A7 Assembly

[Lunes]

Hello everybody,
I've just finished my new selfmade 828 cabinet construction and my next task on the way to finish the whole assembly would be the crossover.After going a little deeper into it as a bloddy beginner I had to realize that my 416 LF Woofer are 16 Ohmer and my 288 HF Driver are 8 Ohmer.
Now my question is if you see any chance that this will become a really good sounding
home hifi application.
Any help would be appreciatet.
Thanks in advance.

[thevott]

Personally I would not hesitate to bi-amplify the system. That is, utilizing an active crossover network and use separate power amplifiers for the low and high frequencies. Such a configuration does not require your drivers to match as with passive networks.


MP

[Fitts]

I agree with TheVOTT, bi-amping is the best way to go. I have done that to my A7 cabinets which have 8 ohm woofers and 16 ohm horns. I don't plan to ever go back to passive crossovers.

If you already have an 8 ohm crossover, you can turn the 16 ohm woofer into an 8 ohm one by putting a 16 ohm resistor across the terminals, a 16 ohm resistor in parallel with a 16 ohm woofer is 8 ohms of electrical resistance to the crossover.

Last, when building your own crossover, there is no requirement that a woofer has to have the same resistance as the tweeter or horn. It is possible to build a crossover that would work using your 416 and 288 drivers.

Regards,

[dennis gilliam]

I'd just go ahead and run your CO as planned. Typically, the overall impedance of the woofer varies widely and really goes up as efficiency vs. frequency goes down. Linearity may suffer slightly in reproduction, but in the home environment where you will seldom be putting more than 20 Watts into the 416, won't bother it in the least. If you feel the bottom end is a little off, you have those wondrful treble and bass controls...

DG

[joejoe723]

I wondered that the 416 can be used with with 288???
The 288 sensitivity is more higher than 416.

[Fitts]

Hi Larry Larry,

Even though the 288 is more sensitive than the 416 per watt of power, a resistor attenuator can be added to the 288 crossover to balance the output of it with the 416.

In my case I have a bi-amped system and have to lower the volume to the HF drivers quite a bit to get them balanced.

Regards,

[Gerald DiMauro]

Hi thevott,
I have a question. I've been playing with three different active cross overs on my 19's. I am bi-amping them and trying a Rane AC22, a Furman X-324
and a Behringer CX-2300. I like to have the capability of playing with the sound but I feel that using an active crossover adds noise/hum. I know you're probably thinking that I have a ground problem, cable problem or other electrical interface problem but I don't. It's just the actual crossover device that adds a slight bit of noise/hum. Do you experience the same thing and if so what are your thoughts on this? Thanks in advance for your reply.
Sincerely,
Gerald

[Fitts]

Hi JDM,

I have a suggestion that may be way off base but I will offer it for your consideration.

I had a McIntosh integrated preamp/amp, a Crown preamp and a Crown amp. The Crown preamp feeding the Crown amp made for a very quiet and noise free system. The McIntosh preamp feeding the McIntosh amp was also a great system, absolutely quiet and noise free.

If, however, I plugged the Crown preamp into the McIntosh amp or took the output of the McIntosh preamp and fed it into the Crown amp, the noise and hum were noticable in both cases.

This made no sense to me until I began to look at some of the specs. As I understand it, the McIntosh preamp/amp I had was high impedance and Crown equipment is all low impedance. I also noted that the Crown amp had no input capacitors like the McIntosh amp appeared to have. All of this seems to have had an effect on hum and noise and seems to be the reason I could not get these two great systems to work together.

I could be all wrong here but I think the active crossovers you have been trying are all low impedance. It might be that your pre amp and amp are high impedance devices that do not work well with the low impedance crossovers you have been trying.

Just a thought,

[Jim Easley]

Gerald,
Dave has a good point. The active crossovers you mentioned all have balanced inputs as well as outputs. If you are using unbalanced equipment with these components, the wiring and setup can be tricky. Most professional balanced equipment works best in the 0 to +4dBu range. It is not unusual to find balanced equipment that can output up to +28 dBu. You should try using different gain settings to optimize the noise levels to minimum. It takes time, but the end result is well worth the effort.
Jim

[Gerald DiMauro]

Dear Dave and Jim,
Thank you both for the input. I guess I need to pay closer attention to this. I will get help from my friend who is letting me use his equipment and show him your posts. I'll get back to you guys with results. Thanks again.
Gerald