Hi all, are the 753 Freedom tweeters compatible with the original Mk1 753 crossover? I have two freedom tweeters that measure 4.8 ohm so assuming they're 4 ohm tweeters. I'll just block off the tweeter holes in the original 753 and run a cable off the crossover from the high section to a tweeter enclosure on top of the 753 box, easily undone if I find the original metal dome rectangular ones! If not, any suggestions for a compatible tweeter? I currently have a centre 753 that I used a 751 tweeter as a replacement, using the high frequency section from a broken 751 box as that's an 8 ohm tweeter, but do I really need to change crossover parts?
Thanks alot!
Thanks alot!
I really have no idea what the differences in crossover between the various Mission 753 models might be. They did seem to fit different 25mm tweeters too.
I would guess this is an 87dB speaker with twin plastic 5" midrange cones, but the 2.5way construction with 4 woofers overall might up that a bit to the claimed 90dB. Hard to say really.
You won't break anything by wiring up a different tweeter, since 4.8 ohms DC is fairly typical of an 8 ohm nominal tweeter.
Something here around 90dB might fit:
Monacor Treble Units
You are interested in the size of the rebate on the baffle, because the tweeter should be flush ideally, and the magnet cutout size (which is easily made bigger, of course).
Because you have a biwireable speaker connection, it would not be hard to add a test series wirewound resistor to reduce treble level before hard soldering the same into the crossover.
Resistors
2.2R might be required for 2dB reduction. Or nothing, if you get lucky.
I would guess this is an 87dB speaker with twin plastic 5" midrange cones, but the 2.5way construction with 4 woofers overall might up that a bit to the claimed 90dB. Hard to say really.
You won't break anything by wiring up a different tweeter, since 4.8 ohms DC is fairly typical of an 8 ohm nominal tweeter.
Something here around 90dB might fit:
Monacor Treble Units
You are interested in the size of the rebate on the baffle, because the tweeter should be flush ideally, and the magnet cutout size (which is easily made bigger, of course).
Because you have a biwireable speaker connection, it would not be hard to add a test series wirewound resistor to reduce treble level before hard soldering the same into the crossover.
Resistors
2.2R might be required for 2dB reduction. Or nothing, if you get lucky.
Attachments
The article is useful as a quick and dirty fix, but I don't like it electrically too much.
The Monacor DT-284S is a 4 ohm tweeter with a 91dB rating at 1W/1m, but in practise that makes it a 94dB tweeter at 4 ohms. Hence the input 2.2R to bring it down about 3dB to about 91dB.
Possibly a better way to attenuate it is to put a 2.2R or 3.3R at the input to the tweeter itself. This will preserve the frequency response for an 8 ohm filter. Avoiding a hole at just above crossover.
What this article is telling me, is that a 91dB 8 ohm nominal is about right with no adjustment to level. The original is apparently a 25mm peerless metal unit, and it's not rebated, so replacement is quite straightforward.
The Monacor DT-284S is a 4 ohm tweeter with a 91dB rating at 1W/1m, but in practise that makes it a 94dB tweeter at 4 ohms. Hence the input 2.2R to bring it down about 3dB to about 91dB.
Possibly a better way to attenuate it is to put a 2.2R or 3.3R at the input to the tweeter itself. This will preserve the frequency response for an 8 ohm filter. Avoiding a hole at just above crossover.
What this article is telling me, is that a 91dB 8 ohm nominal is about right with no adjustment to level. The original is apparently a 25mm peerless metal unit, and it's not rebated, so replacement is quite straightforward.
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