Tuning with the miniDSP C-DSP 8x12 DL and REW

[Sonnie Parker]

UPDATE: For a better step by step guide using the latest C-DSP and Dirac Live 3 software, see this updated thread:

miniDSP C-DSP 8x12 DL Tuning Step by Step Guide

I created a thread back in August 2019 on tuning my 2019 RAM with the miniDSP C-DSP with DL, but several things have changed since then, and I decided I'd do another write-up on how I've tuned my 2020 RAM truck. Disclaimer: This is not chiseled in stone by any means, and it's not necessarily...

www.avnirvana.com

I have my system installed in the 2019 RAM and I've been playing around with the C-DSP processor for several days now. I've probably ran a couple of dozen setups in various ways, and finally found what I think to sound the best... and it's flat out really good for a vehicle. I'm not sure how it can get any better than this, shy of one of the sho-nuff pros doing a pro tune on it, then I don't really know that they would improve on it significantly. Steve Cook at AudioX (won all kinds of SQ records) installed and tuned my wife's Lexus (some of you have heard it) and my truck smokes it. That's not to say that Steve couldn't do an even better job today than he did 5-6 years ago on her Lexus, so I'm certainly not discounting his abilities in any way whatsoever. I don't credit the sound of my truck on what I have done, but rather what miniDSP and Dirac Live have done.

It's somewhat of a process to setup the miniDSP and run Dirac Live, as it requires a computer, 3 different programs, the miniDSP UMIK-1 mic, and you have to have your vehicle close enough to an Internet connection to run Dirac Live.

I will try to outline this step by step for those that might later want to give it a try and may not be aware of what all is required. There are a couple of variations and I may not have everything perfect, but it sounds really good, so I'm apparently getting it at least pretty close to right.

My system consist of dual 10" subs in the rear under the seat running 25-80Hz, front door midbass 6x9 speakers running 80-350Hz, and front dash 3.7" speakers running 350-18kHz full range... then two 3.5" rear fill speakers above the rear window in the headliner running 350-3500Hz R-L and L-R with 20ms delay -6dB output,

This is the setup that has worked best for me after a good bit of trial and error... yet I can't help myself... I want to keep on trying to improve it, but this is pretty good none the less.

I am running Toslink digital optical from the factory radio via the PAC AmpPro4 to the miniDSP... basically a full range Left and Right signal. From the miniDSP... channels 1 and 2 are sent to the amp to power the Dash speakers, channels 3 and 4 are run to the amp to power the Door speakers, channels 5 and 6 are to a separate power amp for the rear fill speakers, then channels 7 and 8 are to the main amp for the subs.

Here are how the channels are routed in the C-DSP software... Inputs & Bass Mgt tab and Routing tab...

You will notice that channels 5 and 6 are set at -6dB and then L-R and R-L for a rear differential setup. The green -6dB indicates the speaker is phase inverted. If you right click on the block, you get this:

This is all explained in more detail on page 35 of the C-DSP manual. Basically use this setting prior to running Dirac Live... and after running DL, then setting the crossover to about 350-3500Hz and the delay to 15-20ms will give a better ambience rear fill to help with the sound stage in the front. It does seem to help in my truck... as I can tell without it that it does not seem quite as full as it does with it. Although I also notice if I give the rears too much volume, it starts to pull the stage towards me and away from the front, so there is that perfect level that I have to get it to for it to sound right.

Initially I leave every speaker separate and simply set the crossovers for each speaker... so the Mixer tab in the C-DSP program looks like this:

The only thing really different here is the output for channel 7 and 8 are combined for the SUB channel. All of the channels in the left column are exactly as they are connected from the outputs of the C-DSP... and are sent to the amp channel that is powering the corresponding speaker channel that is labeled across the top. So Dirac3 is sending signal to the L DOOR speaker, and Dirac4 to the R DOOR speaker... etc.

Next I set the crossover for each speaker... I do NOT set the delay at this point.

You may be asking why I set the dash speaker to cut off of 18kHz. Their response is rated to 18kHz, so I cut them off there... probably wouldn't matter, but I do it anyway. I can't hear anything above about 12-13kHz, so it certainly won't ever matter to me.

