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Discussion Starter · #1 ·
Hey folks,

After learning so much from various forum members, scouring through (and contributing on) many threads, and being probed by my peers (and superiors) to document the process, I have written a simple tuning guide for folks wanting to use Dirac Live via the MiniDSP C-DSP 8x12 DL.

It is primarily composed of ideas developed/curated by DIYMA members Truthunter and oabeieo, with revision assistance from bertholomey, naiku, and squiers007.

I hope you all find it useful, and if you have any questions or feedback, please drop a reply here, and I'll amend the doc accordingly.

I'm sharing it here as a google doc, that way anyone viewing it will always be looking at the latest revision:
MiniDSP C-DSP 8x12 DL (Dirac Live): Quick Tuning Guide

Thanks, and enjoy!

PS: These two threads contain a lot of the background that went into writing this guide:
Dirac tips and tricks
MiniDSP C-DSP 8x12 with Dirac Live
 

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Discussion Starter · #11 ·
I've read through the document, it is clearly written and seems easy to follow. I will be a good test case I suppose.

I did have one question about HPF for sub channel. As I understand it, one is never applied. There is mention not to place the left-hand curtain too far below the tuning frequency of a ported box, but as far as I understand, the curtain is not a HP filter. How is the sub protected if there is no filter applied?
Good question! You're correct that, in the example in the guide, we didn't set an HPF (or infrasonic filter) on the sub. Despite me running my 2 SQL-12s ported, I'm not pushing the subs anywhere near excursion limits, even below the tuning frequency (30Hz, in my case), so I didn't set an infrasonic filter. I just made sure not to boost down there.

In your case, I think you would want to add a HPF onto the sub output. You could also cascade that HPF onto the mid-bass's output (we have an unused HPF on those outputs as well).
 

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Discussion Starter · #12 ·
I've read through the document, it is clearly written and seems easy to follow. I will be a good test case I suppose.

I did have one question about HPF for sub channel. As I understand it, one is never applied. There is mention not to place the left-hand curtain too far below the tuning frequency of a ported box, but as far as I understand, the curtain is not a HP filter. How is the sub protected if there is no filter applied?
Actually, after talking with @Truthunter , an easier option would be to set the infrasonic filter prior to Dirac, that way you don't need to cascade it. I amended the guide accordingly. See: 4.e.iii.1
 
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Discussion Starter · #15 ·
This is pretty cool man, thanks for spending the time I reposted it on the Mini DSP forum , hope you don’t mind it’s really we’ll done

and seriously thank you for spending the time for us. I will be referring a lot of people to use that that’s a really good write up. Awesome contribution thank you



Already did

this will help a lot of folks

I shared it here

Minidsp thread
Thanks for your contribution, Andy! Your "no crossover" approach to running Dirac was a game changer
 

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Discussion Starter · #33 ·
maybe shoot minidsp an email, as I suspect the higher-ups aren't that interested in the forum on their site, tho devteam certainly pitches in :)

This is kind of a big deal and needs to have a link to the document on the product page, possibly the manual? a link that is, live document and all :cool:


Bravo on the guide otherwise, really clever work in there.

Also, in 6.b.ii.4.a of the guide, "do not apply a hpf" .... is that to say, bypass the hpf we set in 4.e.iii.1.b ?
Updated 6.b.ii.4.a accordingly; you would want to leave the infrasonic filter you set in 4.e.iii.1.b in place
 
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Discussion Starter · #35 · (Edited)
Greatly appreciate the guide and everybody's contributions to it.

I have a few questions:

Why the do you recommend a 1.25 x fs BW12 protective crossover. Why BW12 over LR12?

How will the protective crossover BW12 affect the tweeters phase and actual crossover if using LR24 electrically?

With an Audiofrog GB15, this puts the protective crossover at about 1480hz really close to the recommended minimum crossover of 1800hz.

Can I just use a sharper slope at one octave lower then desired crossover frequency if the measurements are not to loud?

I ask all this because it was my impression from the manual that Dirac cannot correct for phase through the crossover when using separate Dirac channels per driver vs 1 channel left drivers and 1 channel right drivers.

I figured two different crossover types BW12 and LR24 on the same driver at different frequencies would mess up phase.

