GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Horn-Loaded Speakers
In the Thread: Macondo’s Midbass Project – the grown up time.

Post Subject: Some data, impressions and me.Posted by Romy the Cat on: 8/27/2010

A friend stopped by tonight when I was test-listening my midbass horn. He got freaked out from the size of the thing. I played for him some Gerhard Oppelt’s organ recordings. He told me that I am crazy, like I do not know it myself. Anyhow, he made a picture of me and the horn and ran away. Here me and my new baby.

I did measure the loaded Vitavox 14/40 - it has two resonance 24.5Hz and 68.7Hz, it is a good drop from 50hz in open air. The 24.5Hz was semi-expected but the 68.7Hz made me to puzzle. I all to Bruce Edgar and he explained to me that it is normal for long hyperbolics and I shall wary only about the lower one. I did not have the double resonance with shorter fast opening horns. Anyhow, now the key is to find the right size of the back chamber to drive the resonance to my reference 42Hz. I have made a test sarcophagus and tomorrow will try it out. I think it will be a very small box, right behind the end of the driver, even perhaps smaller. I will make the picture tomorrow and publish the data with the final found volume/dimension.

The right question would be how does it sound? I would say good and bad. Sonically it is not the sound that I like it it has no right pitch definition; it has lot of LF noise and a lot of other things that I would like to have. It however sits in basement room pointed to a wall, has no filter, no back chamber, no glued horns, driven from a table radio. I am sure it will be a lot of better. In a good side it was stunning density of sound and it has gain and john EQ MUCH more than I expected. This thin has HUGE gain I mean stupendous gain. I think that it in vicinity of 12dB -14dB, sure the room added some but it is very certain that we are not in the 6bB of my typical fast opining upper frequency horns.

I was trying to extrapolate how the horn will behave upstairs. The gain of the thing truly astonished me. Even with Fs of 20Hz lower what it has to be it filed my 1750 sq feet basement with huge bass and what it important that the driver practically not moving. With back chamber it bell be even less and this is super important. I played music as lowed and I was able to handle and the driver was moving out no more than 1mm-2mm – stunning! So, the gain and EQ is totally out there. There is one thing that I hope will work upstate to me benefit. The 43Hz has wavelength 27 feet. This is approximately the distance of the midbass horn mouth to the opposite wall. So it I will be lucky then I will dive in-phase return from opposite wall that might give me an extra boost in… 42Hz. It is hard to predict will see…

The Cat

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