Measurement problem

[Nemanja]

Good evening gentlemen,
I have a problem with the measurement so please help. I can't use the hdmi cable because I have a macbook air, and Naim uniti Nova (which doesn't use the hdmi connection except to communicate with the tv). So I am forced to connect rew ie. macbook via airplay. In this way, I get unusual measurement results, which I send below.

 

[John Mulcahy]

There can be a lot of latency with Airplay, which can cause the end of the sweep not to be captured. To cope with that use the acoustic timing reference.

 

[Nemanja]

Thanks John, but how do I determine the references

 

[John Mulcahy]

I don't understand your question, sorry. To use the acoustic timing reference select that option on the Measure dialog and make sure the timing reference output channel selected is one that is connected to a speaker that has a tweeter, because the timing signal is a high frequency sweep.

 

[Nemanja]

Ok, there is two options: use loopback timing reference (and time offset: some number) and
use acoustic timing reference (timing offset: some value, and ref level trim: x db)

 

[John Mulcahy]

As above, use the acoustic timing reference. You don't need to set up a timing offset or a level trim.

 

[Nemanja]

Thanks a lot, John. A new measurement is attached. How do you feel about this measurement and should I do something about adjusting the equalizer within the rew or maybe moving the speakers, room acoustics, ...

 

[John Mulcahy]

Best to experiment with speaker and/or listener position as a first step, assuming you have some flexibility in positioning. A quick way to do that is to play the Pink Periodic Noise (PN) signal and watch the response on the RTA while you move things. Here are some suitable RTA settings to use:

 

[thumprchgo]

Good evening gentlemen,
I have a problem with the measurement so please help. I can't use the hdmi cable because I have a macbook air, and Naim uniti Nova (which doesn't use the hdmi connection except to communicate with the tv). So I am forced to connect rew ie. macbook via airplay. In this way, I get unusual measurement results, which I send below. View attachment 37602

You don't mention the version of the Air model you have. If you have either a mini DisplayPort or Thunderbolt port you can get an adapter to connect Mac audio to your amp with an HDMI cable. Failing that, you can use a USB-Optical adapter to connect a "Toslink" digital audio cable to your amp. Either would be an improvement not only in audio latency, but also audio quality. The Audio/MIDI Setup app that comes with all macOS computers -- in the Utilities folder inside the Applications folder-- will help you set it up. Apple, Amazon, and Newegg have these mini DP adapters for about 15-20 dollars US.

You can search "connect HDMI to Macbook Air" for a link a link to Apple Support that can help explain.

 

[Nemanja]

I have a Thunderbolt to HDMI Adapter. The problem is that my amplifier Naim uniti Nova (all in one device) can't use hdmi as input (it only uses to connect tv via arc hdmi).
I have both optical and coaxial inputs on the amplifier, as well as rca but I can't use it to connect to a macbook air 2013 late