My system-need comments/recommendations!

[spkrman57]

When putting together my Edgarhorn system I had drivers in mind that were close, but not the best recommended by Bruce Edgar.

I chose a JBL 2205A for the midbass horn(because I already had a pair). I have since installed the E130/2225 reconed drivers from Mike B. since the Qes was close to ideal for that purpose, not to mention the 2205A is questionable in my mind(magnet lost strength???), and the E130/2225 is ferrite and eliminates the issues there. It is a shame as my 2205A's have cones that look mint, but I have doubts about the midrange response(seems lacking).

Anyways, on to the midrange horn driver selection. I had a pair of Altec 288C's with 16 ohm aluminum diaphrams. (Yes, already on hand). Bruce's recommendation called for a JBL 2441 driver, but unable to locate any without selling 1st born, the 288 pulled duty.

I am wondering if the latest JBL 2" driver(at least to my knowledge) the 2446 is comparable to the 2441??? The Altec 288C is alnico and going to a JBL ferrite seems like a good idea. The 2441's are no longer in production to the best of my knowledge, so what would be the next best available 2" driver to the 2441???

On top of this I bought a pair of Fane ST5022 horn tweeters. While they are probably better than my JBL 075's, I want to use the 075's as I like what they do with my D123's and N2400 crossover that sees part-time duty in the living room. I have heard they shout and beam, but I think they could be used well if crossed over at the right frequency. Note: it is a 16 ohm driver vs the Fane ST5022 which is 8 ohms.

The crossover as it stands currently is a 2.5mh on the midbass horn driver, 40 ufd oil cap and 8 ohm L-pad (parallel 16 ohm resistor across the 288) for the midrange horn(500hz @ 8 ohm), and a 1 ufd cap for the horn tweeter.

I have noticed the time and R & D JBL put in to some of their crossovers. I always thought the minimalist approach was best in speaker crossover design, but after reading many old posts on crossovers and such(and trying to understand Giskard and his explanations, some of which are way over my head). I have come to the conclusion that if my wallet were not so empty, JBL could design a better crossover for my Edgarhorn. With my means being so limited, I think I will have to stay with the 1st order crossover for now.

The bottom end of this system will be Rane AC22 electronic crossover for 80hz down(midbass horn bottom limit) fed off 2nd pre-amp output, and then run into(for now at least) Sansui AU-7900 SS integrated that was just repaired and modded(75WPC) for stereo sub duty into a pair of 2242's that are coming soon.

The Edgarhorn system will be powered by Yamamoto 45 SET amp(2 WPC), DeHavilland "Verve" preamp, and Audio Note cd player with "tube buffered output".

As you can see, I am much into tubed audio gear leaving SS for sub-duty only.


So my questions are related to the midrange compression driver selection(replacing Altec 288 with JBL 2" driver???) , replacing Fane ST5022 tweeter with JBL 075(or keep the Fane???), and last but not least, looking into the possibility of a different crossover scheme(not sure if that would help - or could I afford it???)


At the current time, the system is apart and in the spare bedroom, but I have screwed around long enough and it is time to put the BIG system back together again.

I don't mind criticism of my decisions here, you will not hurt my feelings, so don't be bashfull!!!

Last note: Living room size is 12' x 16' w/8' ceiling. When time permits, and I get rid of my collection of audio pieces and orphan chassis's) from the basement, I can relocate there to a room size of 13' x 21' w/8' ceilings. You can tell I don't have the ideal house for the audio system I have, but I will accept the limitations and live with it. I don't foresee me getting rich anytime soon!!!


Thanks, Ron

[Robh3606]

Hello Ron

I was under the impression you could take a 2445 and install the aluminum 2440 or 2441 diaphram. That would give you a more readilly available core with new diaphrams.

Rob

[spkrman57]

If I had a pair of cores from 2445(and they were suitable), I would still need the aluminum diaphrams and a reputable service tech to do the job.

It's a shame that JBL did not have a shop like "Great Plains" where we could buy re-conditioned drivers that were up to spec like Bill H does.

I wonder what the cost of getting a pair of 2441(or clones) up to spec would run? Now you know why I am using the Altec 288's, and they were not that cheap either.

Maybe someone reading this thread will come up with finished product answers. I am surprised that Bruce Edgar did not have any suitable "current" JBL 2" drivers for use on his 350hz round tractix horns???

Ron

[Earl K]

Hi Ron,

I don't mind criticism of my decisions here, you will not hurt my feelings, so don't be bashfull!!!

I'll elaborate more this evening but briefly ;

(i) I feel its a grave mistake to apply the good Dr. E's "fixes" to Altec drivers. His DC rated oilers and conjugate resistors are applicable for JBL 4" diaphragms. Much less so for Altec 288 drivers .

(ii) If I was you I'd completely redo you horn circuit from scratch .

(iii) Toss that 16ohm conjugate - not needed / adds way too much damping .

(iv) As a consequence buy the correct 16 ohm L-Pad . Better yet , go with fixed a resistor Lpad .

