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Discussion Starter · #1 ·
I've been searching for a resource on this topic or even a discussion but haven't found any. Please point me to one if it does exist, but in the meantime I will ask my question and hope someone has experience with both PEQ and GEQ DSPs. I'm wondering which has better ability to dial-in response for a car audio system. The trade-off seems to be GEQ has 31 bands but at pre-determined, fixed frequencies. PEQ allows you to choose the center frequency and Q arbitrarily, which is a definite advantage, but tends to be limited to say 10.

Specifically I'm comparing a Helix V.Eight (31-band GEQ) to a MiniDSP C-DSP 8x12 (10-band PEQ). The MiniDSP can also run custom biquads (also only up to 10) which allow weirder transforms than simple PEQ. So it would seem to be more flexible but would it result in better sound? Or would the 31 band GEQ somehow have an advantage simply because it has more tweak points? Another advantage of the MiniDSP 8x12 is I can pay for the Dirac Live license if I'm not happy with the self-tuned version. I'm coming from a MS-8 (which I stupidly sold...), and I really liked what it could do with a soundstage.

I think I'm convincing myself that I want the MiniDSP but it is more expensive because the amps are separate. Thoughts welcome!
 

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Get both with helix dsp. 31 geq or 31 peq.

Peq has large advantage when needing to shape your acoustical crossover perfectly to a 24 lw slope. At only 10 peq you can quickly run out.

Sent from my SM-N960U using Tapatalk
 

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I used to have a 31 band dsp with adjustable q. Got great results with it. Now have a minidsp cdsp6x8 and have gotten great results. The advantage of the peq is the ability to dial in certain frequencies and adjust the q narrow or wide. A single peq band can take down an entire peak where as you may have to get creative with a 31 band with no adjustable q.
either will work but just approacha bit differently.
I will say I have been toying with getting a minidsp 8x12 and upgrade to Dirac live if necessary.
the helix units have the auto eq function as well. But I think it’s on the higher end ones.
but I am simply not going to spend 1200+ on a dsp when you can get great results with a minidsp wth Dirac for 899.
but everyone’s budget is different.
I saw a video on the auto eq function of the helix and it was crazy how you can dial a car in under 20 minutes.
I guess you can do the same with the minidsp after you play with it a bit.

but the preference for most is peq over geq.
I used rew for both platforms and got very similar results.
 

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Discussion Starter · #6 ·
Hang on, you guys are suggesting that the Helix has PEQ in addition to the standard 31-band GEQ? I didn't see that in the manual, at least for the V.Eight MK2. That would be best of both worlds, cheaper than the miniDSP (because of integrated amps). But no DiracLive option. I wonder how DL compares to Helix autoeq...
 

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I don't know about that model. You can download their tune software, select the unit you want to buy as the demo and see if it lets you select peq.

Sent from my SM-N960U using Tapatalk
 

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Discussion Starter · #8 ·
Great, I'll try that.

In the meantime, any suggestion on many-channel (4-8) amps with not much power and good SQ that don't break the bank? Actually that should be a new thread...
 

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I actually saw a place in CA advertise the DSP.3 online for $700. One of the only places I could find it online in the US, to be honest. You can also get them on Ebay from Poland, Italy, etc for ~$550 (I paid $535 shipped for my DSP.3 - brand new, with warranty though seller) - arrived in a few days. Honestly, I don't think I've ever needed warranty service for any electronic item - ever. Usually, electronics are DOA or last a long time in my experience.

Also - just to clarify - Helix DSP.s have 31-bands per channel - you can configure each band to be either GEQ or PEQ - but you don't get 31-bands of both GEQ and PEQ. You can mix and match or use them all as PEQ or GEQ though. I have some coaxial speakers with wide frequency ranges and I do use more than 10 PEQ bands on some channels. Right or wrong, it works well for me and my system. Allows me to better match my target curve and left/right more closely.
 

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You have to call around and see if local shop is helix dealer. Cost at my local dealer was 700. If you want to buy online you can contact skizer on this forum from Apicella sound. He'll ship to you.

