My buddy BJ (Premier Cabinets) was looking for something to do so he pulled out his slowing decaying SpeakerLab System 7 speakers that have been sitting idle for years and decided to rebuild them. He' not an avid speaker builder but is pretty good building cabinets. Below is a link to some pictures I took of the dismantled speakers. If anyone has any tips or comments please feel free. Thanks.
http://www.alegriaaudio.com/BJ's%20System7_Rebuild.htm
http://www.alegriaaudio.com/BJ's%20System7_Rebuild.htm
sreten-
Ok, to make sure I understand, you're saying the drivers should all be on the same vertical axis?
Another interesting problem is that the motor on the tweeter has a larger diameter than the horn. The previous solution was to cut a large enough hole for the motor to pass through, then use popsicle sticks to fill the gap around the horn. Nobody cared because there was always a grill cover on it. Is there a better solution?
Also, BJ accidently poked a hole in the mid-woofer with a nail when he was taking the speaker apart. What's the easiest way to repair this? The hole is very small.
Ok, to make sure I understand, you're saying the drivers should all be on the same vertical axis?
Another interesting problem is that the motor on the tweeter has a larger diameter than the horn. The previous solution was to cut a large enough hole for the motor to pass through, then use popsicle sticks to fill the gap around the horn. Nobody cared because there was always a grill cover on it. Is there a better solution?
Also, BJ accidently poked a hole in the mid-woofer with a nail when he was taking the speaker apart. What's the easiest way to repair this? The hole is very small.
Yes they should be vertically aligned, at least the T,M and
10", the midrange obviously turned through 90 degrees.
The tweeter :
I think you mean the motor diameter is wider than the horn width.
It may go in the normal hole if you remove the motor, fit the horn
by angling it through the hole and refitting the motor.
I've been thinking about time alignment issues, as the crossover
looks fairly simple. I'd be tempted to fit the tweeter into a small
box that sits on the top, allowing alignment with the midrange.
The hole :
A drop of PVA and push it back into shape from the back.
sreten.
10", the midrange obviously turned through 90 degrees.
The tweeter :
I think you mean the motor diameter is wider than the horn width.
It may go in the normal hole if you remove the motor, fit the horn
by angling it through the hole and refitting the motor.
I've been thinking about time alignment issues, as the crossover
looks fairly simple. I'd be tempted to fit the tweeter into a small
box that sits on the top, allowing alignment with the midrange.
The hole :
A drop of PVA and push it back into shape from the back.
sreten.
Perhaps I'm wrong, but I understood that horns' dispersion is greatest perpendicular to their long axis, so that if you want wide horizontal dispersion the horn ought to be up and down. This is counterintuitive if you think of the horn as sort of spraying out sound, but if you think in terms of diffraction it makes more sense -- the smaller the source the more dispersed the sound. I think that we have all be imprinted by the klipshhorn, which (like most horn systems) orients the horns to fit in manageable (relatively speaking) enclosure, despite acoustic compromises. These compromises may not matter in a room large enough for Khorns, because the listener will be pretty far away, so the sound will be pretty didely dispersed any way, but these speakerlabs look suited for smaller rooms than full size horn systems.
While we are at it, it seems to me that the Altec Voice of the Theater may have had the horn horizontally oriented specifically to disperse sound vertically so as to cover all the seats in a theater with a balcony.
While we are at it, it seems to me that the Altec Voice of the Theater may have had the horn horizontally oriented specifically to disperse sound vertically so as to cover all the seats in a theater with a balcony.
NE,
Sorry but simply not the case.
The outputs of the two horns will gel far better both horizontal.
The only time you'd use a vertical wide horn is in a disco, with
high mounted speakers where the vertical horn gives good
coverage across the dance floor. Domestically a no-no.
The mid horn must be horizontal to give good imaging, I'd expect
this simple change to literally transform the performance of the
speaker for various listening positions, and also give far better
focus for an optimum listening position.
You seem to be applying slot tweeter theory, but this doesn't
work at the wavelengths outputed by a midrange horn.
sreten.
Sorry but simply not the case.
The outputs of the two horns will gel far better both horizontal.
The only time you'd use a vertical wide horn is in a disco, with
high mounted speakers where the vertical horn gives good
coverage across the dance floor. Domestically a no-no.
The mid horn must be horizontal to give good imaging, I'd expect
this simple change to literally transform the performance of the
speaker for various listening positions, and also give far better
focus for an optimum listening position.
You seem to be applying slot tweeter theory, but this doesn't
work at the wavelengths outputed by a midrange horn.
sreten.
I should have taken a picture of the cutout for the tweeter because I don't think I'm describing it well. Once the popsicle sticks are taken off there is enough room to pull the tweeter out. Although, in this case I think most of the cabinet was in pieces first. There's a rectangular cut for the tweeter horn with a larger circle cut in the middle of that so if you're mounting it from the front the motor fits through the circle, then the horn mounts on the rectangular cut, then you put the sticks on to cover the circlular hole because it extends beyond the height of the horn. If you look at the pictures of the tweeter you can almost tell the motor is a larger diameter than the horn.
I know what you're describing, I'm an *old* SpeakerLab fan. That tweeter should be almost identical (in size) to the Electrovoice unit that Klipsch used (uses?). You can usually reach up through the woofer hole and shimmy the tweeter through the tweeter hole from the rear. The Magnet may be too big for the opening, but the rectangular mouth should (err, could) fit through its opening from the rear. Just a thought.
I think the original intent was to mount the drivers from the rear, like in the good old days.
I think the original intent was to mount the drivers from the rear, like in the good old days.
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