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In the Forum: Audio Discussions
In the Thread: NOhorn channel for “the melody range”.
Post Subject: A port with a 'human face'.Posted by Romy the Cat on: 6/26/2008
 haralanov wrote:
I’m still in the world of direct radiators and I’m looking for the ultimate midbass channel solution. At this time it’s still impossible to build a horn of this size so my purpose is to find the next most good sounding solution. Some time ago I found very appropriate driver for upperbass reproduction – ScanSpeak 18W/8535. It has smaller magnet system (and little lower efficiency) compared to 8545. The cone material is the same as the famous 25W/8565-00 bass drivers and it has very good tone up to 600-650Hz.
Yes, I do know the ScanSpeak 18W/8535 driver, it is a good driver. If use it then I would have a concert about is about its suspension. For lower frequencies driver the ScanSpeak own low-resonance rubber surround (that feel more like foam) is OK but if you wish to starch it to 650Hz then it need to be re-evaluated. It might be OK, I just do not know, those I personally my prefer papers, cloth of lather suspension. The driver that will be 6dB closed at 650Hz will have a lot of put at 1000 and 2000Hz, so you need the “ringy” tail capable of transients. Most of the rubber-suspended driver has horrible transients at HF and rubber sucks HF like a vacuum cleaner. So it is all how the mass/material/structure of the cone “talk” with It’s suspension. Here are no measurements or any other abstractions would show nothing – you need to listen the thing to decide for yourself. It is very possible that ScanSpeak did a fine job with it. I think this driver is used in by Wilson extensively and the Wilson’s upperbass is extremely good (down to the point where the port ‘noise kick in and screw everything up)
 haralanov wrote:
Romy, is there something you have found about ported enclosures and rejected the idea above?
Well, I think that if to use port but do not USE the port’s output for sound shaping then it might be useful. I know it sound as a contradiction but it is not. I feel that the definition of port success would be in VERY judgmental point where the output from the post shell be stopped. If port gives for instance + 8dB at 40Hz then it is possible that at +3dB it still would be OK sonically where port would not sound like port. How to make those decisions during a design stage I have no idea as there are many other variables involved into the decisions process.

The caT

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