Sent from my SM-N960U using Tapatalk
 

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Arc PS8pro allows you to use geq and peq at same time.
You can shape. Cut,boost whatever and however you want
 

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Discussion Starter · #13 ·
Based on the software, @jrwalte and @jtrosky were correct! Helix V.Eight MK2 can select each of the 31 bands individually as GEQ (with tweakable frequency) or full PEQ. It's way better and more capable than I thought. I can't load custom biquad coefficients but that's no problem. The only question is whether I'll miss not having Dirac Live. Anyone have an opinion on that?

Also I just realized that the Helix is 64-bit and miniDSP is 32-bit (dunno if it makes a difference). And to muddy it further, the miniDSP runs at 192kHz if just doing PEQs but drops to 48kHz if you load the Dirac plugin. Helix is always 64-bit and 48kHz.
 

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I saw a video on the auto eq function of the helix and it was crazy how you can dial a car in under 20 minutes.
Just remember, the Helix auto-EQ still requires you setup things like time alignment, crossovers and levels "manually". That all needs done properly before the auto-EQ, in order for the auto-EQ to work well - and that all takes time, especially if you are unfamiliar with the car, the speakers and/or have never used active crossovers before. You need to determine what acoustical crossover point(s) you want to use, take measurements, figure out what electrical crossover points will allow you to best achieve the acoustical crossover points, level-match all of the speakers, measure speaker distances for TA, etc.

Auto-EQ is just that - only EQ. Lots of other "stuff" that you still need to do manually. It's not a full "auto-TUNE".

Just don't want people to get the wrong impression that it only takes 20 minutes from start to finish to tune the car. Even with auto-EQ, it's still going to take some time for the other base-level "stuff" that needs setup before you can even get to the auto-EQ part.
 

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Arc PS8pro allows you to use geq and peq at same time.
You can shape. Cut
 

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Discussion Starter · #17 ·
Just wanted to say thanks to everyone for their helpful responses. It seems that Dirac Live is probably better than Helix DSP, but at the same time I'm feeling a lot more confident in the Helix capabilities. It seems that I would be happy with either system, and the Helix will be cheaper as it includes 8 amplifiers built-in. I was worried that Helix would be worse than the Logic7 autotune from the MS-8 that I'm used to.

Also FYI, the MS-8 totally wrecked the OEM echo cancellation for my Bluetooth phone calls. It was unusable. Maybe the Helix DSP would avoid that problem.
 

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Also FYI, the MS-8 totally wrecked the OEM echo cancellation for my Bluetooth phone calls. It was unusable. Maybe the Helix DSP would avoid that problem.
this is one of the main reasons audiotec fischer is hesitent to enable the FIR filters in their software. also, any of those 30 bands in the helix can be changed to parametric filters. it just starts off as graphic
 

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In a car , as far as a single left and right eq
A GEQ with a proportional Q (variable Q) filters with a fixed Q of about 4 is IMHO ideal

Proportional Q has better interpolation ( the side band of each filter can create a single wide Q filter if they all going the same direction)

Constant Q is what it says , constant shape and lacks interpolation ability. ( don’t confuse that with a constant shape filter or cosine filter)

Variable Q is preferred in SQ but does take some wiggleing the responce into shape with Live RTA

Constant Q will not be wider than the defined Q no matter if it’s 1db or 12db peaked.

The masconi 8to12dsp is a magnificent dsp IMHO. Uses constant Q on a geq that is parametric.

An opendrc with rephase will give you 8- 16band banks of eq (across each channel) and you can pick between , constant Q, proportional Q, constant shape, raised cosine, cosine, minimum phase or linear phase eq. And of course fully parametric. The opendrc2x2 with rephase is the best most versatile eq ive ever used.
 

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Based on the software, @jrwalte and @jtrosky were correct! Helix V.Eight MK2 can select each of the 31 bands individually as GEQ (with tweakable frequency) or full PEQ. It's way better and more capable than I thought. I can't load custom biquad coefficients but that's no problem. The only question is whether I'll miss not having Dirac Live. Anyone have an opinion on that?

Also I just realized that the Helix is 64-bit and miniDSP is 32-bit (dunno if it makes a difference). And to muddy it further, the miniDSP runs at 192kHz if just doing PEQs but drops to 48kHz if you load the Dirac plugin. Helix is always 64-bit and 48kHz.
Throw a ddrc22d upstream . That’s what I do , it works absolutely amazing
 
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