[navin]

I have exactly one audiophile friend in Mumbai (India). I know many but there is just one guy (he is about 20 years older than me) with whom I can have long discussions over the virtues of various amplifier topologies, loudspeaker designs and everything from LPs to computer audio.

I was showing him some pictures of the new Selah speakers I am working on - the Tempesta Extreme and  a sub-less RC4 (that looks like a Peridot). Both are ported (bass reflex).

What struck him was the lack of use of Passive Radiators. Ever since another loudspeaker designer showed us the benefits of using passive radiators  (mostly on the fly tuning) is his Faktor and Note loudspeakers I have always wondered why more designers do not use them.

The Note 7 if I remember right used a pair of rear firing 6 x 9 ( or was it 8 x 10) passive radiators mated to their dual 7" woofers. The Faktor 2 (like the Sonus Faber Concerto) used a rear firing 8" passive in conjunction with a 6" front woofer.

http://www.uberphon.co.uk/event3.htm

Rick, is there a reason you have not used Passive Radiators more regularly (I know about the Tres Supremo)?

[Rick Craig]

I have exactly one audiophile friend in Mumbai (India). I know many but there is just one guy (he is about 20 years older than me) with whom I can have long discussions over the virtues of various amplifier topologies, loudspeaker designs and everything from LPs to computer audio.

I was showing him some pictures of the new Selah speakers I am working on - the Tempesta Extreme and  a sub-less RC4 (that looks like a Peridot). Both are ported (bass reflex).

What struck him was the lack of use of Passive Radiators. Ever since another loudspeaker designer showed us the benefits of using passive radiators  (mostly on the fly tuning) is his Faktor and Note loudspeakers I have always wondered why more designers do not use them.

The Note 7 if I remember right used a pair of rear firing 6 x 9 ( or was it 8 x 10) passive radiators mated to their dual 7" woofers. The Faktor 2 (like the Sonus Faber Concerto) used a rear firing 8" passive in conjunction with a 6" front woofer.

http://www.uberphon.co.uk/event3.htm

Rick, is there a reason you have not used Passive Radiators more regularly (I know about the Tres Supremo)?

It really depends upon the application and cabinet layout. In some cases the PR's are excursion limited and / or are too small. In the case of the Tre Supremo the PR was designed for that specific woofer and also provided a tuning that was less practical with a port.

[navin]

It really depends upon the application and cabinet layout. In some cases the PR's are excursion limited and / or are too small. In the case of the Tre Supremo the PR was designed for that specific woofer and also provided a tuning that was less practical with a port.

In practice do PRs give an impulse response that is comparable to a bass reflex box? The PRs I have heard don't seem too shabby with impulse response.

[Rick Craig]

In practice do PRs give an impulse response that is comparable to a bass reflex box? The PRs I have heard don't seem too shabby with impulse response.

I've never really looked into that. I know some feel there's an issue between the various box loadings but I've never felt it to be audible.