Now that I have the crossovers set, I am ready to do nearfield measurements on each speaker. This is not a required step, but I promise you it helped me get a better sound and blend between all the speakers... and solved some issues I was having with some frequencies, particularly in the midbass. I could not resolve the issue without first doing a nearfield and primary seat pre-tune. It may work for you without having to do this, and if it does... awesome, but again, this worked better for me, and I have read where it has helped others as well. IT IS NOT NECESSARILY REQUIRED.

Using REW (the free program you get here at AV NIRVANA)... I used the Generator in REW and recorded about 2 minutes worth of Periodic Pink Noise to a USB thumb drive to play thru my headunit. You might want to record 5-10 minutes, as I found myself constantly have to reach up from the back seat and press the back button on the headunit.

I then disconnected all the RCA outputs on the miniDSP other than the channel I was measuring... changing each output as I changed speakers to measure.

I connected my UMIK-1 mic, loaded the calibration file and placed the mic a couple of inches in front of each speaker for the measurement... then played the pink noise and used the RTA in REW to record the response, saving it as a measurement to REW.

Here are the settings I used for the RTA...

As I place the mic near the speaker, I play the pink noise, then click the red record button on the RTA and get about 20-30 averages before I stop. Once you have stopped recording, then you can save the current measurement to the REW screen for viewing, smoothing, etc. As you can see below, I got 25 averages and then clicked Save Current.

After measuring my sub and clicking Save Current, this is what I see in REW...

I could here the thud in that 50-60Hz region which was keeping me from getting that smoother sounding bass I really like. I am not sure why, but Dirac Live by itself was not doing a good enough job of removing it... mainly because at the primary listening position, it wasn't being measured as drastic as it looks here. None the less, lowering that area definitely helped the bass improve. I opened up the C-DSP program, then opened the PEQ for the SUB and entered in a filter to get rid of it. The nice thing about this is you can run the RTA while you are making the adjustment in the PEQ settings and see the result in the RTA. After you add or adjust the filter, simply stop and restart using the RTA red record button to quickly see the changes that your filters are making. Experiment with the frequency, gain/cut and Q factor to see what works best.. and in some cases you may need more filters.

This is what I ended up with for my SUB...

Then I moved on for the other speakers... mainly to make sure the vehicle cabinets for the speakers weren't doing anything weird to the speakers... doors looked really good nearfield...

I did not do anything to the doors... and I did not make any adjustments to the dash speakers, since I was surely picking up reflections from the window as well... but here is what the dash speakers looked like... 1/6 smoothing applied...

Next I wanted to get the measurements for each speaker at the primary listening position... so I measured where the center between my ears would be from the roof, left window and steering wheel... and setup my tripod with the mic tip where it would match up to the measurements... 10" from the roof, 16" from the left window and 22" from the top of the steering wheel... this is where the center of my head is with how I normally sit and drive. I checked it several times getting in and out... amazing how I hit the same spot over and over.

So I go back to the RTA in REW and using the same periodic pink noise that I recorded, I play it thru each speaker and record the measurement from the primary driver's seat. Here is my sub... red is prior to filters and green is after filters... fixing a few points to smooth it out...

Left door with 1/12th smoothing... knocked down that really high points... and this eliminated some midbass distortion I was getting on some songs with heavy midbass in that 100Hz area... it was like a loud drone noise on certain notes... and not sure why Dirac Live wasn't fixing it, but this worked... problem solved... for both front speakers... as you can see in the next two images...

Right door before and after...

Left dash speaker... did not do a lot here, mainly knocked down the high points a little... and did not worry about the 15kHz peak since I can't hear it anyway...

And right dash...

That finishes up with the pre-tuning using the PEQ filters to straighten out some high points.

In the next post I will go into detail on how I perform the Dirac Live measurements and make the necessary adjustments in the C-DSP program.

 

[Sonnie Parker]

Next up is measuring with Dirac Live. This requires an Internet connection and the Dirac Live software.

The first thing is making sure I am still on the same Configuration (Config) in the C-DSP... and the only thing set in the C-DSP is the crossover points for each speaker, and the PEQ's for the pre-tuning I did.

SHUT down the C-DSP program for now.

