Foxenfurter
Active Member
Can more experienced members please advise on acceptable ways to level match 2 sources prior to posting DBT test results. I am looking for the simplest/easiest/cheapest and least risk approach for a newbie to follow.
Sources were asked for, other than phono is the process not the same for everything else?For starters we would need to know what you want to DBT.
Files, DAC's, Amps, cables, speakers ?
I just went through this and made some home made attenuators out of a 20 K ohm 12 turn potentiometer and some old RCA cable ends ... these are easy and accurate to adjust and they don't change once set. I think you can buy something like this but if you can solder the parts are only a few dollars. I then used REW (free software) to generate a 500 Hz signal to send to the speaker and used the attenuator on the higher gain (louder) device to match the voltage levels between the devices. Good luck and I think you will find it worth the trouble.Can more experienced members please advise on acceptable ways to level match 2 sources prior to posting DBT test results. I am looking for the simplest/easiest/cheapest and least risk approach for a newbie to follow.
Note that you don't need an accurate or a true RMS meter. The meter's error will be the same for both readings.Measure voltage. Measuring with a sound level meter isn't close enough for DBT.
Measure voltage out DACs, and at speaker terminals. If you have a way of matching them the one that matters is at the speaker terminals.
You need both sources within .1 db of each other optimally. That would be a difference between voltages of 1.2% or less.
So if one source is 1.00 volts the other should be between 1.012 volts and .988 volts.
Okay, do you run a separate preamp? You can mark or use the volume control or rather have someone do it for you.Yes, that was going to be next question about how to fine tune the levels to ensure they match, I had been trying to do it by ear, but was not convinced I had it right so gave up. I don't have the time or ability to add an attenuator, and even then there would be complaints from some parties that this itself is colouring the sound. So it seems like there is quite a high barrier to entry for making meaningful listening comparisons between audio sources, which also explains why we end up either having measurements or impressions and it is so difficult to reconcile the objective and subjective worlds.
I only see that as an issue if you get an identifiable difference that is surprising, if you cannot detect a difference it does not really matter.I don't have the time or ability to add an attenuator, and even then there would be complaints from some parties that this itself is colouring the sound.