Thank you.
The protective XO guidance is simply to help you protect your tweeter from blowing during the sine sweeps. You can certainly use a different frequency or XO type/slope. It was just a basic way to come up with a reasonable protective XO, for those who might not have any idea on how to pick a protective XO. I didn't personally follow the 1.25 x Fs that I put in the guide, as I'm using a protective cap, from my last set of tweeters. The main thing is to keep it low enough that it won't impact the actual HPF that you use for your tune. Dirac won't need to correct phase through your protective XO if it is low enough
 

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Discussion Starter · #36 ·
:oops::oops::oops:

I just finished my first successful Dirac tune and WOW. I am impressed and excited! I didn't think it would go so well on the first try. Detail is the best I've heard in any of my systems to date, imaging is good and the stage is huge. I am hearing more resolution in songs I've listened to hundreds of times on many different stereos. Vocals sound more real. Midbass has more clarity. High hats sizzle above my head like a sonic veil (no exaggeration - it's incredible!) and it sounds like there is a kick drum inside my engine bay haha. I can't wait to continue messing with this technology!! I'm doubtful I'd ever be able to get a tune like this manually.

Side note: one thing I find weird about the 8x12DL is that the sin sweeps are fed directly from your computer to the DSP, never passing through the head unit. As such, any coloration in your system upstream of the DSP is not accounted for.

I want to give some feedback on the Guide here too. Overall I found it strikes a good balance between completeness and conciseness.

My front stage is 2-way, just midbass and tweeters, so I adapted the guide accordingly. In the Dirac Channels Configuration step, I used "Small/Bass Managed" for the mids (step 4fii) since neither woofer nor midrange seems appropriate. Not sure how much of a difference this makes. I think it would be useful to remind users here to set unused channels to Unsued in this step since Dirac will error otherwise.

In step 5diii, it could be useful to be explicit about what meter should be monitored to hit the -20 to -25dB target. In this case I think it's the mic gain's meter.

When loading the target curve in 5gi, it would be useful to add that the target curve should be applied to All Groups.

Setting the curtains is a little subjective and some users may find some more guidance by example useful at that step. Same goes for selecting crossover points.
Glad you got a great tune!

Thanks for the feedback. I updated 4.f.iii and 5.g.i accordingly. I was trying to avoid getting into XO points in this guide; my thought process is, if this becomes a 10+ page guide, it will become too daunting for most beginners. Open to reconsidering, though.
 

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Discussion Starter · #39 ·
My front stage is 2-way, just midbass and tweeters, so I adapted the guide accordingly. In the Dirac Channels Configuration step, I used "Small/Bass Managed" for the mids (step 4fii) since neither woofer nor midrange seems appropriate.
Currently, Dirac doesn't do anything with that speaker size; it's going to run the full sine sweep for all channels. Maybe later on they'll use it for something.
 
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Discussion Starter · #53 ·
yes!!! You know what it is when tge tune is so dam good and everything is just so amazing….. and it’s flat out Spaceship!!! Yes!!! Hahahahaha!

if listening to your system makes you feel like if you walked out in your front yard and saw this, then it’s awesome! Gloryhole spaceship mode is my fav


View attachment 330071
Lol @ "gloryhole spaceship mode" as a descriptor for what's going on here
 

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Discussion Starter · #56 ·
Sort of like aliens walking in on you while you’re jerking off. Hahaha
This is how I would describe a really bad tune
 

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Discussion Starter · #61 · (Edited)
just reposting my question here... will this guide need a revision due to any method changes in the newest Dirac release?
Yea, it would need changes to the portion about setting the target curve. The current guide still holds true since it has a (still applicable) step for uploading your own custom curve, so that can still be fully used.

The only change that could be made is to take advantage of the new default curve function, which would simplify the guide a bit (i.e. no need to upload your own custom curve now). I'm hoping to try out the new default curve UX this weekend, and I've already been in touch with the other contributors on the Guide, so hoping to modify the guide some time next week.
 

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Discussion Starter · #63 ·
So far, I've tried the new curve functions. While they're good, they still leave some issues. Using the custom curve either leaves my car with too much mid-bas, or too little sub bass. Granted, I have a tiny car (NC Miata), but I need a little bit different blend to get it to work for my car. The upper range roll off is nice.

I've still needed to use custom curves, but the "defaults" are now very usable as starting points. Given that in a home environment, you don't need the large bass boost, it makes sense how they did their curve. In a car (or at least mine), I need extra below 60Hz to compensate for cabin size, and the roll off to 200Hz has too much mid-bass.

I'd wager in a larger cabin, this is less pronounced, of an effect, but we'll have to wait until more folks try this out and report back.

