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It works very well. Using the DDRC22D into digital coax of my DSP Pro mk2.
What difference did you notice with the addition of the DDRC22D?
 

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TIME ALIGN EACH DRIVER USING MEASURING TAPE(on Helix or other DSP)

*optional*USE NULLING TECHNIQUE (Drop1’s METHOD)(on Helix or Other DSP)
I recently started doing this to fine tune T/A or phase. I perform it within each like pair of drivers first, then perform it again with like pairs against other like pairs. I use the front mid-bass drivers as the anchor for the system. I inverse polarity on the midranges and alter delay (been playing around with the method by either altering T/A or altering phase) until tones are most out of phase then flip midranges polarity back to normal. Next is to proceed to do the same thing except this time with midranges anchoring against the tweeters. I invert polarity on the tweeters and alter delay until tones are most out of phase then flip tweeters polarity back to normal. Lastly perform this step again with midbass as the anchor against rear fill drivers and subwoofers.
One of the advantages of the 8x12DL over using a DDRC inline before another processor is that it can automate this step: It can be set up using a Dirac channel per driver initially to provide precise time delay settings that can then be copied to another 2ch L/R config.
 

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So using analog inputs one would have to use a ddrc24 then analog only into a helix? There is no way to use to toslink in or digital coax hec card? Mini DSP needs to get on that if not.

Also would you use the helix to do remote?
 

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Has anybody ever heard of using 2 outputs with the same signal and reversing the polarity to double the output voltage of a dsp? Just like bridging an amp. Since 2 of the 4 outputs will be unused on the ddrc 24 I bought I was thinking I could double my voltage that way. Am I onto something or am I nuts?
Why would you reverse the polarity of one channel? Yes you are nuts but you arent the first to think of it

Just last week I was contemplating the same.
Since my amp takes 2 inputs to bridge (duh) I considered using 2 channels of dsp for each mid.
No doubt it would work but why? Amps have a low/high input and my helix can already put out an 8v signal.
It was neat to think about but I couldnt see any real value. The amp will only make as much power as it will make no matter how much voltage you force feed it.
This is the way amps are bridged. One has reverse polarity. So when one side swings up the other swings down. In effect doubling voltage.i copied this from Wikipedia for reference.

I was thinking that bacause the ddrc 24 only puts out 2 volts.
 

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What difference did you notice with the addition of the DDRC22D?
Since Dirac is performed while signal is digital I do not notice any degradation that one *might* experience with an extra AD/DA conversion.

It is purely a tuning tool. Within 30-45 mins you can get the image and stage pretty much spot on. Like when an eye doctor switches the lense apparatus and the line of letters you thought you could see with squinting, you can now clearly see with ease. Better cohesion amongst the drivers I guess? Still achievable manually but not in so little time.

I almost like now want to spend more hours toying with different ways of measuring the calibration measurements and trying different house curves rather than then spending time in REW.

Will it beat your manual tune you’ve been perfecting for a while with manual measurement and adjust via REW or your preferred measurement software?
Probably no, BUT it will come close and come close at a fraction of the time and effort it took one to do so.

The major caveat for me so far is that I did lose volume but that is to be expected with any Dirac Calibration product. -15db to -12.5db on my Helix Director with USB HEC is my tolerable louder listening volume. With DDRC22 into digital coax I have to turn my volume to the max 0db to reach that same volume and since things sound more cohesive/precise, I could actually stand to increase the volume by another 2-3db.

Gains are turned down on my individual channels in the Helix so I could increase all the channels by a couple dB even across the board to gain some more volume back.
 

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So using analog inputs one would have to use a ddrc24 then analog only into a helix? There is no way to use to toslink in or digital coax hec card? Mini DSP needs to get on that if not.

Also would you use the helix to do remote?
Yea DDRC24 only has analog outputs.

Remote turn on or remote control of the DSP?
 

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One of the advantages of the 8x12DL over using a DDRC inline before another processor is that it can automate this step: It can be set up using a Dirac channel per driver initially to provide precise time delay settings that can then be copied to another 2ch L/R config.
Your correct! Only thing holding me back from 8x12DL and the whole reason for using DDRC22 + Helix is that for my build I need a better control interface like the Helix Director.

