Quote:
Originally Posted by rlacoste
Is that it? A sneer at Dickason work, a smiley and a dismissal of the audibility of higher GD?? Any real merits, other than your “opinion”? You know, like references, more worthy perhaps, to point to us commoners (with names, page numbers, links etc...)
I am disappointed Wayne, I was hoping you can do a bit better than that…
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Au contraire , it's you who has dismissed what i have said...
Ohhh, i can do a lot better , where do you want to go with this, I'm also aware what we are discussing is not covered in Dickason's book, yet you are hanging on to your GD axiom .
Interesting topic by Dickason , the part about VB optimized drivers usually having less mass, I'm sure you are aware of what mass does to the signal, yet you are willing to trade one advantage for another and still call it the best, sadly you are holding on to one part of a very complex puzzle , so i guess you believe everyone else doing VB must have not read Dickason's book........
IMO GD advantages you are claiming amounts to nothing in the overall picture, when venting the cabinet towards the rear wall really helps to eliminate most of the nastiness associated with VB.
Your GD assertions,
Group delay being a measure of the time delay of a waveform amplitude through a speaker , amplifier or cd player is no different as it relates to speakers, As to VB vs Sealed , the GD function of both are very similar until Port resonance and coupling..
Unfortunately sealed enclosures also radiate low frequency, not only from the front, but from the rear and sides too. This signal bouncing off the front wall
( speaker rear) and adding to the ambient character and boundary reinforcement of the speaker is delayed to the original signal, same as firing the ports to the rear, this does not technically eliminate GD as present in a VB, but what it does is add this character to the already delayed reverberant field of the original signal in the room, the delay is not at all obvious from the listening position, if front firing i will agree, this is an issue and no likey ....
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Any advantages you think you had has been reduced to naught....
Since all frequency components of a signal are delayed when passed through a device such as a loudspeaker and propagating through a medium, such as air, this signal delay will be different for the various frequencies unless the device has the property of being linear phase.
Linear phase should not be confused with minimum phase, is the Q7 linear phase ? time constant ...?
So unless this is so , tells me that any signal consisting of multiple frequency components will suffer distortion because these components are not delayed by the same amount of time at the output of the device.
Less take a look at the Q5 step response as tested by stereophile, it's far from being linear phase, each and every speaker has it's advantages and disadvantages , it's the sum of it's strengths that adds up to good audio , the Magico measures well, take nothing away from that , aside, I do not see nor hear this technical advantages to sealed over VB as presented by you, I see each presenting a different set of strength and weakness's .
Regards...
PS: looks like i cant post pics , so a link will have to do ....
Magico Q5 loudspeaker Measurements | Stereophile.com
DB Keele
http://www.xlrtechs.com/dbkeele.com/papers.htm