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jessie.dazzle wrote:

The thraot size will be 7 inches.

Wow, THAT IS BOLD!!!! The 45Hz how from 7” throat – that is very-very cool and very positively-obnoxious.

jessie.dazzle wrote:

Yes I have thought about paying someone else to do the work, but that sort of skilled labor is super expensive around here.

Jessie, I just interested what money are we talking about? A few months back when in the GOTO thread:

http://www.goodsoundclub.com/LatestPosts.aspx?ThreadID=5901

Jeffrey Jackson suggested that to build the horn similar that he has built for the GOTO distributer he would charge around $15K. As I understand you are a software engineer, so with $100/per billable hour of your salary the $15K is just a little bit more than a month of work. Do you think it worth to consider? Also, you are in Europe and get paid in Euros and you can always found a builder  to who you will hay lea - in countries with their economic:  China, Russia, India, USA, Mozambique, Mexica, Taiwan etc…

jessie.dazzle wrote:

And... Yesterday I had a sort of "big day" with regard to defining the process. I'm still working it out, but it may not involve breathing chemicals, and could be quite simple.

Hm, will it include a wishing well; the seven lit cane and a necessity to sacrifice a chicken?  Well, perhaps I know little about the building technologies but within my clouded views the 7-throat to 45Hz will be pain no matter what you do…

jessie.dazzle wrote:

On another subject : I'm considering having all drivers remagnetized via a local guy who used to deal with Vitavox (and other) drivers.

Do not forget to make the measurements of the flux before and after. That would allow you in future to monitor your driver’s charge.

jessie.dazzle wrote:

The only difference I can see between the K15/40 and the AK151 lies in the resistance of the coil; the K15/40 being wound for 15 Ohms R, and the AK151 for 7 Ohms R. (In fact, the cone replacement kit one installed would allow him to change between the two drivers). According to the spec sheet, the K15/40 was intended to be used as a direct radiator. The AK151 was intended to be horn-loaded. Vitavox's resoning here must have bene that once loaded into a horn, the impedance in the case of the AK151 would come up. (Impedance at 400Hz for the K15/40 is 15 Ohms. Impedance at 400Hz for the AK151 is "determined by the charastics of the associated horn")

I never thought that impedance maters. I was thinking about impedance when I used off the shelf amps but when I went for my own amps and was able to moderate the plate load myself then I became much more flexible with impedance requirement. Anyhow, I did not play a lot with differences between the AK151 and K15/40. When I decided to stop with Vitavox bass drivers I confirmed foe myself that they were better then 515G and it was the further I ever went as I did not have a proper horn. However, in my mind I was thinking about 9-10” throat. You went for 7” – it is much nobler but it I still the 15” driver…  You will have too large front chamber. It will give you more gain but no one knows what else it does with sound. Generally for 7” hole I would like to see 10” driver… but I do not know any 10 incher of good sound. The LF section of Tannoy Red or Silver would do but they have 100dB less sensitivity then necessary…. I would look more or perhaps try to use the Vitavox 15” and to see what happen… Thankfully you will have so much aggravations with your horn that the driver size will be the least of them… :-)

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