result in 3dB difference in the sound output, but still kind of cool that it matched up so precisely.

Cool that the headunit exhibits the same behavior with the bass as the Touring one does. Not really surprising that Honda would do the same thing in both, but still, I have been very curious to know for sure if it did.

Did you consider doing electrical measurements instead of sound level measurements? Since no speaker is perfect, especially OEM Honda ones, and also the fact that the car's interior affects the sound, electrical measurements would give a truer picture of what signal will be going into your DSP. Although I realize your goal was to check for volume-dependent changes to the curve, not to build a map for offsetting the factory EQ. It'd be interesting to see the result with "DSP flat", though, since your sound measurement didn't show nearly as much difference as I'd expect. Touring doesn't have that setting.

 

[FaintReality]

So I decided to take some more measurements this evening, this time with mic in drivers seat at approx. ear/head position, but with me outside of car. Volume was at 35 playing the same pink PN wave at -24 dBFS.

Green line is with the Factory EQ off (hidden feature) and red is with factory EQ on and all settings set to middle (fader/bass/mids/treble).

As you can see with the mic being in proper seating position, there is a big difference from previous measurements, but those were intended for comparison sake only. This graph is a better representation of what we actually hear from the drivers seat, but still not perfect for obvious reasons.

As you can see with the Factory EQ on, there is a 16db drop at 200hz, which is drastic and makes more sense now.

 

[FaintReality]

I'd love to hear how you think they sound off the stock power.

This is my son's car and he's pestering me about upgrading the speakers. I don't want him to just throw away money if it's not going to make an improvement.

I did this back in the day when head units were way more simple...

I didn't get a chance today since it's been so hot and got busy this evening, but plan to get started on it hopefully tomorrow. Before swapping I want to test how much power the stock HU is putting out as well as at what volume the signal clips, but should be able to get them in this weekend at the latest.

I'll post my opinion here once installed. With no tuning, I don't expect anything great, but you could be surprised. These results would also vary on speaker type chosen, so I would take it with a grain of salt unless purchasing the exact same speakers.
I feel the stock speakers with a DSP would be most beneficial for those on a budget. Something like the JL Audio fix dsp units.

 

[FaintReality]

Nice work! Especially for someone just learning REW.

I too got a very different curve at very low volume, which I also attributed to it being below the accuracy range of my measurement instrument. I just dropped the data I gathered for those.

One thing I find interesting is that you, measuring speaker output, got the exact same 3dB difference in relative bass volume between volume 15 and volume 35 that I got measuring the electric output at the speaker outputs. I mean, it's logical that 3dB difference in the signal would result in 3dB difference in the sound output, but still kind of cool that it matched up so precisely.

Cool that the headunit exhibits the same behavior with the bass as the Touring one does. Not really surprising that Honda would do the same thing in both, but still, I have been very curious to know for sure if it did.

Did you consider doing electrical measurements instead of sound level measurements? Since no speaker is perfect, especially OEM Honda ones, and also the fact that the car's interior affects the sound, electrical measurements would give a truer picture of what signal will be going into your DSP. Although I realize your goal was to check for volume-dependent changes to the curve, not to build a map for offsetting the factory EQ. It'd be interesting to see the result with "DSP flat", though, since your sound measurement didn't show nearly as much difference as I'd expect. Touring doesn't have that setting.

Honestly, I am just playing with the program to get a feel for it so I know how to use it once I have my dsp installed.

I did just realize I have the proper cable setup as my SMD distortion detector came with a RCA to + / - leads. Did you just creat a feedback loop connecting to the mic input?

So disconnect all speakers, play wave file off USB and run RTA measurement in REW with test leads hooked directly to speaker wire harness? I'll have to double check your thread again for details.

 

[josby]

So disconnect all speakers, play wave file off USB and run RTA measurement in REW with test leads hooked directly to speaker wire harness? I'll have to double check your thread again for details.

Exactly. I didn't even disconnect all the speakers - just the one I was measuring on. Although since the mid and tweeter are both on the same wire in the EX trim, I think you would want to disconnect those two. Not sure if the load of the tweeter still being connected would influence the measurement.

