Tweeter wiring

[Protium]

How do
If I want to wire up an 8ohm tweeter with an 8ohm woofer do I need a full crossover or can I get away with just using a high pass filter @ 4kHz on the tweeter?
Cheers

[rslaing]

[quote name='Protium' post='526297' date='Jun 27 2009, 09:39 PM']How do
If I want to wire up an 8ohm tweeter with an 8ohm woofer do I need a full crossover or can I get away with just using a high pass filter @ 4kHz on the tweeter?
Cheers[/quote]

Ask Alex Claber - he knows everything about this stuff.

[Bill Fitzmaurice]

[quote name='Protium' post='526297' date='Jun 27 2009, 04:39 PM']How do
If I want to wire up an 8ohm tweeter with an 8ohm woofer do I need a full crossover or can I get away with just using a high pass filter @ 4kHz on the tweeter?
Cheers[/quote]
You can get away with it, but you shouldn't. High frequency output from the woofer will have a different phase response than the tweeter, causing destructive interference, and the impedance of the cab above the HF corner frequency will be 4 ohms, not 8. Many cab manufacturers do use a high-pass only, not because it's the right way, but because it's the cheaper way.
BTW, if you're adding a tweeter it should cross no higher than 2kHz with 12s, 2.5 Khz with 10s. Manufacturers usually go much higher, it's true, but as for why they do, see above.

[fatgoogle]

Bill were should i cross if i want to add a tweeter to a 15" cab. I believe the speaker says it can go to 4khz.
Sorry for the hijack.

[Bill Fitzmaurice]

[quote name='fatgoogle' post='526610' date='Jun 28 2009, 06:52 AM']Bill were should i cross if i want to add a tweeter to a 15" cab. I believe the speaker says it can go to 4khz.
Sorry for the hijack.[/quote]
No higher than 1.5kHz. The axial response of the 15 may well go to 4kHz, though if it does go that high I'd be concerned about its low end, that's very much in the realm of a guitar driver. But irrespective of how high the axial response is any fifteen's response drops like a stone off-axis above 1.5kHz at best.

[Protium]

[quote name='Bill Fitzmaurice' post='526481' date='Jun 28 2009, 04:34 AM']You can get away with it, but you shouldn't. High frequency output from the woofer will have a different phase response than the tweeter, causing destructive interference, and the impedance of the cab above the HF corner frequency will be 4 ohms, not 8. Many cab manufacturers do use a high-pass only, not because it's the right way, but because it's the cheaper way.
BTW, if you're adding a tweeter it should cross no higher than 2kHz with 12s, 2.5 Khz with 10s. Manufacturers usually go much higher, it's true, but as for why they do, see above. [/quote]

Thanks

[stevie]

[quote name='Protium' post='526297' date='Jun 27 2009, 09:39 PM']How do If I want to wire up an 8ohm tweeter with an 8ohm woofer do I need a full crossover or can I get away with just using a high pass filter @ 4kHz on the tweeter?[/quote]
Unless you have measuring equipment, you don’t really have any option and it will be a bit hit and miss. Still, it can be done. What type of crossover were you thinking of using? Do you have specific drive units in mind? I’ll try to point you in the right direction if I can. Here's an example of somebody who's done it: [url="http://www.humblehomemadehifi.com/Bass-Rig.html"]http://www.humblehomemadehifi.com/Bass-Rig.html[/url].

[stevie]

[quote name='Bill Fitzmaurice' post='526719' date='Jun 28 2009, 02:15 PM']No higher than 1.5kHz. The axial response of the 15 may well go to 4kHz, though if it does go that high I'd be concerned about its low end, that's very much in the realm of a guitar driver. But irrespective of how high the axial response is any fifteen's response drops like a stone off-axis above 1.5kHz at best.[/quote]
If you try to cross a tweeter over at 1.5kHz you'll blow it up within a few minutes. Most of them are designed to be crossed over between 4 and 6 kHz. A very few will go down to 3 with a steep crossover, but 1.5k is the domain of the 1-inch compression driver - and high-end compression driver at that.
The crossover point for a tweeter is a function of its resonant frequency and the steepness of the crossover being used. Your Fane starts rolling off at 3KHz - so you should try for a crossover point of 4 or 5kHz, certainly no lower if you're just using a high pass.