I also really want to play around with how Dirac Calibration behaves with a properly up-mixed center channel in the picture (which I plan to do when the DSP Ultra finally comes out).

Probably not the way the algorithm was designed work, but hey can’t hurt to tinker:rolleyes:
 

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What is the ultra? And yes does the helix turn on the mini DSP and amps?
Helix DSP Pro Ultra (aka mk3).

In regards to turning the DDRC24 on. Oabeieo has had success using miniDC from miniDSP which is a DC/DC isolator and remote turn on device. However, it was originally created for the mini DSP 2x4 non HD version. I don’t know if its the higher current draw from the DDRC24 unit, but I tried twice and was unable to get my DDRC24 to turn on via the miniDC and I have very solid 14v+ electrical (perhaps user error with how i was connecting it?). The DDRC24 runs on 12v power and input is a 5 x 2.1mm DC barrel port. No separate + and - terminal and no remote turn on terminal.

I power my DDRC24 with this:
https://www.mouser.com/ProductDetail/mean-well/sd-15a-12/?qs=jVZN1Oke4BzShbKazRd5Vg%3D%3D&countrycode=US&currencycode=USD

And this power supply I have connected to a switched power source that turns on when accessory power is on.

The DDRC22D runs on 5v power and also only has 5 x 2.1mm DC barrel port. Like Oabeieo mentioned, I use a 12v to USB product like:
https://powerwerx.com/usbbuddy-powerpole-usb-converter-device-charger?gclid=Cj0KCQjw5MLrBRClARIsAPG0WGxDGTpAD3n95FflJHDzWFmnVj914DyC_lOCQAr_ui7fUan0xepsYNEaAja5EALw_wcB

Then use a USB to DC barrel cable. The 12v to USB product is also connected to a switched power source.

Maybe more people can chime in with their experiences with the miniDC. If it does indeed power the DDRC24 then one could in theory use the Helix remote to trigger the miniDC.
 

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Discussion Starter #30
Helix DSP Pro Ultra (aka mk3).

In regards to turning the DDRC24 on. Oabeieo has had success using miniDC from miniDSP which is a DC/DC isolator and remote turn on device. However, it was originally created for the mini DSP 2x4 non HD version. I don’t know if its the higher current draw from the DDRC24 unit, but I tried twice and was unable to get my DDRC24 to turn on via the miniDC and I have very solid 14v+ electrical (perhaps user error with how i was connecting it?). The DDRC24 runs on 12v power and input is a 5 x 2.1mm DC barrel port. No separate + and - terminal and no remote turn on terminal.

I power my DDRC24 with this:
https://www.mouser.com/ProductDetail/mean-well/sd-15a-12/?qs=jVZN1Oke4BzShbKazRd5Vg%3D%3D&countrycode=US&currencycode=USD

And this power supply I have connected to a switch power source that turns on when accessory power is on.

The DDRC22D runs on 5v power and also only has 5 x 2.1mm DC barrel port. Like Oabeieo mentioned, I use a 12v to USB product like:
https://powerwerx.com/usbbuddy-powerpole-usb-converter-device-charger?gclid=Cj0KCQjw5MLrBRClARIsAPG0WGxDGTpAD3n95FflJHDzWFmnVj914DyC_lOCQAr_ui7fUan0xepsYNEaAja5EALw_wcB

Then use a USB to DC barrel cable. The 12v to USB product is also connected to a switched power source.

Maybe more people can chime in with their experiences with the miniDC. If it does indeed power the DDRC24 then one could in theory use the Helix remote to trigger the miniDC.
When the 2x4hd was released they had issues with minidsp not supplying enough current. They took it off the item page as recommended for about 6mo and beefed it up a tiny bit (bigger diodes from what I can see I have both) than added back to the HDs accessories.

So yes it can and is. ;-)
 

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I have an isolator from my old mini 2*4 it's older so I bet it doesn't work with the 24
I am leaning towards probably not.

The miniDC units I purchased from miniDSP directly, were purchased ~8 months ago so they should be the ‘beefed’ up versions compatible with the 2x4HD but they it still didn’t power my DDRC24.

