Struggling to set levels correctly

[ChrisOH2001]

Hi all

I’m a relatively new user of REW and am having difficulty with my Levels so am here to see if someone can point me in the right direction please.

I use a Umik 1 90 degree cal file installed, Pink Random noise to set my Trinnov Amethyst output until l reach the 75dB target. When I check levels in the measurement tab it reports “Levels Low 45dB (-78dBFS). No sound plays when I use the check levels function.

If I check levels in the preferences tab I get sound. The Levels show Output hovering around -12 and Input and reference input at circa -41.

I have checked the Mic settings in Windows and it is set to 52 (or 0dB)

I’m scratching my head after watching and reading a lot of guides as I can’t put my finger on what is going wrong.

I am able to take measurements but they are sometimes failing and reporting high distortion as there is too much gain somewhere which I’m also struggling with

Apologies for the rambled explanation, any advice gratefully received

 

[John Mulcahy]

Can you post screenshots of your REW soundcard preferences and the Measure dialog?

 

[ChrisOH2001]

Hello John,

Thanks for your reply and the awesome software. Since I posted I have now got the levels working albeit, I have no idea how :-). The issue I still face is that in any given set of measurements, I find that a significant portion fail as the sweep only becomes audible part way through so part of the measurement is not there. I'm using a UMIK-1 and its cal file and as I understand it I do not need a timing reference although I have tried using the Acoustic reference which again I understand is the only one i need with the UMIK.

I'm persevering and making some good progress and thanks again for the amazing software.

Chris

 

[John Mulcahy]

I find that a significant portion fail as the sweep only becomes audible part way through so part of the measurement is not there.

Sounds like there is a substantial latency in the replay path somewhere. The acoustic timing reference should deal with that if the issue is latency. Another possibility is that the replay chain is slow to unmute when a signal is received, which may be helped by choosing the "Play dither before sweep" option on the Measure dialog.

 

[ChrisOH2001]

Many thanks again John,

That's where i got to as for sure there is latency to deal with as I'm running through HDMI from my laptop dock into a Pioneer media box which is outputting via RCA (digital not currently working) to a Trinnov Amethyst. The Trinnov is doing 2.2 and I am trying to add another two subs so i have a 2.4 system which is where the miniDSP and REW come in. The Trinnov has no HDMI nor USB inputs hence having to go through the TV media box. I have another pre but it is anallogue and i only have HDMI out from my PC dock

As an alternative I was trying to use the miniDSP on the two LFE outputs from the Trinnov outputting to two pairs of subs. Plan was to time align and EQ the two pairs and then present them to the Trinnov for RC. Got some weird results so back to plan A for now.

I did try the play dither thing but it didn't seem to help. That said, it won't hurt to try again

Thanks for your help

Chris

 

[ChrisOH2001]

Hello again,

I’m still struggling for some silly reason no doubt as I have had REW working previously via the same set up (media box>Trinnov)

Levels report as OK 41.7dBFS and 56dB SPL

I have volume matched all 4 subs

I’m using play dither before sweep and I’ve tried a range of different sweep lengths

At 64k REW gets to 17% and holds waiting for the timing reference

At 128k it gets to 11%

Neither of these sweep lengths result in an audible sweep playing.

At 256k it gets to 7% and then a few seconds later a sweep is heard but REW is still waiting for the timing reference

At 512k it gets to 4% and again a few seconds later a sweep is heard while REW is still waiting for the timing reference.

Although a sweep can be heard and seen on the input trace a measurement is not recorded.

I’ve stopped using the timing reference and am now using 512k sweeps which have a higher success rate.

Made a number of measurements for each individual sub and pairs of subs as well as all four together.

The measurements include both t=o at IR peak as well as at IR start

My plan was to treat the front pair as fixed and the use REW to add the two rear subs as an EQ’s pair but I can’t figure out why I need so much delay on the rear pair. When I hit play on the Master volume to set levels using the SPL meter, there is a 4 second delay before the test tone kicks in. This is broadly the same whether it is the front subs through the media box into the Trinnov or through the media box into the miniDSP for the rear subs.

I’m attaching the mdat as a start if someone could have a quick look and tell me whether the measurements are of any use to start with (I was getting distortion reports)

Thanks in advance for any input.

Screenshot 2024-01-13 144424

Screenshot 2024-01-13 144157

 

[ddude003]

Looking at a user manual for the Trinnov there appears to be a Wifi and Ethernet connection that maybe a music player app can send a REW Generated sweep tone to the Trinnov... Use the REW Generator function to create a .WAV sweep file with a timing ref... This is how I measure my complete signal path through my system... Are there 4 USBs on the back? If so you could save that .WAV file to a USB jump stick and play directly from the Trinnov? Looking at rear panel section 2.3 Power section...

You might also add a few dB to the Ref level trim...

 

[ChrisOH2001]

Cheers ddude, I'll have a look into the suggestion, although if the fikle was playing from the Trinnov then it would not get to my miniDSP i think as it is connected to an LFE out from the media box. Signal goes from my laptop to the media box then to both the Trinnov (RCA in) and the miniDSP (via LFE out RCA)

 

[ChrisOH2001]

Just found this page in the Trinnov which states an In/Out delay of 188.6ms. If this is the same as the delay from mini DSP then I'm on a hiding to nothing it seems

Screenshot 2024-01-13 202650 bn[/url],

 

[John Mulcahy]

The timing reference output needs to go to a speaker with a tweeter.

 

[ChrisOH2001]

Thanks Jonn, that clears that up then as I'm measuring subs of course