REW: Disk vs line input to DSP

[Cutaway]

I searched thru the forum but was not able to find what i was looking for.

1. Is there a general preference between using a CD as a pink noise source OR is it better to use the headphone out of the laptop (or USB adapter for the mic) and plug directly into the dsp? Unfortunately, my head unit only accepts CD, USB or Bluetooth connections for media.
2. What will i gain by using REW as the sound/signal source vs CD Pink Noise?
3. I think by not using REW i miss out on the ability to use Sweeps, but does that mean i am missing overall functionality in the tuning process
4. Lastly, is the whole REW vs CD more of a "6 vs 1/2 dozen" type situation?

Sorry for such n00b questions but sometimes while i am reading thru old posts or REW FAQ's i tend to over question or over analyze and i need to do a sanity check with others

[dumdum]

I much prefer to use the same source for pink noise as the primary Source I will use the most, in my case I will use pink noise from my iPhone for equalisation as I use that for tidal and also alac playback, so it makes sense to use its output for tuning

[preston]

Yeah if you can use wav files on the usb or a CD, by plugging directly into the DSP you are bypasing the head unit entirely and therefore not tuning around whatever limitations it might have. I assume you don't have a digital out on the head unit ? that means the signal is going through a DA conversion and being sent to the DSP analog input ? So again if you plug into the DSP you bypass all of this in your tune. Now, on paper, it shouldn't really matter, the sonic signature from the head unit should be pure, but in the real world it doesn't make sense to me to tune while bypassing your primary source ! Its a bit more of a pain to use tracks rather than the REW signal generator and I believe it would limit you from some of the more advanced operations including sweeps and automated testing. For fun you could save a pink noise from CD measurement and then record the same measurement from the jack plugged directly into the DSP. In fact I dn't htink you'd see a huge difference, but I would still try to use the head unit as much as possible.

[Jdunk54nl]

You can always save to file a sweep and Periodic PN, then transfer that to a USB.

I like Pink Periodic pink noise.

To do a sweep you then hit measure on REW, then hit play on the file. There should be a timing reference in the file that tells it a sweep is about to begin. REW will "Wait to start measurement" until this happens.

I actually save them to my phone and play them from that via usb.

If you do not use files from REW, make sure you use correlated pink noise, playing individual speakers it doesn't matter, but playing speaker pairs will need correlated to see where your center is at.

[ckirocz28]

You can always save to file a sweep and Periodic PN, then transfer that to a USB.

I like Pink Periodic pink noise.

To do a sweep you then hit measure on REW, then hit play on the file. There should be a timing reference in the file that tells it a sweep is about to begin. REW will "Wait to start measurement" until this happens.

I actually save them to my phone and play them from that via usb.

If you do not use files from REW, make sure you use correlated pink noise, playing individual speakers it doesn't matter, but playing speaker pairs will need correlated to see where your center is at.

What he said.^^

[Cutaway]

Thanks for everyone's feedback, it's much appreciated!! Just for clarification, Im taking it that there really isn't a preference between using REW's built in sweeps vs external Pink Noise..

[Jdunk54nl]

Thanks for everyone's feedback, it's much appreciated!! Just for clarification, Im taking it that there really isn't a preference between using REW's built in sweeps vs external Pink Noise..

REW with periodic pink noise that you know the FFT for is the best option for pink noise. It doesn't really matter where it came from, just set the settings in REW appropriately.

Here is a 11 minute 64k FFT Pink PN generated from REW file
Make sure to set the FFT length in REW's RTA screen for 64k.