I prefer single-driver speakers.
An old engineer once said,"The fewer holes you poke in your boat, the less bailing you have to do." :^)
An old engineer once said,"The fewer holes you poke in your boat, the less bailing you have to do." :^)
Time alignment, important? long
Sound wave certainly does not travel at the same speed for all frequencies, but music recording and reproduction often neglect this fact. Take recording for example, distance of a microphone will have strong effect on how the sound will emerge and be recorded. Say standing one meter from a jazz band vs. 5 meters from the band, you do expect bass to show up slightly slower when standing further from the band much like lightening appears much earlier than thunder. Since not too many recording is done with single microphone, the recording engineer further complicates this result.
One group of speaker designers stresses this issue by “time align” the drivers, this is usually done by tilting the face back (Thiel, Meadowlark) or move the higher freq drivers back in vertical plane (Dunlavy, Vandersteen). Consider a speaker driver generates a range of frequency, moving the higher freq drivers back in vertical plane does NOT align in time domain since 3000 Hz sound will still arrive at your ear earlier than 100 Hz which is generated by the same midrange driver. So that leaves tilting the face as the only viable solution to correctly time align drivers. However, how many speakers actually have identical tilt angle? In theory, delay vs. freq should be a constant value and all speakers that claim to be time aligned SHOULD have the same tilt angle.
Now come the bigger questions. I hear people praising Merlin, Dynaudio, and Maggie constantly, I have first hand experience with most of them and could not agree more, but none of them is time aligned! Music recording is not done in time align fashion whether single or multi microphones are used. On top, every instrument generates not one single freq, but a range of freq, so microphone actually is receiving the sound with time delay in all instances.
Is that a coincidence the aforementioned brands are well received because they PURPOSELY do not time align their speakers to properly reproduce the time difference captured by recording or they sound great because of other factors? Will they sound better if they were tilted back at an exact angle to time align the drivers? If so, why haven’t any owner done that. Or better yet, why haven’t the manufactures done that?
What's your take on this time alignment theory?
One group of speaker designers stresses this issue by “time align” the drivers, this is usually done by tilting the face back (Thiel, Meadowlark) or move the higher freq drivers back in vertical plane (Dunlavy, Vandersteen). Consider a speaker driver generates a range of frequency, moving the higher freq drivers back in vertical plane does NOT align in time domain since 3000 Hz sound will still arrive at your ear earlier than 100 Hz which is generated by the same midrange driver. So that leaves tilting the face as the only viable solution to correctly time align drivers. However, how many speakers actually have identical tilt angle? In theory, delay vs. freq should be a constant value and all speakers that claim to be time aligned SHOULD have the same tilt angle.
Now come the bigger questions. I hear people praising Merlin, Dynaudio, and Maggie constantly, I have first hand experience with most of them and could not agree more, but none of them is time aligned! Music recording is not done in time align fashion whether single or multi microphones are used. On top, every instrument generates not one single freq, but a range of freq, so microphone actually is receiving the sound with time delay in all instances.
Is that a coincidence the aforementioned brands are well received because they PURPOSELY do not time align their speakers to properly reproduce the time difference captured by recording or they sound great because of other factors? Will they sound better if they were tilted back at an exact angle to time align the drivers? If so, why haven’t any owner done that. Or better yet, why haven’t the manufactures done that?
What's your take on this time alignment theory?
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- 14 posts total
Duke (Audio"movement") covered lots of ground. Yes, tilting the mid-tweet baffle (which unfortunately means that the drivers fire at the ceiling) is a way of geometrically aligning the drivers so the pathlength from their reference point to our ears is the same. I don't know if the woofer presents much of a problem if it enters @~200 or lower; wavelengths are longer there and our ears weaker... so, a few mm difference would not be AS critical vs the wavelength as, say, at 3kHz (lambda=~11 cm). I would try to be more careful in the critical region 300-5kHz where our ear is most sensitive. Maybe that's the region Dynaudio was worried about? {However, geometrical alignment isn't enough for a linear phase system; the crossover also plays its ugly role and, as Duke notes, a good contender here could be a first order Butterworth...} OTOH, with drivers on the same plane one can achieve flat AMPLITUDE response -- maybe what the designers of such speakers intended in the first place?? |
Well, I really dug back into this Audiogon forum to extract this thread for you (somebody last posted on 9/9/03!). Do yourself a favour & read this thread. Somewhere in the middle Roy Johnson of Green Mountain Audio pipes in & gives us some incredibly good info on this subject. Every bit worth reading to educate yourself. http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1032037028&read&3&4& Hope that this helps. |
- 14 posts total