I want to first get the delay for each speaker. This can be accomplished by either physically measuring from your head area to each speaker and inputting the delay for each measurement, or you can run Dirac Live and let it tell you what it is, which is what I did.

I am sitting in the back out of the way while performing the measurements

Start up the Dirac Live program and select Custom ... and since I have 7 speakers, I select 7. Then after making sure your UMIK-1 is connected to a USB port on your computer, select the Mic. Then you will check the levels for each speaker and make sure they are okay. No reason to rename any of the speakers at this point, as this is merely a preliminary run for delay measurements.

Again... I setup my UMIK-1 in the same position I had it for my pre-tune measurements... center of where my head is when sitting in the driver's seat.

Run the first set of sweeps and Proceed to the Optimization part... no need to run anymore positions at this stage, unless you have already input your delay measurements, then you can run more positions, in which case you might want to skim on thru this section on delays.

After optimizing, save your project and load it into a preset. Then go back to the C-DSP program and open up the Dirac tab... copy down the delay measurements for each speaker and go over to the Input tabs and enter in the delay ms for each speaker. This is the Dirac tab. I did not save this part, but you will see the ms of delay on this tab...

Enter the delay for the corresponding channel on the Output tab... DO NOT enter any delay for the rear speakers or the sub at this point...

After entering the delay, now you are ready to mix your channels to create a two channel system with the subwoofer and rear speakers... so basically a 4.1 channel system if you use rears... LEFT FRONT, RIGHT FRONT, SUBWOOFER, LEFT and RIGHT REAR.

Notice above on the Mixer tab I have moved channel 3 and 4 up to 1 and 2 and combined the door and dash speakers for each side... left and right. I left my rears where they were, and the SUB as well. What happens now is when the Dirac Live sweep runs, it will sweep from the door up to the dash combining the measurement for the door and the dash speakers... similar to how you would measure a full range speaker in the house.

If you have a 3-way system you want all three drivers on channel 1 and 2 for left and right.

Turn Dirac Live OFF in the C-DSP... save your settings to your preset and quit the program.

Now it's time to run Dirac Live again. This time you will select 5 channels for the Custom setting... or 3 if you have no rear fill speakers. Make sure you select the proper channel for your speakers...

Notice that I have changed the LEFT REAR and RIGHT REAR channels to Output Channel #5 and Channel #6... and the SUB to Output Channel #7... since that is how my Routing and Mixer tabs are set.

Now when I run the measurement sweeps, it sweeps the entire front left, front right, left rear, right rear and subwoofer, then one more time on the left front. I keep my mic centered where my head is for the first two measurements... then I moved it slightly left, slightly right... slightly backwards, forwards... up a little, down a little... you can experiment, but it seems to be the consensus that taking more measurements is better. It is not averaging... it is looking for areas to fix anywhere around your head... or anywhere you are placing the mic. Some guys are even taking a measurement over on the passengers side. I have not tried this yet, but probably will eventually.

So after my measurements... this is what I see for the sub...

.... and the fronts...

Target curves are subjective for the most part, so trial and error is expected, but typically keeping the target below the problem areas works out best... so there is not much boosting going on. However, you may have to increase your amp gains prior to tuning your system, as this will reduce your overall volume level... considerably in my case. This will also help with the bass levels, which typically need to be a good bit higher in vehicles to overcome road noise.

After running all the measurements, setting your target curve, then you are ready to optimize, save your project and load it into the C-DSP.

Now you can hop in the drivers seat with your laptop, as you will need it.

Once loaded, open up the C-DSP program again and look over the Dirac tab to make sure you don't see anything abnormal. The delay should be close to 0 for each channel other than the rears if you have them... they may be 4-5ms or whatever the distance is.

Go to your Output tab for the rear speakers if you have them and set their crossovers, and set the delay to 20ms to start with. You may want to reduce the output to -6db for now and adjust as necessary later.

This is when I will take a recorded 80Hz tone and play it thru my headunit... then on the Output tab for the SUB, click on the invert block... and set the delay to 20ms. Playing that 80Hz tone/sinewave, start reducing the ms using the down arrow next to the setting. See below...