EDIT:
Just looked up, so my Miata is ~5 feet wide, and definitely shorter than that in length of cabin, as trunk is completely isolated. This means my cabin gain starts around 100Hz, vs a "normal" car which has major cabin gain between 40-60Hz (8-12 ft length of cabin).
I didn't get around to testing the new default curve this past weekend, but curious to see. I have a 2dr Jeep, which has a small cabin as well. Perhaps not as small as yours, but if you couple this with my preference towards a lot of sub bass, I suspect I'll have similar issues to you. My current target curve (for daily listening, not competitions) has about an 18dB difference between highest sub bass level and lowest high end level. And the new Dirac default curve allows up to 15dB difference
 

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Discussion Starter · #65 ·
The default target ive tried several times now
It works really well….

On my CM-10 mic it sounds so good. It sounds like it fits the room and the responce actually sounds like I would expect from the target. The CM-10 I believe gives Dirac that last bit that makes it what I believe it was always meant to be. Especially in tonality! Hands down cm-10 wins (big time)


on the umik1 it has too much midbass and is muddy imo (ever so barely I might add)

on my UMM6 same thing as umik1 except the highs are brighter a little so it makes up for what sounds muddy to me

the umik1 and UMM6 on a perfectly flat target sound proper and sound good….

I’ve tried this on 2, 8x12s, a flex, and a ddrc22
All same results, all different “rooms”
The flex is in a big room and it also shared the same attributes as the others that were in car.

ive ordered a umik2. We will see how it measures.
Let me know how the UMIK-2 compares to the CM-10 with Dirac measurements. I've currently been using a UMIK-2.
 

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Discussion Starter · #67 ·
@Anu2g - did you ever use a UMIK-1? If so, any comments on it vs. the UMIK-2 in terms of tuning results?

@oabeieo - how are you connecting the CM-10 to your PC?
Yea, I started with the UMIK-1. I wouldn't be able to give you a good comparison because I had learned a lot more about how to use this DSP and tuning in general in parallel with switching mics, so it's hard for me to say whether that increased knowledge or mic change made the difference in making my tune sound better. I would lean toward the former. It wasn't a scientific comparison.
 
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Discussion Starter · #72 · (Edited)
Mind posting up your curve?
Again, this is just my personal listening preference / daily curve, however this isn't the same curve I'd run for demos. Also I should note that this is in a 2-dr Wrangler, i.e. my cabin is pretty tiny.

Rectangle Slope Font Line Parallel
 

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Discussion Starter · #97 ·
So I got the 8x12 in and the tonality is absolutely to die for.
But I'm having an issue with the stage sounding like it's coming from the pass side (L) speaker location....any ideas gents?
Can you attach a pic of your Dirac tab?
 
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Discussion Starter · #99 ·
The one on the minidsp software? Or the actual dirac software?
From the C-DSP Plugin. You'll need to be connected to the DSP to get that screenshot. If it shows all zeros for the Delay then that would definitely explain the issue and, unfortunately, you'll need to remeasure. It appears to be a bug in one of the newer versions of the software.
 

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Discussion Starter · #106 ·
If you verify what Dan said and that's not the issue, you may want to go into the Dirac software, open up your project, go into the Filter Design step and view the actual corrected impulses to make sure it didn't flip a driver out of phase.

You could also listen to driver pairs to see if that makes it clear what is off.
 
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Discussion Starter · #110 ·
Edit
Nevermind, went back and read it and I must have missed it lol.
When the guide says lean the seat back and take your first measurement at the top of your nose...are you taking it where the tip of your nose would be in your typical seating position? Or at the top of your nose while leaned back??
Tip of the nose in typical seating position. Or between ears is what oabeieo does (in typical seating position)
 

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Discussion Starter · #113 ·
My file names I use th3 name or date, mater volume level, and sometimes any specific info to that calibration……

like for example tonytundraLFvol47config1
TonytundraRFvol42config3
I do something similar, but I don't prepend the name of the person or the car for obvious reasons (they're constant). I keep a Tuning folder, with subfolders for each date that I tune, and then I have a Pre Config.xml which is my config before any Dirac measurements, and then a file for the config post measurements. For the Dirac measurements (not to be confused with Plugin Configs), I name it based on what I'm doing and any output adjustments I might have done before measuring (I.e. Windows Down - Sub minus 20db).

So a full path would look like:

/Tuning/20220627/Windows Down - Sub minus 20dB.liveproject

If I was testing, say, measuring at 0 degrees instead of 90 degrees, it would be:
/Tuning/20220627/Windows Down - Sub minus 20dB - 0 degree.liveproject

This topic might require another thread, though.
 
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