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In the Forum: Audio Discussions
In the Thread: My feelings about new exciting audio products
Post Subject: A “lowest octave horn” is an oxymoron.Posted by Romy the Cat on: 6/27/2007

 coops wrote:
'Closed bottom'?

Look for the James’ thread about “Barn Conversion” :

we were taking there about the “opened bottom”  and “closed bottom” solutions. The Cessaro’s LF is horn loaded. Do not forget the horns do not “load” frequencies that are lower then the size of the mouth allow them. it is possible to get out of bass horn frequently lover then the horn rate. Altec did it with 515B driver and back-chamber with port but it is VERY different sound.

So, the Cessaro’s LF horns looks like have no more mouth opening that might support anything lower let say, then 60-70Hz. What happened next? Next we have an excessive polluting exertion of driver and a huge compressed boom coming from the horn mouth. You see, a properly operating and sounding bass horn should be high-passed and half octave (deepens of the slope) below the mouth’s rate. It will be high-passed by the horn mouth anyhow, but it is nice (for sound) to unload bass before the mouth’s high-passed kick in.
So, what we have in care of the Cessaro’s LF? We try to make bass section but we in the environment when bass should be …. high-passed. Very nice, thank you! It is what I call “closed bottom” bass salutation as bass by the nature of the topology does not allow itself to be developed free to it’s natural bottom. When you put a bass horns in “active zone” of you room:

then the room might still suck in another octave or two but the bass bins are high-pass itself out… not good at all… If I use something like Cessaro Gamma then would put a low-passed resonator at the bottom that would kick in at 30-40Hz….

The Cat

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