As you reduce the ms of the delay, the tone will get softer and should start moving behind you and center of the vehicle at it's lowest tone. Mine was lowest and centered in the vehicle behind me at about 14ms. Once you are there... click on the Inverted green block and you will notice how the bass jumps in front of you. Now you are ready to give it a try and see how it sounds.... making minor adjustments if necessary, although not much should be needed. It is better not to create any other PEQ filters or change the crossover settings at this point.

I'll double check this later to see if I've left out any major steps or can improve on it, but that is pretty much it. Enjoy!

Before I removed my mic, I took another REW measurement from that primary spot where I took the first measurement. Using the periodic pink noise playing thru all of the speakers (rears reduced)... I captured the response via the RTA and saved it as a measurement. Remember that it won't be perfect because I moved the mic around, and for this measurement, I'm not moving the mic... it is stationary, as well as I measured each speaker, this is all of them playing... SUB, LEFT FRONT AND RIGHT FRONT. It will be close to what you are hearing. This is 1/6th smoothing...

 

[LayinLo]

Thank you for this write-up!

 

[Sonnie Parker]

You bet!

I need to post my latest settings. I tried combining my subs with the front and now only use 2 channels that include the sub in the tuning sweeps. 2 channels front and 2 channels rear fill. Sounds better... not drastically, but enough to make me want to leave it like it is.

 

[Andrew Slater]

Very nice sonny !

 

[dengland]

Subbed. Thanks for the write up. Probably heading down this path for the HK "19" speaker "Premium" in my 2020.

 

[Sonnie Parker]

Thanks guys.... got more to post, but super crazy busy at the shop for now. I hope to get back on it after the first of the year.

 

[Trong Le]

Subbed. Thank you.

 

[phatfos1]

Anything to add, Sonnie? I am going to give this a go when the 8x12 DL arrives next week.

 

[Sonnie Parker]

I haven't had time to do anything in my room. I have a lot to setup that has come in that has sit for 3-4 months now. We have been overwhelmed here in the gun business... it's been crazy. I hope I'll get some more time later in the summer to work with it some more.

EDIT: I just realized this is not about my room, but about my truck... duh!

Of course the answer is still the same.

 

[phatfos1]

I also found that the response is better when Dirac treats each speaker group as one speaker. It does a better job at the crossover points/integration. In your Dirac tab just have Dirac 1 (left) and Dirac2 (right) with the sub on for both. Attached is my average response and another graph showing all the sweeps.

 

[Sonnie Parker]

Yep... I was skeptical of this at first because the folks at miniDSP kept telling me that is really not how it was designed to work, and not what they intended, but it works better, so it's the way to go as far as I and many others are concerned.

As much as I love this system... I don't think I can do it again... it's just too much work. I'm trying to trade for a 4WD model... same identical everything except the drive-train. I'm about 5K upside down, so I'm not sure I'm gonna bite off that amount just yet, but with 0% financing it is tempting for sure.

I have to say though... the miniDSP/Dirac Live setup has made this truck sound better than any stereo in a vehicle that I have EVER had in my lifetime of installing very serious systems in a dozen vehicles. I'm not sure how it could get any better sounding in a vehicle. It is absolutely marvelous... but it's a LOT of work, and at the sacrifice of a little more quietness in the vehicle than I like. I'm use to it now, but when you get in another one of these trucks without the stereo, there are two distinct differences you notice... the factory stereo, while not that bad, is just no where close to the miniDSP/DL system. And second... my truck is not as quiet as the factory. There is give and take.

I keep wanting to play around with the triple voice-coil connection of the factory sub to see if I can plug JUST the ANC portion of it up without the sub portion, but I haven't done it yet, as it is going to take some trial and error to figure out which two of the 6 wires is the ANC and be able to ride down the road with a rigged switch to turn it on and off to discover the effects. If I don't trade... maybe one day. If I do trade, I probably won't ever find out.

 

[phatfos1]

Yep... I was skeptical of this at first because the folks at miniDSP kept telling me that is really not how it was designed to work, and not what they intended, but it works better, so it's the way to go as far as I and many others are concerned.

As much as I love this system... I don't think I can do it again... it's just too much work. I'm trying to trade for a 4WD model... same identical everything except the drive-train. I'm about 5K upside down, so I'm not sure I'm gonna bite off that amount just yet, but with 0% financing it is tempting for sure.