I ordered a 2nd one thinking maybe it was a faulty product but still a no go. Then I even tried wiring the 2 miniDC’s in parallel to provide more current but that also didn’t do the trick.

Hence the ~$13 Mean Well power supply from Mouser for DC isolation and using switched power source/relay to trigger it on and off.
 

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how much is too much when doing eq on my system before I put in the DDRC-24? Ive eqd each driver minimally and here is my left right response graphs, Ive separated them by 5 db so they are easier to see. hoping by adding the DDRC-24 before my helix cleans stuff up a bit. Not caring so much on the curve but how it sounds. Of course ill add my sub in the mix first.
 

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You really shouldn't EQ using the Helix. That may end up distorting the phase information that Dirac Live is preserving.

Try this... Use only the Minidsp to do all the EQ correction then use only the Helix to do the crossovers if you're active. LW 24db slope on everything so all the drivers are in phase.

Then if you feel like you have further corrections to make then use the Helix's EQ to do that but turn the EQ bypass on and off on all the drivers to AB. Listen for loss of focus and smearing.


Sent from my iPhone using Tapatalk
 

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You really shouldn't EQ using the Helix. That may end up distorting the phase information that Dirac Live is preserving.

Try this... Use only the Minidsp to do all the EQ correction then use only the Helix to do the crossovers if you're active. LW 24db slope on everything so all the drivers are in phase.

Then if you feel like you have further corrections to make then use the Helix's EQ to do that but turn the EQ bypass on and off on all the drivers to AB. Listen for loss of focus and smearing.


Sent from my iPhone using Tapatalk
If I just set electrical crossovers they are really far off. My mid electrically crossed at 350 to 3000 ends up being around 250 to 3200 acoustically. Even if I cross them at something that helps me get close to a good acoustical crossover they are still way off. Miles off. Do I just use eq on the Helix only in the crossover regions?
 

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Discussion Starter #39
Have you tried specifically with a DDRC24? I know it is literally the same hardware as 2x4HD but the firmware upgrade apparently causes it to draw even more current than the 2x4HD:
https://www.minidsp.com/forum/hardware-support/14275-ddrc24-not-work-with-minidc-isolator
Have one running one now as we speak . No issues

I have the ddrc24 and two HDs and a ddrc22d

All of them I have there own dedicated minidc no issues no noise
Works great!

It draws such little power.

The ddrc24 and the 2x4hds when operating get warm, pretty warm almost hot but just warm. That’s normal and they all seem to get the same temp.
 

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Discussion Starter #40
how much is too much when doing eq on my system before I put in the DDRC-24? Ive eqd each driver minimally and here is my left right response graphs, Ive separated them by 5 db so they are easier to see. hoping by adding the DDRC-24 before my helix cleans stuff up a bit. Not caring so much on the curve but how it sounds. Of course ill add my sub in the mix first.


You don’t need much

If you have a peak in a stop band , knock it down before DLC
That’s about it. Do tape measure distance on TA before DLC
And if two speakers are within 5” of taps measure distance I usually settle on the the halfway for both , you’ll get better crossover behavior after Dirac in some instances that way.

Meaning. If RF tweeter is 50” and the RF mid is 54” set both to 52.5” .
For example. And this trick is really a big deal on lower frequencies, to a tweeter it may not be a issue but a mid to midbass it would be huge.


What happens at crossover in low frequency is the wavelength is much larger than the distance between the two drivers, have odd delays can cause cancellations in the stop band (crossover interaction area where critical blending occurs ) and Dirac when it moved the sum of the phase if there not playing as one speaker , one will have cancellations in the crossover region.


But really, that’s about it. That and some trial and auditions of diffrent eq on drivers crossover regions so the after DLC has both at levels that compliment your stage.

That meaning: do the DLC and listen , if the mid to tweet sounds like one is playing louder than the other or you intentionally want one to play louder you can eq down the other beforehand and can help shape the stage

After DLCT, don’t use manual TA or manual EQ on low frequencies, it messes with the ambiance and the correction all together
The after should only need maybe some level adjustments like maybe turn left down a little to get the center stronger and good balance between left and right


Changing a little bit of levels won’t hurt much
 
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