OK, let's reincarnate the thread.
The question is: is alignment important at, say, 8-9KHz cut point? If I remeber well, psyphoacoustics says at such frequencies we don't detect phase. Instead, we detect sound energy. This is a reason why alignment can be not so important at such case. Has anybody experience here?
The question is: is alignment important at, say, 8-9KHz cut point? If I remeber well, psyphoacoustics says at such frequencies we don't detect phase. Instead, we detect sound energy. This is a reason why alignment can be not so important at such case. Has anybody experience here?
anli said:
Well, if the pathway from the two drivers differ by half a wavelength, the total amplitude will be zero. So even if the ear cannot detect the phase difference between the two, if can detect that the amplitude is zero.
On the other hand, crossing over at such a high frequency as 9 kHz will result in a directivity pattern that has a very high number of lobes, and it might be that the lobes occur so closely that it is actually better than the one or two large lobes that frequencly occur at lower crossover frequencies.
An externally hosted image should be here but it was not working when we last tested it.
anli said:
Very difficult to hear the difference because it is very unlikely that your ears are on the exact design point. There is a measureable difference at the design point and as you shiff off design point. Purcussion transients you probably can hear very slight differences, however, you will not notice it unless you really try to detect it.
If the super tweeter that you are using is not well damped, you probably can;t hear the difference at all.
Just this case takes place. Measurements at listening point show I must move a supertweeter about 1.5-2cm toward to listener, but I can not hear any differences hearing real music (say, spatial effects in "Amused To Death" by Roger Waters). A supertweeter (CP21F by Beyma in my case) is connected via serial R=8R2 and C=1uF.soongsc said:
Thanks, I'll sleep well
soongsc said:
My point is that it isn't that bad with a pattern like this. Many lobes close to one another might be much better than few and large lobes, in particular in a room.
But you are right in that the patterns of the individual drivers will affect the total pattern too. Yet again there will always be at least one frequency in any direction where the drivers play equally loud, and at that frequency there is potential for either constructive or destructive interference.
So, my diagram that showed the directivity at the crossover frequency for two ideal point sources sort of applies anyway, it is just that also the frequency would vary with the angle. Of course this would not be a nice way to present real data, but conceptually I think is has a point.
Svante said:
My point is that it isn't that bad with a pattern like this. Many lobes close to one another might be much better than few and large lobes, in particular in a room.
But you are right in that the patterns of the individual drivers will affect the total pattern too. Yet again there will always be at least one frequency in any direction where the drivers play equally loud, and at that frequency there is potential for either constructive or destructive interference.
So, my diagram that showed the directivity at the crossover frequency for two ideal point sources sort of applies anyway, it is just that also the frequency would vary with the angle. Of course this would not be a nice way to present real data, but conceptually I think is has a point.
Yes. This tool does give a good demonstration what to look out for during design.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.