Would it be practical to do the following? (just an example)
Mount a 2" Tang Band
onto either a mesh grill, or some form of frame
which would sit over like a 10" or 12" driver?
The tang bands see to be usable down to about 300 or 400Hz, so you could mount them dipole and crossover to the big guy at that point. The HF driver would pretty much sit in the area between the voice coil, since alot of those big LF drivers have 1 1/2" to 2" voice coils. So I guess the main question is would there be any interference caused by the HF driver sitting in front of the LF driver....or the sound waves firing back onto the woofer from the HF driver?
And yes I know I would have to consider woofer excursion too
Would this create a nice point source?
Mount a 2" Tang Band
An externally hosted image should be here but it was not working when we last tested it.
onto either a mesh grill, or some form of frame
An externally hosted image should be here but it was not working when we last tested it.
which would sit over like a 10" or 12" driver?
The tang bands see to be usable down to about 300 or 400Hz, so you could mount them dipole and crossover to the big guy at that point. The HF driver would pretty much sit in the area between the voice coil, since alot of those big LF drivers have 1 1/2" to 2" voice coils. So I guess the main question is would there be any interference caused by the HF driver sitting in front of the LF driver....or the sound waves firing back onto the woofer from the HF driver?
And yes I know I would have to consider woofer excursion too
Would this create a nice point source?
I'm not sure if I fully understand your question, but I do believe that you are trying to create your own type of coaxial speaker. (?) I'll go into detail anyway, I believe what you are trying to do will not work, the sound waves will bounce off the rear of the tweeter and will effectively cancel the sound. If this phenomena may somehow be corrected then, the problem may be a sound quality thing. Try placing a can of some sort in front of a speaker...hands work too, notice the muffled sound...that would be a problem. Though, the human ear is typically more sensitive to sounds from 500Hz.-5,000Hz (I think it's 5,000), your x-over point may avoid this partially. This is just a beginning critique, what do the others think?
A Tangband co-ax. Unique idea!
There would be some concerns regarding the radiation from the rear of the Tangband since you would have room for an enclosure for it - or maybe you would. I don't have the parameters handy.
Of course you'ld have to ask if there are any advantages to co-ax mounting for such a low crossover freq.
Now if you could find and itsy bitsy teeny weeny tweeter to mount co-axially with the Tangband . . . .
There would be some concerns regarding the radiation from the rear of the Tangband since you would have room for an enclosure for it - or maybe you would. I don't have the parameters handy.
Of course you'ld have to ask if there are any advantages to co-ax mounting for such a low crossover freq.
Now if you could find and itsy bitsy teeny weeny tweeter to mount co-axially with the Tangband . . . .
All I say is - just have a look at the following:
http://www.me-geithain.de/en/start_eng.html
Regards
Charles
http://www.me-geithain.de/en/start_eng.html
Regards
Charles
I think the problem with your idea as it stands is not so much that the driver would block sound from the woofer -- at the low crossover you are thinking of, that wouldn't be a problem -- but that the tangband probably needs an enclosure to get that low, and the enclosure would certainly be a problem. Without an enclosure the tangbands backwave would cancel out much of the frontwave, and you would also have the problem of interference with the woofer -- its pressure waves driving the diaphragm of the tangband. If the tangband had a sealed back you wouldn't have these problems, but it also probably wouldn't go down any further than a normal midrange.
I don't have any actual numbers, but isn't it so that if the distance of the midrange from the woofer is less than the wavelength of frequencies being reproduced, that they act as if they are in the same location? I recognise that this requires that the woofer produce no output at frequencies high enough to allow localisation, something that wouldn't be true of normal crossover frequencies unless you used something like infinite slope roll offs, but if you are crossing over at 200 hz, there might be no even theoretical advantage to coaxial mounting. Of course, there are electrical and financial costs to low crossovers...
I don't have any actual numbers, but isn't it so that if the distance of the midrange from the woofer is less than the wavelength of frequencies being reproduced, that they act as if they are in the same location? I recognise that this requires that the woofer produce no output at frequencies high enough to allow localisation, something that wouldn't be true of normal crossover frequencies unless you used something like infinite slope roll offs, but if you are crossing over at 200 hz, there might be no even theoretical advantage to coaxial mounting. Of course, there are electrical and financial costs to low crossovers...
Cool idea...
Another thing to consider is that the tweeter generally needs to be behind the woofer for proper time alignment (think of all the stepped-baffle designs you probably have seen, where the woofer sticks out).
Then again, this could be compensated for with the crossover network, right? Why not give it a try?
I seem to remember crutchfield (and probably others) selling a plasic molded "tray" enclosure for car applications to keep out water, etc. Maybe you could use something like that for the TB, and cross it over well out of the bass range, maybe even as high as 800 hz? Sealed back midranges seem to be able to go that low.
I just don't know that it would be worth doing, especially crossing over at a low frequency, where the wavelengths are so big that the drivers can be a significant distance apart without problems anyway! If you were to use a small tweeter, and cross it over in the midrange area, it may be a better situation. Then you will have to worry about the tweeter effecting the radiation pattern of the midwoofer... may be difficult to do well.
Just some thoughts. Don't let any of the doubters scare you off. Make sure you let us know if something is worth doing!
Another thing to consider is that the tweeter generally needs to be behind the woofer for proper time alignment (think of all the stepped-baffle designs you probably have seen, where the woofer sticks out).
Then again, this could be compensated for with the crossover network, right? Why not give it a try?
I seem to remember crutchfield (and probably others) selling a plasic molded "tray" enclosure for car applications to keep out water, etc. Maybe you could use something like that for the TB, and cross it over well out of the bass range, maybe even as high as 800 hz? Sealed back midranges seem to be able to go that low.
I just don't know that it would be worth doing, especially crossing over at a low frequency, where the wavelengths are so big that the drivers can be a significant distance apart without problems anyway! If you were to use a small tweeter, and cross it over in the midrange area, it may be a better situation. Then you will have to worry about the tweeter effecting the radiation pattern of the midwoofer... may be difficult to do well.
Just some thoughts. Don't let any of the doubters scare you off. Make sure you let us know if something is worth doing!
Although I had the opportunity to look (listen of course as well -and I can say they sound great) at the Geithain Monitor, I didn't watch out for that detail:
But I remember having read some report, where they mentioned that the midrange is mounted onto the small baffle with an open back, only covered with some foam rubber.
Regards
Charles
But I remember having read some report, where they mentioned that the midrange is mounted onto the small baffle with an open back, only covered with some foam rubber.
Regards
Charles
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