REW Testing and USB cable lengths

[Coylum]

I am new to REW and this forum so please bear that in mind! I am using REW to assist in the creation of DSP FIR files in my Eversolo DMP-A8 Network Streamer/DAC within my two channel stereo system.

The convenient location for my laptop, Umik -1 microphone (Input) and Eversolo DMP-A8 (Output) requires a USB cable length of 3M for the microphone to laptop and 8M for the Eversolo DMP-A8 to the laptop. All appears to be working correctly but will these cable lengths have a negative impact on the sound quality and the accuracy of REW?

I can make the connections very much shorter if I position the laptop within the main listening zone i.e. between speakers and listening position but this is not as convenient.

Thank you in advance

 

[skid00]

If there's a problem with cable length, you will get dropouts during the frequency sweep.

I had problems with cables around 5 meters length. It will vary with the quality of the cable.

 

[Coylum]

If there's a problem with cable length, you will get dropouts during the frequency sweep.

I had problems with cables around 5 meters length. It will vary with the quality of the cable.

Thanks - I will watch out for dropouts. I'm just running trials initially to get used to REW so I should know where I stand before doing "real" readings

 

[dcibel]

FWIW USB 2.0 spec is a maximum of 16ft for any cable. Any length longer than that is "at your own risk", there are solutions such as USB repeaters and USB over Ethernet that can allow for very long data transmission. Personally, an XLR mic on 25ft cable is no problem at all.

 

[ddude003]

You can use the REW Generator function to create sweep files (.wav) with a timing ref, you can save to disk and send across a network or put on a jump drive to play over your streamer... Then just play the sweep file through your signal chain and sample from your lappy with the mic... You are no longer depending on a long usb cable between your lappy and your streamer/DAC...

BTY, this is how I do measurements with my kit (full signal chain - Player App, Network, Streamer, DAC, Pre, Amp & Speakers) when creating FIR filters for Digital Room Correction with REW...

 

[sam_adams]

Since you are using two different USB interfaces, the UMIK-1 and the Eversolo DMP-A8, you may run into issues with timing variations between different measurements. See here and here for background info.