Help me find a woofer that has a natural roll-off and may not need a x-over...

[navin]

i am familar with Thorsten. he helped me a lot when i was making my speaker (SS 8546-9900) in '94. In fact I did NOT take some of his advise and now wish i had so i have a lot of respect for him.

if only the manger was more affordable this journey of mine would have been a lot shorter!

 

[hunter audio]

Not a lot of difference in my book between a high

hi streten

i hate designing hi - inductance drivers , speacially to keep out mids and hi-s , its far too easy that way

my drivers use short coils of - copper / 4 layer in large gap geometry ,

yet copper is heavy - (4 layer = high inductance )

i have a preference for alumunim short coils in a reverse xbl 2 motor structure

i generally do not want to get into arguments here not my nature or the type as i have had a bad experience in diy

though if you are open for an indepth discussion on :-

- loudspeaker driver technology
- raw material devolopment
- machine devolopment to form cones , spiders , surrounds and the tools
- loudspeaker assembly line trouble shooting

i am open for it

suranjan

transducer design engineer

 

[kelticwizard]

Have you considered a 4th order bandpass design for the woofer? This encloses the driver entirely and only exposes a port. The curves I get when I use WINISD to model common 8" woofers in this alignment roll off at about exactly where I think you want to be.
(P.S - I'm a rookie at this speaker design thingie, so if this is a retarded idea - _someone_ should speak up!

Salex:

The idea is not retarded, in fact it would seem to be a natural.

It seems that commercially available bandpass designs give the perception of one-note bass. They are generally relegated to car systems, computer systems, and home theater systems for that reason.

Laurie Fincham of KEF was instrumental in introducing this configuration back in the eighties, and indeed KEF has introduced several highly rated systems that use this configuration. So it must have some sort of merit, if done right.

However, outside of KEF, nobody in the hifi world has shown much interest in doing it right, and the idea languishes.

People who buy or build full range systems like Greggo do so because they are after a completely integrated sound, with subleties that they feel a crossover destroys, no matter how well designed it is. The idea of matching such a system with a bass configuration with a reputation for power over accuracy would not seem to make sense.

I do believe that a 4th order bandpass system could be made that would fit in with this and sound good, but the division seems to be made. Outside of KEF, bandpass systems are just not usually considered when putting together a system designed to bring out subtleties.

 

[sreten]

Hi KC,

the "problem" with bandpass designs are as follows :

Allthough giving a large increase in power handling around the
crossover point this point has to be arranged to be where its
needed, somewhere in the 100hz to 150Hz area.

The port has to be very finely tuned for correct response,
far more critically than low bass port tuning.

The electrical load of the bandpass driver is useless above the
bandpass cut off point, so electrical filtering is still required.

The basic premise of KEFs design philosophy, that maximum
excursion is required in the 100Hz to 200Hz region is now
fundamentally flawed with the prevalence of low bass on
many CD's, biased towards exploiting DVD bass effects.

sreten.