Wide Bandwidth System

Posted by: DAVOhorn on 15 February 2003

dear All,

My system is able to currently realise 35hz-100khz. Not bad but a bit lacking in the bass.

A friend and i have been playing with our own designs of Sub woofers.

So today i added a sub to my system and can now cover from 10hz upwards.

The sub uses a 21" bass unit and a 500w power amp module and crossover.

I really did not expect such a transformation to the system. I will probably have to rebuild the house within 6 months. But interestingly at normal listening levels if you listen to the sub only the output is not overpowering .The x over frquency is 60 hz so at the 35 hz roll off of the horns the sub is coming into its own and therefor does not adversely affect the sound from the horns.

A satisfactory days work.

regards David

Posted on: 15 February 2003 by hi fi fo fum

so how much more bass can you hear ? how big is your room ? why only 500 watts? one sub or two ? A company named "Hartly" made a sub woofer driver that was 24" dia. you should of used a couple of them.

Posted on: 15 February 2003 by Manu

Take care, i've mesure many rooms having a big resonance around 54KHz. Your system can trigger it, it is dangerous for your brain. Fortunately, it won't reproduce the second harmonic, this one is lethal at high volume.

Sorry, David, are you really serious.

Emmanuel

All opinions are my own, and reflect those of the organisation i work for, even if not stipulated.

Posted on: 16 February 2003 by DAVOhorn

Dear Guys,

Thanks for your concern.

I dont play loud never louder than 90 db.

Using test discs you are able using a sound pressure meter to measure what the speaker is doing in the room.

Bottom string on a bass guitar is about 40 hz.

Bottom note on a ground piano is approx 27 hz.

Bottom note on a large church organ is about 16 hz.

So as you can see having a speaker that can reproduce the full range of frequencies of common musical instruments is necesary .

So using a sub which is able to reproduce a pure 10hz tone is a reflection of its potential.
It does not mean that i am playing 10hz test tones at high levels.

Frequencies around the 6 hz and below can cause nausea and damage at high sound levels eg thunder storms etc.

But playing music eg church organ in your home at moderate listening levels eg 90db is not a health hazard.

regards david

Posted on: 16 February 2003 by Martin Payne

quote:
Originally posted by hi fi fo fum:
so how much more bass can you hear ? how big is your room ? why only 500 watts? one sub or two ? A company named "Hartly" made a sub woofer driver that was 24" dia. you should of used a couple of them.

Mr Fum,

I suspect this was a Precision Devices driver (David?) In the pic below, there is a 21" PD driver in the half-seen sub at far left with a cloth grill on.

The exposed driver is a 24 inch PD unit. IIRC, David was sitting just off to my left when this was taken. Disney use these drivers in their theme parks to simulate explosions and earthquakes at realistic volumes.

This sub is one of a pair and, I think, goes down to about 4Hz? (David?)

cheers, Martin

Posted on: 16 February 2003 by DAVOhorn

Dear Martin ,

you got it in one.

I bought simons 21" PD sub.

He is using two off cabs each with 24" pd . They go down to 4hz . the 21" does an easy 8hz.

Adam,

you are correct simon is the guy who ad a 5 page spread in April 2002 HiFi News.

Steve Harris was completely blown away by Simons system. I was there for approx 2 of the 7 hours that Steve Harris was there for.

regards David