Passive or active?
April 7, 2004
Would you recommend using a passive crossover with a
non-powered subwoofer, or should I just use an active subwoofer crossover? This is for a
DIY sub I'm designing.
Ronald Montgomery
I'd suggest you use an active subwoofer crossover.
You'll gain valuable flexibility over the high- and low-pass crossover frequencies, and
depending on the model crossover, you'll also have adjustable phase. These controls will
be invaluable when trying to integrate the subwoofer into your room. If you don't have an
amplifier yet, I'd look into a "plate" amp, which is a power-amplifier module
designed with an active crossover built in. These are made at numerous price points and at
various power-output levels especially for applications like yours. They're even made to
mount flush in an MDF cabinet. Several models are available at www.adireaudio.com, to give you a
start.
Next equipment reviews
April 5, 2004
Can you tell me what reviews you'll be posting next? I'm
really enjoying your website and am getting ready to buy a new system, so I don't want to
miss anything I should be looking into.
Franco
We've got some excellent products upcoming for you
to read about. On the speaker front you'll learn about the Quad 21L, a small British
floorstander. After that comes the TLP 1 preamp-tuner and PVA 2 power amplifier
from the Canadian brand Anthem. Great stuff on the horizon!
Subwoofer crossover frequency
April 3, 2004
Do you think crossing over a subwoofer at 250Hz is too
high? I have a small set of bookshelf speakers and was thinking I needed to get a
subwoofer that crossed over pretty high to have good midbass and a full sound. Thank you
for your help on this.
Ricky Puente
I'd say 250Hz is likely too high. Subwoofers are
designed to reproduce very low frequncies: generally speaking that means below 150Hz. Most
subwoofers that I've come in contact with have an upper-frequency limit below 200Hz. As a
general rule, a low-pass crossover frequency of 80Hz is a good place to start
experimenting ("low pass" means frequencies below the stated figure will
"pass" to the subwoofer). If your speakers are really small and bass-challenged,
you may bump that figure up to the 100Hz mark, but the sound will likely start getting
muddy much beyond that. Experimentation is the key, though, and proper placement of the
subwoofer is just as important as crossover range when it comes to attaining good sound.
Replacing drivers in his
Cerwin Vegas
April 1, 2004
I have a pair of Cerwin Vega D-12s that are about 12 years
old. I was thinking of replacing the drivers with some that I've found on the Internet. I
have some woodworking skills, so I figure if the cabinets need to be modified some I can
do it. What's your thoughts on this? Will I improve the sound if the drivers are better
than the stock ones?
Reginald
Replacing the drivers in an older set of speakers can be
a tricky proposition. When a speaker is designed it is conceived as a system -- a system
that incorporates not only the drivers and their characteristics, but the crossover slopes
and frequencies, cabinet volume, materials used, etc. Without knowing all of the specific
design elements that Cerwin Vega used in your speakers, it's unlikely that you'll be able
to simply drop in new drivers and have them sound good. With your woodworking skill a
better alternative may be to simply build a new set of speakers from one of the many
loudspeaker kits available on the market today. These kits are designed to work correctly
from the start -- all of the design characteristics I mentioned above are calculated in
advance. You can buy a kit with all of the necessary parts included (including the
cabinets) and assemble them yourself, or you can buy plans and the do the actual cabinet
construction from the ground up. This can be a satisfying way to obtain a new set of
speakers. Have a look at www.madisound.com
to start, but check around. There are tons of options out there.
|
