3 or 4-way active High End speaker ???

[Jan Dupont]

Hello all,
I'm normally to find in the Solid State forum, however now I'm need some serious advise for my new active speaker systems.

At the moment, I have a pair of home made speakers with following drivers and passive filter:
Top: one 1" VIFA D26TG-05 and one Audax TW025a10
Mid: one 6.5" VIFA PL18WO09
Bas: one 15" No name crap bass

I've just got my hands on some high quality 15" bass drivers (99% equal to the bass drivers used in the new B&O BeoLab 5 1000W active speaker), and will use the oppertunity to make my self some state of the art active speakers.

As I see it now, for a 3-way system, the active crossover will be set to 200 Hz and 2 kHz. The amplifiers will be suitable 200-800 Watts each

However I have a few concerns regarding the 200 Hz crossover frq between the bass and the mid.

1. I'm afraid that the PL18 mid will sound pressed and distorted when handling high power down to 200 Hz

2. I'm not sure that I will get the right punch in the lower mid/upper bass

3. Could one or two extra 6.5" or 8" lower mid/upper bass from 150 to 500 Hz be a solution, without causing to many sound problems around the crossover frq's ???

What are your experiences????

[markp]

The Vifa is a very good driver with a lot of output capability in the midbass region, I dont think you will have a problem at all. If you are really worried, try a Scanspeak driver for truely great midbass and a huge x-max of +-6mm linear and 11mm max!

[Jan Dupont]

Thanks,
Do you have a special Scanspeak driver in mind ??

[Jan Dupont]

Maybe I forgot to tell, that total system power will be app. 1200 Watts pr. channel (just to have reserve for dynamic peaks)

[LineSource]

The datasheet for the VIFA PL18WO09 shows Sd=132cm^2 and Xmax=4mm and Pmax=100 watts. If you put it in a sealed box, as is often done to simplify the crossover and achieve the best transient response, the 4mm Xmax will allow SPL=109db/1m at 200Hz with about 20 watts of power.

[Jan Dupont]

LineSource
Thanks for your help.

I understand your calc as an upper bas would be needed to ensure high output handling capacity.....

[sreten]

Well JMO but you seem to have no idea of actual power amplifier
output requirements for active speakers to cover each frequency
range and 200/800 watts per amplifier is so way off its not funny.

I don't see anything that would qualify the speaker as "high end".

If your into designing amplifiers, fine, stick to what you know.

sreten.

[sreten]

But as an example 4 800w amplifiers used in an active 4 way
theorectically can produce peaks equivalent to the same 4
way with a passive crossover driven by a 12.8kW amplifier.

Active speakers are superb at handling wideband transient peaks.

(work out voltage swing per driver, and assume the "peak"
causes full voltage swing across each driver, not very real )

sreten.

[454Casull]

Originally posted by sreten
Well JMO but you seem to have no idea of actual power amplifier
output requirements for active speakers to cover each frequency
range and 200/800 watts per amplifier is so way off its not funny.

I don't see anything that would qualify the speaker as "high end".

If your into designing amplifiers, fine, stick to what you know.

sreten.

What a welcome to the Loudspeaker forum.

[sreten]

Originally posted by 454Casull

What a welcome to the Loudspeaker forum.

You're right, I should have been more polite, it reads worse
than what I was thinking, just trying to get someone to stop
and think, but as he's a veteran of the solid state forum I
wasn't thinking "kid gloves" are required.

srteten.