Can I utilise any of this equipment to elimate my sound card from REW measurements system ?

mamba76

New Member
Thread Starter
Joined
Sep 9, 2017
Messages
38
Location
SE London
My AV System  
Preamp, Processor or Receiver
Lenovo M8 FHD tablet
Main Amp
JL Audio XD600/6 (front end)
Additional Amp
JL Audio XD400/4 (midbass)
Other Amp
JL Audio XD1000/1 (sub)
Front Speakers
Focal Utopia (2003 model) (6W2's + TN51's)
Surround Back Speakers
JL Audio ZR800s (pair)
Subwoofers
JL Audio 13W3 4ohm
Streaming Equipment
miniDSP 2x4HD feeding C-DSP6x8
Iv been using the same setup with a miditech2 external soundcard for years now but Im just reproaching things after a couple years away from my CAR audio system. I cant remember but is the loopback connection needed for relative time alignment ? After all aligning the drivers between themsleves is whats important so why / when would you need absolute timing ?
Im trying to simplify my measurement systems. I now have 2 minidsp 2x4HDs being fed by a minidsp USBstreamer. Can I not eliminate my miditech soundcard somehow with all the equipment I have now ?
Heres a rushed sketch of my system ATM.

Im just trying to streamline the system and maybe get rid of the analog connections.
Thanks
51694
 

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
5,436
You need a timing reference to allow timing to be compared between different measurements. In a car a loopback is the most reliable, the acoustic timing reference is less reliable in such a highly reflective environment. With the loopback and the analog mic you need the soundcard.
 

mamba76

New Member
Thread Starter
Joined
Sep 9, 2017
Messages
38
Location
SE London
My AV System  
Preamp, Processor or Receiver
Lenovo M8 FHD tablet
Main Amp
JL Audio XD600/6 (front end)
Additional Amp
JL Audio XD400/4 (midbass)
Other Amp
JL Audio XD1000/1 (sub)
Front Speakers
Focal Utopia (2003 model) (6W2's + TN51's)
Surround Back Speakers
JL Audio ZR800s (pair)
Subwoofers
JL Audio 13W3 4ohm
Streaming Equipment
miniDSP 2x4HD feeding C-DSP6x8
Thanks John I realise that now, I originally wanted an optical out to the minidsp but then it would need to be converted to digital, pretty pointless as the DSP does the same, Ill just upgrade the analog connection. I wondered if I could use two beringer mics with my miditech 2 channel soundcard, I beleive these would be muxed together? Maybe one in driver position and one in passenger which may yeild better results overall, but isn't the second channel occupied by the loopback ?

I should rephrase the yield better results part, I mean do you think using multiple mics would represent a more accurate measurement to work with ?
 
Last edited:

mamba76

New Member
Thread Starter
Joined
Sep 9, 2017
Messages
38
Location
SE London
My AV System  
Preamp, Processor or Receiver
Lenovo M8 FHD tablet
Main Amp
JL Audio XD600/6 (front end)
Additional Amp
JL Audio XD400/4 (midbass)
Other Amp
JL Audio XD1000/1 (sub)
Front Speakers
Focal Utopia (2003 model) (6W2's + TN51's)
Surround Back Speakers
JL Audio ZR800s (pair)
Subwoofers
JL Audio 13W3 4ohm
Streaming Equipment
miniDSP 2x4HD feeding C-DSP6x8
oh cool, I didn't know there was a pro version!
On the back of that, not my intention, but I'v noticed a problem with my impulse signals/tab. When I adjust the delay on my pair of MiniDSP2x4s sometimes it iis not reflected in the measurement, the wave will exactly match precious sweeps even tho the delay has changed, more than half a millisecond in some cases. I never noticed this in previous versions but then also Iv just switched to the 2x4HD as was using the CDSP6x8. My sound card is 48khz, these DSPs operate at 96Khz I believe ? Thanks
I use windows 10 64bit
This could be a plugin issue as they are unfortunately my pet hate and I strongly believe MiniDSP would benefit hugely from a new / modern interface.
 
Last edited:

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
5,436
Best way to check the behaviour of the DSP is to measure the line outputs directly, excluding the driver and mic.
 

mamba76

New Member
Thread Starter
Joined
Sep 9, 2017
Messages
38
Location
SE London
My AV System  
Preamp, Processor or Receiver
Lenovo M8 FHD tablet
Main Amp
JL Audio XD600/6 (front end)
Additional Amp
JL Audio XD400/4 (midbass)
Other Amp
JL Audio XD1000/1 (sub)
Front Speakers
Focal Utopia (2003 model) (6W2's + TN51's)
Surround Back Speakers
JL Audio ZR800s (pair)
Subwoofers
JL Audio 13W3 4ohm
Streaming Equipment
miniDSP 2x4HD feeding C-DSP6x8
Will look into it, thanks
 
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