I have to say though... the miniDSP/Dirac Live setup has made this truck sound better than any stereo in a vehicle that I have EVER had in my lifetime of installing very serious systems in a dozen vehicles. I'm not sure how it could get any better sounding in a vehicle. It is absolutely marvelous... but it's a LOT of work, and at the sacrifice of a little more quietness in the vehicle than I like. I'm use to it now, but when you get in another one of these trucks without the stereo, there are two distinct differences you notice... the factory stereo, while not that bad, is just no where close to the miniDSP/DL system. And second... my truck is not as quiet as the factory. There is give and take.

I keep wanting to play around with the triple voice-coil connection of the factory sub to see if I can plug JUST the ANC portion of it up without the sub portion, but I haven't done it yet, as it is going to take some trial and error to figure out which two of the 6 wires is the ANC and be able to ride down the road with a rigged switch to turn it on and off to discover the effects. If I don't trade... maybe one day. If I do trade, I probably won't ever find out.

Yep... I was skeptical of this at first because the folks at miniDSP kept telling me that is really not how it was designed to work, and not what they intended, but it works better, so it's the way to go as far as I and many others are concerned.

As much as I love this system... I don't think I can do it again... it's just too much work. I'm trying to trade for a 4WD model... same identical everything except the drive-train. I'm about 5K upside down, so I'm not sure I'm gonna bite off that amount just yet, but with 0% financing it is tempting for sure.

I have to say though... the miniDSP/Dirac Live setup has made this truck sound better than any stereo in a vehicle that I have EVER had in my lifetime of installing very serious systems in a dozen vehicles. I'm not sure how it could get any better sounding in a vehicle. It is absolutely marvelous... but it's a LOT of work, and at the sacrifice of a little more quietness in the vehicle than I like. I'm use to it now, but when you get in another one of these trucks without the stereo, there are two distinct differences you notice... the factory stereo, while not that bad, is just no where close to the miniDSP/DL system. And second... my truck is not as quiet as the factory. There is give and take.

I keep wanting to play around with the triple voice-coil connection of the factory sub to see if I can plug JUST the ANC portion of it up without the sub portion, but I haven't done it yet, as it is going to take some trial and error to figure out which two of the 6 wires is the ANC and be able to ride down the road with a rigged switch to turn it on and off to discover the effects. If I don't trade... maybe one day. If I do trade, I probably won't ever find out.

So you think I should put my target curve below my dips? I see you put your curve -10db down. I just left mine where it was by default around 0db which then required boosting in many places. Let me try that....

 

[Sonnie Parker]

You could try it and see. It's always been my preference in my home because it's easier to cut peaks than it is to boost dips, although I would not let the very narrow serious dips be of any concern. Our ears won't ever notice most of those anyway.

 

[phatfos1]

I just went back and read the active speaker section again on pg 37. They do want you to do Dirac Live with one channel for all speakers on each side (eg left woofer, mid, tweet + sub) in an active setup. This is so Dirac can better correct for phase issues at the crossover points. So in my system after I did my rough calibration and correction in REW for each individual driver I did my Dirac sweeps with everything playin together on the left and everything on the right.

 

[dengland]

Which HU is in your 2019?

 

[Sonnie Parker]

I'm sorry... were you asking me? It was the 8.4 in the 2019... https://www.avnirvana.com/threads/2019-ram-1500-laramie-crew-cab-system-build-project.5146/

I traded up for the 2020 4WD model and it has the 12" display in it.

 

[dengland]

Thanks Sonnie. I will reply in the other thread.

 

[Sonnie Parker]

I MUST be CRAZY!!! ... I AM crazy!!!

I just ordered another miniDSP after selling mine. I should have kept it. lol

 

[Sonnie Parker]

I have updated the miniDSP tuning process to include the latest software versions as of this posting in July 2020.

miniDSP C-DSP 8x12 DL Tuning Step by Step Guide

I created a thread back in August 2019 on tuning my 2019 RAM with the miniDSP C-DSP with DL, but several things have changed since then, and I decided I'd do another write-up on how I've tuned my 2020 RAM truck. Disclaimer: This is not chiseled in stone by any means, and it's not necessarily...

www.avnirvana.com