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unicon wrote:

what you did in your horn :  you coupled your horn and you added mass on cone. then imagine when the cone tried to make an impulse it moves forward and then in back chamber something stops it from moving(air pressure+-) your driver had been stopped from moving from back and horn chamber.

Yes, I did, it is a normal practice in my view how to tune back chamber. I did nothing more then follows my own guidance how it need to be done:

http://www.goodsoundclub.com/Forums/ShowPost.aspx?postID=2991

unicon wrote:

I suggest make you back chamber as large as you can or just make it infinite chamber like or isolate the back roof side areas.

Come on unicon, get some practical perspective on the subject. The measurement of the horns in semi-assembled state in the basemen was an attempt to get an APPROXIMATE back chamber size, in order to guess what to build. Of cause it would be great to make the back chamber “a large as you can or just make it infinite chamber” but when you have a carpenter who ask you what the demotion of the specific surface shall be then we need to stop operate by imaginary concepts and be very practical. The whole idea to make a test chamber that I have built and to find it’s size when the resonance frequency would be too high and too low. It is what I did and from that I intimated the back chamber size. Who knew that the reflections in the basement were so effective? I would refer you to my old post I made 3 days before we started the project:

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=13990   

I very much questioned how the resonance frequency will change at floor level where I could make experiments to the cathedral ceiling level. I thought it would be 5Hz difference, but it turned out to be 22Hz difference. Well, now I know, now even you know….

unicon wrote:

in my idea in infinite chamber you can avoid some unwanted resonances like that  125 315 hz( if its not due to your horn mouthing sizes )

Hmmmm, I do not think so. With open back I do have infinite chamber, you can’t make bigger chamber then open air. I do not think that there are any correlations between the unwanted peaks you see on horn response and anything in back chamber. The peaks are most likely are room related and has nothing to do with horns and impedance on those frequencies is dead stable (I tested it). Sure I would need to find a way to deal with the peaks and most certainly with the 100Hz suck out but it will be a very different subject and it will hardly had anything with the back chamber. BTW, my carpenter did propose me last night to add a few feet of the back chamber; the way how the back chamber was designed we did have a provision to let it to grow. I declined the offer foe now. Let see how it goes…

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