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Altec 902-8B Diaphragm Check and Muddy Blues (PIX included!)...


chops

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Both of you, go to the wood shed !!!!!!

Hey, I was just on here trying to get some answers. It's not my fault there's people on here who like to be wise-@$$es and start trouble all the time.

If you look back through the thread, you'll see everything was going on fine right up until "you know who" had to start shooting off his big mouth and calling me names as usual, ruining every single thread I start. You can tell what kind of person he is just by looking at his avatar.

I guess it's to be expected on this forum these days. And I'm the one who usually gets shot down simply because I stand my ground. Go figure... blah, blah, blah, etc, etc, etc...

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"Kryzzy Masterminds" bifurcation can lead to one of three outcomes (1)a complete

solution. That's fine (2) A contradiction. That too is fine: one goes

back to th epoint of bifurcation with the KNOWLEGE that the other

alternative MUST BE CORRECT (3) Another "dead end" This is the

difficult situation.

There are two possibilities - (a) select another square from which to

make a further bifurcation (an Ariadne's sub-thread, as it were) or (B)

forget the original bifurcation; go back to the grid as it then

appeared and select a totally different square from which to start a

completely fresh bifurcation.

The disadvantage of (a) is that a Ariadne's sub-thread has only a 25%

chance of being correct, so time spent pursuing it could be time

wasted. On the other hand if one is within sight of the end when

outcome (3) is reached, it seems a pity not to go on!

And that indeed is the key. If your second dead end is only a few steps

away from the original point of bifurcation, abandon that bifurcation

and select another bifurcation point - choice (B) in fact. But if you

end up more than half way towards the end of the puzzle then press on,

ie choice (a).

Remember though, Ariadne's subthreads are that more difficult to keep

track of. So the choice between (a) and (B) will in many cases be a

matter of individual preference and judgment. Bifurcation is not logic. Isn't it Trial and error?

If you must "Test" the validity of a choice, then you are in a trial, not a logical selection.

In programming, we understood that you can solve a problem one of three ways, (1) logic, (2) table lookup, (3) formula.

Trial and error is "brute Force", the least elegant approach to any problem.

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"There are a bunch of others out there that own these 902s and claim that they have plenty of high freq energy, even too much sometimes."

I am not one of them. Even with new diaphragms.

"This is why people add tweeters to Altec and TAD that measure flat to 20Khz already".

IB one of those guys.

tc

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IB one of those guys.

tc

IB one of those guys...too

Charles. I know you have put a lot of time in your project over the last several months. I've been following along pretty well.

Putting aside the high extension for a minute, are you finding the active crossover route to be of your likeing?

Are you against 3-way? Now my ears are very sensitive to high frequencies but the two way thing was a bit hard to come by for me. I must admit that I will give this another run in the future. I've just got other things on my plate that I want to try.

You are good at doing stuff on your own. Why not just build a high quality passive crossover going three way. I have been very pleased. I haven't compared it to active though...so I'm not saying it's better. My 902...511 combo is paired with JBL 2404. Sounds very good to me.

jc

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IB one of those guys.

tc

IB one of those guys...too

Charles. I know you have put a lot of time in your project over the last several months. I've been following along pretty well.

Putting aside the high extension for a minute, are you finding the active crossover route to be of your likeing?

Are you against 3-way? Now my ears are very sensitive to high frequencies but the two way thing was a bit hard to come by for me. I must admit that I will give this another run in the future. I've just got other things on my plate that I want to try.

You are good at doing stuff on your own. Why not just build a high quality passive crossover going three way. I have been very pleased. I haven't compared it to active though...so I'm not saying it's better. My 902...511 combo is paired with JBL 2404. Sounds very good to me.

jc

Hi jc,

Yeah, I really like the active route very much. Contrary to what some say about the "wonderful sound of op-amps", this Rane crossover doesn't add anything to the sound at all. It's dead silent all the way and is crystal clean, likewise with the Rane Ballance Buddy and Crown D-75A amp. There is only the very slightest hint of hiss coming from the horns, and even then you have to have your face right in the horn to be able to barely hear it.

I love the fact that I can tweak the output of both drivers independently of eachother along with the delay on the woofer. The delay alone was a vast improvement in overall sound, once dialed in.

As for if I'm against 3-ways, I don't exactly hate them, but there are greater gains to be had with a well setup 2-way. I think 2-ways are much cleaner and natural sounding. I've always preferred 2-way speakers anyway.

And as far as the top end is concerned, that has all be taken care of as well with a Behringer DEQ1024. Again, this unit is also dead quiet and doesn't add to the sound either, except for where I've adjusted the EQ of course.

As you can tell from the pic below, I am only using the EQ for the top end. Tomorrow I'll pull out the mic and fire up TrueRTA to see where this EQ gets me. I haven't done any measurements since I got all of these extra goodies, so it will be interesting to see what effect the new active crossover has made to the overall system response as well.

IMG_0936.jpg

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If you're willing to put an EQ in your system, then perhaps you should

consider a constant directivity horn with the typical CD EQ?

From the pics I've seen of your room it looks to be rather lush with

reverb so you're going to suffer extra from the nonlinear power

response of your altec top-end configuration.

An alternative to the constant directivity setup (flat power response)

would be to implement a lot of acoustical treatment and soak up the

frequencies below ~6kHz where you've got a lot of beaming happening.

Open cell foam at the early reflection points would be a great place to

start.

If you had access to an ETF, you should be able to see the effects of

the on-axis and off-axis response at your listening position, which

would clarify the non-linear power response issue and give you an idea

of the most feasible solution to the problem.

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If you're willing to put an EQ in your system, then perhaps you should

consider a constant directivity horn with the typical CD EQ?

An alternative to the constant directivity setup (flat power response)

would be to implement a lot of acoustical treatment and soak up the

frequencies below ~6kHz where you've got a lot of beaming happening.

Open cell foam at the early reflection points would be a great place to

start.

If you had access to an ETF, you should be able to see the effects of

the on-axis and off-axis response at your listening position, which

would clarify the non-linear power response issue and give you an idea

of the most feasible solution to the problem.

I've had CD horns (K-600 and Pyle Pro horn) and didn't like either one, so why would I want to go back to another one?

I thought beaming occurred at higher frequencies, not lower. Not to mention that when I listen to my stereo, I'm sitting right in the middle, so if there is any beaming going on, it isn't affecting me anyway.

"most feasible solution to the problem"

I was unaware of any problem I was having other than the rolled off top end. You've seen the plots I've posted before of my system. You know how flat it can be, so if anything, the room is helping more than it's hurting.

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BS

Yes, you are rather full of "that", aren't you?

Who the hell are you to tell me what I do and don't hear on my own damn system?!

Oh, I forgot... You have calibration mics and occiliscopes for ears. Stupid me. Posted Image

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