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View Full Version : anyone convert their A7 VOT over to a three way,,??



Derry
04-28-2010, 07:28 PM
I'm in process of reworking my A7 cabinet and while I have everything apart was thinking about changing it over to a three way and adding a good ribbon or cone tweeter to handle those highs in the 10K and above range,, I have never found the horn to be as clear or precise as a good tweeter,,

my A7s have the N-800E cross over with the 806A driver and 811b horn,, the woofer is the 416A and both speakers are in excellent condition,, I am the original owner,,

thanks

Derry

eso
04-28-2010, 08:04 PM
I own a very old pair of A5s (828 cab/515B driver, 1005A horn/288b driver, N-500-C crossovers) and I did run them with a tweeter at one point.

A cone or ribbon would not be a good choice in my opinion because you'd have to pad the whole system down considerably to integrate a tweeter that probably has a sensitivity well under 100db.

I used Fostex T-925A alnico horn tweeters and only added a 1f cap from the high output of the crossover. They worked well and really added some sparkle that is lacking in most stock VOTT systems. Since that I purchased those Fostex cam out with the T-500mkII that is a much better unit but much more expensive.

There are some other options including JBL 2404-5 (?) and similar JBL tweeters that are clean and have an output that will match the existing system output. To use a tweeter that is lower efficiency is to undermine one of the greatest strengths of the system you've got: Totally counter-productive.

eso

Derry
04-29-2010, 06:16 AM
thanks ESO, been reading a lot more and I do agree on another horn type for the tweeter,, I had been looking at the T90A (tad lower in price) as my main candidate,, my A7 has the horns mounted inside so the addition on the top side would be easy ,,

I was planning on the Altec horn doing the work from 800 to 8K and the Fostex from there on up,,

what levels did you find best for crossovers with the Fostex,,

thanks

Derry

Cosmo
04-29-2010, 08:41 AM
You may want to try a Electro-Voice EV-T350 they come up on eBay all the time but are quite expensive $ 5-700 a pair but sound quite nice

scott fitlin
04-29-2010, 08:51 AM
I use Altec 815,s and 817A,s and 816,s. Originally we had Altec 311-90 and 811 horns, and later switched to the JBL 2395 lens.

In the original 2 way configuration, the HF was just not extended enough, and we added JBL 2402,s and later also 2404 bi-radial tweeters. We also added subs, and what I do, is let let the 15,s run all the way down, and roll off naturally, BUT I cross the horns over where the tweeters come in at 7k. Rolling the horns off at 7k where the tweeters come in alleviates the comp driver and horn from becoming harsh sounding, as well as the lens doesn't really do very well above 10k anyway.

It becomes a matter of taste as to which tweeter one likes, and the tweeter does the VHF well, and the horns do what they do well, and this works great.

herki the cat
04-29-2010, 10:55 AM
I have never found th...(811-b ??)... horn to be as clear or precise as a good tweeter, my A7s have the N-800E cross over with the 806A driver and 811b horn,, the woofer is the 416A and both speakers are in excellent condition,, I am the original owner,
Derry

herki
Well, 811-b horn cuts off too early for 800 Hz cross over. You need one or two octaves horn loading bellow 800 Hz cross over to get rid of the 811-b horn honk. A 511( ) horn or JBL Radial horn equivalent of 511( ) horn will work very well at 800 Hz crossed over with simple 1st order, 6 db / octave roll offs with HF extention well up to 12 kHz or so.

Temporarily for tweeters, until you can fnd JBL Radial HF 800 Hz horns, You can use the 811-b horns above 7 or 8 kHz crossed over also 1st order with nice JBL LE175, or LE-85,or 2410 or 2420 drivers for tweeters and essentially keep all three voice coils in the same plane for coherent blending of the three horn wave fronts.

Note there is something magic about the JBL LE-175, LE-85, 2410, & 2420 drivers in the extreme high frequencies with JBL's extremely high flux density & original aluminum diaphragms ---in my book---really world class.

Derry
04-29-2010, 12:23 PM
thanks for the continued support,,

was planning on removing the 800E network and crossing the 416A woofer over at 1K and then using the 811B horn from 1K to 6K and a good tweeter for the 6K on up,,

Derry

rudy sesztak
04-29-2010, 02:01 PM
Try to get a pair of used JBL 077 tweeters. Use them from 7k up. Ther great tweeters.It will make the high end response COME ALIVE!- RUDY SESZTAK.

4343
04-29-2010, 02:50 PM
Try to get a pair of used JBL 077 tweeters. Use them from 7k up. Ther great tweeters.It will make the high end response COME ALIVE!- RUDY SESZTAK.

077=2405

I use those with my big lenses, and with phenolic (1") diaphragms to fill in the top octave, 10K up. Alive it is...

robertbartsch
05-03-2010, 03:40 AM
the 2405/077 JBL tweeters are a good match to extend VOTT which I have used for 30 years with good results.

i would cross these at 10k or so.