(v) Dump your current capacitor. You didn't say if it was PIO - but that's my assumption . Go with MPP in oil . Even straight metallized polypropylene in oil needs a lot of bypassing to release the upper transients. I wouldn't listen to a 288 with any more than 50 % of the capacitance coming from an oil damped capacitor.


Overall : I look at the choices you've made for your 288s and conclude they should be incredibly "dull" sounding ( even with tubes ). Those choices would be much more applicable to JBLs' large format drivers which to my ears are very , very, underdamped. The good Dr. has added a lot of circuit damping to conteract this standard JBL characteristic. Altec 288s , right off the shelf, sound to my ears to be "critically" damped. All the circuit fixes that you've applied makes that Altec driver type, sound very, very, "over-damped" ( IME ).

- Release its' dynamics and then take another listen before capitulating to the Dr.s' format ( its' cheaper and more educational ) .

Just My Opinion

PS : You've essentially been "Brake-Torquing" that horn setup and then wondering why the babes aren't riding with you .

[spkrman57]

Where would you get those caps you are referring to below?

" (v) Dump your current capacitor. You didn't say if it was PIO - but that's my assumption . Go with MPP in oil . Even straight metallized polypropylene in oil needs a lot of bypassing to release the upper transients. I wouldn't listen to a 288 with any more than 50 % of the capacitance coming from an oil damped capacitor"



Would you have a better idea for crossover than the 1st order I currently using? Bruce did mention that the Altec 288 driver was not on his favorite list. My problem is that after buying up the wood horns and a few drivers, my wallet is crying for mercy. Are you saying that the 288's could sound better with different crossover topology?

I like the info you are giving, just give me time to digest it all and see what I can afford as far as changes to the system.

Ron

[Earl K]

Ron

- I'll get back to you later today.

- I've gone shopping.

[spkrman57]

Earl,
For reference later when you have time, I have the following parts to play with:

Midbass horn/hyperbolic-exponential 80hz cutoff
E130/2225H (8 ohm-driver for horn above
laminated core 2.5mh for above(nice lams and large wire guage)

Altec 288C(16 ohm aluminum diaphram)
350hz tractix round wooden horn(has 1.5" thick adapter for Altec 288 vice JBL 2241)
40 ufd oil cap (motor cap - PIO ???)

Fane ST5022 horn tweeter (8 ohms)
JBL 075 (16 ohm) (my preference just for the cool JBL factor)
1 ufd oil cap (same as above - unkn???)

As I have no real testing gear,
(woofer tester from PE is not good for horn drivers and is used for rudimentary testing of cone drivers anyways-nice cheap toy though for unknown drivers),

and I don't have the knowledge like our resident guru "Giskard" and others to design the crossover is why I am posting here now.

If you have a crossover design in mind and could draw it out here on forum, I would love to see what other options might be available to me.

Thanks for your time Earl, it is appreciated.

Ron

[John]

For what it's worth I have been told by a few people that they have tried both the JBL2441 and Altec 288 and they say they prefer the 288 Altec.

[4313B]

That's only because they want to be contrary.
Slap them.

[Mr. Widget]

The 288 has a loyal following.... but then so do some terrible sounding speakers. I know next to nothing about the Altec 288, but I do respect the JBL 2441.

One thing I've discovered is that using adapters is almost never the way to go. If you have a 1.5" horn you will get the best results with a 1.5" driver and a 2" horn will sound best with a 2" driver. A horn is an acoustic transformer and if you use an adapter you won't get the proper loading for the driver. Just because the adapters are made and they seem to work doesn't make them the best solution. Typically they are a stop gap... they will work, but compared to properly mated horns and drivers they just don't cut it.

Widget

[Titanium Dome]

One thing I've discovered is that using adapters is almost never the way to go. If you have a 1.5" horn you will get the best results with a 1.5" driver and a 2" horn will sound best with a 2" driver. A horn is an acoustic transformer and if you use an adapter you won't get the proper loading for the driver. Just because the adapters are made and they seem to work doesn't make them the best solution. Typically they are a stop gap... they will work, but compared to properly mated horns and drivers they just don't cut it.

Widget

I couldn't have said it better, so I didn't.

[Earl K]

Well Ron, the jury has spoken - you better just go buy the 2441(s) and get back onto Dr. E.s' path of enlightenment

[spkrman57]

Well, if the 2441 is the driver to go for, now is the task of how to get them without a 2nd mortgage. Anyone have any ideas and sources on the 2441's???

Or, is there a current JBL driver for 2" that would work as well?


More comments/opinions welcome!

Ron

[mikebake]

I will say this; given its sound and its stature and its resale value, owning 2441's shouldn't be much risk if you ever decide to move em out down the road.

Well, if the 2441 is the driver to go for, now is the task of how to get them without a 2nd mortgage. Anyone have any ideas and sources on the 2441's???

Or, is there a current JBL driver for 2" that would work as well?


More comments/opinions welcome!

Ron

[spkrman57]

Okay, who has a decent source for a pair of 2441's???

Ron