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Trachorn upgrade; initial results


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On 7/4/2005 12:40:15 PM jim-analog wrote:

Greetings,

I received the Fostex transformer attenuators via next day shippment. Installed them into the H/F line (EV-T350) and they work great. As far as I can tell, either by using the zero attenuation setting or bypass they don't seem to have any adverse effects. The finish work is very good, no clicks or noise when changing settings. It's very nice to have 1dB flexability for adjustments.

Al K., would these work either as replacement for the midrange auto-transformer in your original x-over networks or be better placed down line? I'd like to have the ease of setting change and 1dB increment for the midrange driver. I'm sure that most users would "set and forget" the midrange, but I've found that different source material can benefit from a balance change; sort of like adjusting the levels as a type of "equalization".

Anyway, even though the Fostex units were on the expensive side (about $170/ea), I do recommend them to anyone seeking the fine degree of control, neutral sonics and ease of adjustment they offer.

Regards, Jim

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I just picked up a Behringer DEQ2496 for $250 at Guitar Center. Seems like an easier way to go with a alot more flexibility. You can store 10 eq curves and it has a built in pink noise generator plus many more features. It also has a 31 band graphic eq and a 10 band parametric if you so choose. This tool will give much greter control if you can get over the fact that you are using an EQ.

Chris

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Jim,

I suspect that Fostex transformer would be fine for attenuating a squawker or a tweeter. I don't think I agree with Chris tough. An equalizer can't "shelf" a single driver up or down like an attenator connected to that specific driver can.

BTW: I just finalized the PC board for the transformer attenuator that I will be making available and I expect to order them tomorrow (July 5).

AL K.

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Mick,

The Altec 902 is a fine driver and will work fineon the Trachorn. It will even fit directly with no adaptors. I really don't like running 2-way though. I don't beleive any big horn designed for low frequency can work as well up high as a smaller horn (tweeter) can. I am using JBL 2426H drivers on my Trachorns but I am crossing over to Beyma CP25s to handle the highs. I think the Altec 902 is a better driver than the JBL. I don't think it will take as much power though.

AL K.

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On 7/4/2005 7:10:36 PM Al Klappenberger wrote:

Mick,

The Altec 902 is a fine driver and will work fineon the Trachorn. It will even fit directly with no adaptors. I really don't like running 2-way though. I don't beleive any big horn designed for low frequency can work as well up high as a smaller horn (tweeter) can. I am using JBL 2426H drivers on my Trachorns but I am crossing over to Beyma CP25s to handle the highs. I think the Altec 902 is a better driver than the JBL. I don't think it will take as much power though.

AL K.

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Al,

How low will the 902 go (is it fit for the K Horn or just the belle and lascala)? How does it compare to the K55?

Chris

PS: I was just throwing the eq idea out there. $340 to attenuate two tweeters sounds expensive.

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The Lansing Heritage site lists the Fr as 500 hz to 20,000hz, and power handling capability of 15 watts. The K-horn needs a midrange that can go down to 400 hz, you might try it and see. I doubt that you could get much power into it before the diapragm hits the phase plug, although it may be fine for low power useage.

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Guys,

Like Mike said, the 902 is only supposed to go down to 500 Hz. Most of these low frequency specs state a low limit based on how steep the crossover slope is. If you use my ES400 extreme-slope network you are killing everything below 400 very quickly. This will allow you to run the 902 more safely down to 400 Hz. It's the extreme lows that get through a gentle slope filter that rams the diaphragm into the phase plug.

Al K.

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Greetings,

Al and Chris, thanks for the suggestions. I have a very nice EQ in the system (Manley Labs Massive Passive, a very unique product:

http://www.manleylabs.com/containerpages/masspass99.html)

but feel that using EQ is "cheating" to some degree. I'd prefer to acheive balance with the crossover and attenuators if at all possible, using EQ only when absolutely required. Yes, it was quite a bit of $ for the attenuators and probably overkill for use with the tweeters. I may end up placing them in the mid range line when AL gets his units on the market. It will be less of an issue when I return the system to bi-amplification.

I spent most of Monday tweeking settings and though things are improving, I'm not yet close to my expectations.

Still seems to be a problem finding a midrange driver that will work with down to 400Hz without an extreme slope or power limitation.

Regards, Jim

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On 7/6/2005 7:38:16 PM D-MAN wrote:

I'm using the older-cheaper D-305 phenolic, 75 watts.

Works great, 2" throat. Used to crossover at 375Hz until I got the ES-600 network.

DM
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Dman,

Would there be an advantage to switching my K55's out with the Selenium D405's in my K Horns? (I realize that I will need new horns that fit the throat, I plan on changing my squakers). I like the change from the K77 tweeters to JBL Baby cheeck, buit if there is no effect, or a minimal gain, I will stick with the K55's.

Chris

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Is trying to adapt a 2" throat driver to a 1" horn(Trachorn)acceptable? Does'nt seem like it would be but thought I would ask. I know guys go from 1.4" and 1.5" drivers to 1" horns but 2" seems like a stretch.

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Hi Al,

I looked up this JBL driver and it specs minimum 500Hz w/ 800Hz/12dB/oct. Are you using this with the exteme slope x over? Would it work with your original x over? Thanks!

Regards, Jim

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On 7/4/2005 7:10:36 PM Al Klappenberger wrote:

I am using JBL 2426H drivers on my Trachorns but I am crossing over to Beyma CP25s to handle the highs. I think the Altec 902 is a better driver than the JBL. I don't think it will take as much power though.

AL K.

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Jim,

All of my networks use the 3619 transformer and swamping resistor. That allows them to run ANY driver. The only factor is how much power and how low in frequency. The extremem-slope filter allows any give driver to safely operate lower becasue the lows just below the crossover are attenuated much quicker to the 25 dB down level. It's the lows below the cutoff that kills drivers.

Al K.

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Hi AL,

Thanks for the response. I should have phrased my question differently though. I understand exatly what you're saying; what I'm trying to determine is if it is safe to operate the JBL driver at 400Hz/6dB oct. As it's a relatively high power handling driver, would say 25 watts (max) of input at the above stated xover/slope be workable? That's why I asked which xover you were using. Thanks!

Regards, Jim

On 7/8/2005 12:48:06 PM Al Klappenberger wrote:

All of my networks use the 3619 transformer and swamping resistor. That allows them to run ANY driver. The only factor is how much power and how low in frequency. The extremem-slope filter allows any give driver to safely operate lower becasue the lows just below the crossover are attenuated much quicker to the 25 dB down level. It's the lows below the cutoff that kills drivers.

Al K

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Jim, aren't you using the ALK? If so, you are 12db/octave for the squawker, not 6db/octave. If you use the JBL with the ALK, and use taps X and 4 -- I think you'll be fine along as you don't get carried away. Which of course means that option is out of the question for me.9.gif

Did you run those sweeps, and what did they reveal? What tap settings did find worked best with the Trachorn?

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