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In the Forum: Horn-Loaded Speakers
In the Thread: This new midbass horn dilemma

Post Subject: A few things to consider.Posted by Romy the Cat on: 1/25/2014

noviygera wrote:
I got this new midbass horn to replace the Edgar 80Hz straight horn. It is made by Funktion-One and they claim it plays down to 90hz. I could not get it to play below 120Hz and I am trying to figure out why.

15" driver. The mouth is 39"x17". It is 34" deep from mouth to driver. Looking at the impedance sweep, there is a resonance at 80hz.
So the thing is that it sounds much better than the Edgar midbass but I cannot get it to play to 90Hz or even 100Hz, but I would like to. Because the sound is promising.
What is it that's preventing to play down to the claimed 90Hz? Too small back chamber? If that is the case I am willing to spend time and effort to enlarge the back chamber...

Gera, I do not know the horn and the driver they use. The miss presenting the measurements by companies is a common thing and it might be the case.

The horn is kind of strange for 90 Hz. With mouth 39"x17". You have 660 sq inch that is neat half of what you need to get a full 90Hz. I do not do exact circulation but my 36” spherical horn has 1017 sq inch and it rated for 115Hz. In addition my horn has much smaller mouth which accuses higher horn EQ. The Funktion horn has a bit driver, unnecessary phase plug… strange horn. From a different perspective they rate it i109dB sensitive, if it is true then it is very good but I do not think it is true. Even if they make 103dB driver (which would be VERY good) I doubt that this horn will yield 6dB gain. It might do it at 180Hz but not at 100Hz. So it was mis-advertising, very frequently happens BTW…

Anyhow, if you do like the sound of the horn then there are a few things you might try. First, the resonance at 80hz is obviously too low. You can try to raise it by changing the size of back chamber will work but it is re-building the horn and I do not know if you want to do it.

http://www.goodsoundclub.com/Forums/ShowPost.aspx?PageIndex=1&postID=6011#6011

If I were use I would target 110Hz of resonance and will see what happens.

Also, my 115Hz upperbass in my former listening room did 90Hz as it was installed in active spots:

http://www.goodsoundclub.com/Forums/ShowPost.aspx?PageIndex=1&postID=4421#4421

In my current listening room I have 130Hz and this is normal. Move your upperbass to the active location of your room and you might get much better response.

Many people feel that it is super important to get max LF response from the upperbass and I do not feel it is right direction. It is more important to make the upperbass do not strained. It is very hard explained over internet what does it mean. A few days ago I had a visitor who after a few hours of listening of my playback was asked what was the most characteristic behavior of my playback. He said that it the playback has a surprising enthusiasm to push sound out itself. He was very intelligent guy in my estimation and he did pick “it”. The reason I am saying it to illustrate that the enthusiasm of pushing sound out does not come from stressing of the channel but from making each channels to operate in the zone of own topological comfort. If you upperbass does not go too low in your room them do the best to the topology of the upperbass and then let the midbass channel to handle the rest. Horn people love to stretch the channels to the margins and it is not good in my view.

Rgs, Romy the Cat.

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