finkaudio
pfm Member
....without starting the whole discussion again, I just want to add what happened to me yesterday/today and showed me how good our ear/brain works.
I was tuning a car sound system for the last weeks. Two woofers/tweeters in the front, a full range on the back seats. Tuning is done via a DSP in the head unit with 7 BiQuads (EQ) and a delay between the 4 amp channels.
With the EQ one can remove the nasty 100/250 modes you normally have in the cabin and the bass level plus some other small issues.
The rear speakers are delayed by a few mS, so they "disappear" from the front passengers and also bring the image forward for the listeners on the back seats.
Yesterday I drove with the car to the customer and had many hours of time to listen. Was OK for far, but not the timing. Not really bad, but also not spot on. During the drive, I stopped from time to time to do small adjustments in order to improve timing. No success. At the end, I started to make small changes on the delay between the front and the back speakers and suddenly, the whole thing came together. And what was the difference between OK and spot on? 0.2mS
. That's it. I did an experiment when I arrived and ask people to listen between the two settings (tuning tools allows very easy A/B comparisons). Everybody with some experience in listening spotted the difference and we had 100% correct results. Two people (with almost no experience) heard nothing......even so we tried to explain what it was.
Of course you can measure the 0.2ms on impulse response if you try hard but it would not make ANY difference on the response together with all the reflections coming in already very early.
It's amazing that our brain obviously can very well differentiate in the time domain and cares about very small differences - somebody, who just measures the response or the "general" impulse response" could argue, the 0.2mS cannot be relevant. But they are, as I experienced (again) yesterday.......
I was tuning a car sound system for the last weeks. Two woofers/tweeters in the front, a full range on the back seats. Tuning is done via a DSP in the head unit with 7 BiQuads (EQ) and a delay between the 4 amp channels.
With the EQ one can remove the nasty 100/250 modes you normally have in the cabin and the bass level plus some other small issues.
The rear speakers are delayed by a few mS, so they "disappear" from the front passengers and also bring the image forward for the listeners on the back seats.
Yesterday I drove with the car to the customer and had many hours of time to listen. Was OK for far, but not the timing. Not really bad, but also not spot on. During the drive, I stopped from time to time to do small adjustments in order to improve timing. No success. At the end, I started to make small changes on the delay between the front and the back speakers and suddenly, the whole thing came together. And what was the difference between OK and spot on? 0.2mS
. That's it. I did an experiment when I arrived and ask people to listen between the two settings (tuning tools allows very easy A/B comparisons). Everybody with some experience in listening spotted the difference and we had 100% correct results. Two people (with almost no experience) heard nothing......even so we tried to explain what it was.Of course you can measure the 0.2ms on impulse response if you try hard but it would not make ANY difference on the response together with all the reflections coming in already very early.
It's amazing that our brain obviously can very well differentiate in the time domain and cares about very small differences - somebody, who just measures the response or the "general" impulse response" could argue, the 0.2mS cannot be relevant. But they are, as I experienced (again) yesterday.......