And be sure to start off with the low dBFS WAV files and go up until you see clipping in REW.

Very curious to see what wattage numbers you find for the headunit too. I've always assumed Honda's numbers are peak, not RMS, and probably a little exaggerated, but we'll see.

 

[jfmoots]

Just to make sure I'm not missing something...

When you use a DSP, ex. JL Fix 86, you're then adding a 4 channel amp and running your own speaker wires to the factory locations?

 

[FaintReality]

Just to make sure I'm not missing something...

When you use a DSP, ex. JL Fix 86, you're then adding a 4 channel amp and running your own speaker wires to the factory locations?

Yes! With my setup, since using the OEM HU, I will route the high level outputs of the HU (speaker wires) to the high level inputs on my dsp. From there, the RCA outputs of the dsp will feed the amps, and then you have the speaker wires going from amps directly to the speakers.

 

[jfmoots]

Yes! With my setup, since using the OEM HU, I will route the high level outputs of the HU (speaker wires) to the high level inputs on my dsp. From there, the RCA outputs of the dsp will feed the amps, and then you have the speaker wires going from amps directly to the speakers.

I'm thinking I'd make a harness with 9-wire to interrupt the factory route from the output of the headunit, sending the hi level output back to the DSP, then bring the output of the 4 channel amp back from the amp to the other side of the interrupted factory path. that way, I could just put an 8 pin Male and Female connector on the factory wires behind the radio and easy return it to a non-amped stock format with no fighting to get wires in to doors.

You think that would work? I'm assuming there's no amp somewhere after the radio in the EX.

 

[FaintReality]

Alright, so today I measured at what volume the HU clips using my SMD distortion detector. Per the instructions, I disconnected all speakers and hooked up the detector to the drivers side mid speaker wire using the supplied cable. Using a 0db test tone, I played both a 40hz & 1khz test tone, turning up the volume till the detectors distortion light flashed. I then turned volume back down till no distortion light was on.

At 40hz, the highest volume before clipping is 37. At 1khz, the highest volume before clipping is 21. Being that music is dynamic and will fluctuate at all frequency levels, per the instructions, I averaged the two for a figure of 29 which is the highest volume before clipping.

*Cliff notes - if you have an EX sedan, keep volume to 29 or below to ensure no clipping. This is with all settings set to middle (fader / bass / mids / tweeters).

 

[FaintReality]

I also took some more frequency measurements. Since all speakers were disconnected, I just hooked up the laptop using REW to the drivers side wiring that would plug into the mid as it's a full range signal.

The difference shows you what EQ settings Honda has applied to their factory default EQ for the front speakers (this is voltage so this is a pure clean signal with no noise, reflections, cabin gain, etc).

In the attached graph, red is with the factory DSP on and green is with the factory DSP off.

 

[FaintReality]

I'm thinking I'd make a harness with 9-wire to interrupt the factory route from the output of the headunit, sending the hi level output back to the DSP, then bring the output of the 4 channel amp back from the amp to the other side of the interrupted factory path. that way, I could just put an 8 pin Male and Female connector on the factory wires behind the radio and easy return it to a non-amped stock format with no fighting to get wires in to doors.

You think that would work? I'm assuming there's no amp somewhere after the radio in the EX.

Pretty sure there is no amp, I forgot to check. I'll check passenger side kick panel this evening if I don't forget again. Your plan would work great... Only thing I would keep an eye on is the amount of power to the speakers via the stock speaker wiring as its only like 22ga.

 

[jfmoots]

I also took some more frequency measurements. Since all speakers were disconnected, I just hooked up the laptop using REW to the drivers side wiring that would plug into the mid as it's a full range signal.

The difference shows you what EQ settings Honda has applied to their factory default EQ for the front speakers (this is voltage so this is a pure clean signal with no noise, reflections, cabin gain, etc).

In the attached graph, red is with the factory DSP on and green is with the factory DSP off.

That's horrific. I wish we could just disable it and keep it disabled.

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