Jbl C-50sm

[Dennis Albro]

I have a pair of JBL C-50SM's. They are in excellent, all original condition. I would like to use these as soffitt mounted studio monitors. Would it be a good idea to add 2405's with an Ashly SC-88 crossover and tri-amp. I would like some expert opinions before I cut holes in the cabinets.

[grumpy]

Hi Dennis. I offer no expert opinion.

I would ask a few questions though, as your seemingly simple question
is bursting full of unanswered details:

Are the systems of value to you monetarily?
(why modify excellent, all original bits of history?)

Do you truly feel they are still valid as "studio monitors"?
and useful enough to go to the expense of soffit fitting/mounting?
and would you be using them as such?

Would bringing them up to essentially 4333 (not -A) specs
change the answer to any of the above questions? (i.e., adding 2405)

Would adding a 25+ year old 12dB/octave generic crossover and
adding independent amplifiers (discarding the passive crossover) be
an improvement over a component-specific, modernized, bi-amp-able
passive design?

My non-expert -opinion- would be to save and enjoy the monitors if
you like such nostalgia, or sell them to someone who does, and invest in
modern tools for the studio.

Welcome aboard.

[bigyank]

Welcome aboard. For historical purposes, how about some detailed pics.

Yank

[toddalin]

Assuming that yours are like mine were, they have the S7 load with the LE15 and LE85 on the short horn with a 500 Hz xover. In reality, the short horn does not like to play well down to 500 Hz leaving a gap in this region that may or may not disturb you. The longer horn (used on the L300) will fit within the cabinet and get you a little closer to that 500 Hz point. Alternatively, an 800-1,200 Hz x-over would be better suited to the horn, but the woofer may not reach that high so well.

As for adding the 2405, do you feel that the HF is lacking with the existing setup?

You may be able to just add some high frequency compensation and push the highs up a bit further saving you from cutting up the cabinets and investing $400+ in a pair of vintage tweeters.

You may want to simply try putting a 1 mfd non-polarized capacitor between the positive speaker input and the positive horn output on the crossover as a high frequency bypass. This may make the highs too bright and you may end up putting a resistor in series with the capacitor to tone down this brightness some.

This would cost next to nothing to try, won't hurt anything, and may provide you with what you are looking (listening) for at minimal cost with no long term deleterous effects to any vintage equipment.

[Dennis Albro]

Hi all and Thank You for the welcome.
I got the C-50’s in 1972 and they were free from a JBL rep in LA. The sound company (ShowCo / Dallas) we were using bought a ton of components from JBL. First, let me say that if these are of any historical value or are rare, I will not alter them. It’s a shame so many are being ‘Parted Out’. The reason I don’t put a high value on them is that I also have ...Altec 14’s, 19’s, 9844A’s & Valienca’s and JBL 4311’s, 4312’s, 4699B’s and speakers and drivers from two L-65’s. I am building an analog studio and the C-50’s and the Altec 19’s will be soffit mounted. However, they will be mounted with no damage to the cabinets. I love the JBL sound and the C-50’s, 4320’s and 4333’s were used in some of the best studios in the 60’s / 70’s. Doing live sound at 400+ concerts has attenuated my HF hearing. That is why I want to add the 2405. It’s not what I hear, it’s what I feel. I have used the Ashly 88 and I believe I can tune the control room better than with a passive xover. Most of you know much more than I do. I am just an old roadie. Do your think any of the others would be a better choice? What other options do I have to recreate a vintage control room.? Any comments/recommendations will be greatly appreciated. My web site is http://albroanalogaudio.wordpress.com

[Dennis Albro]

I forgot to mention .. The Ashly will also give me a Sub out. I will be installing a JBL 2241 in a built-in enclosure.

[louped garouv]

... I believe I can tune the control room better than with a passive xover. Most of you know much more than I do. I am just an old roadie. ...

don't discount your experience....
we all start somewhere, and hopefully progress from there...

I personally like active crossovers also, as I am not yet a magician/mad scientist wrt passive crossover design/building


PS welcome aboard!

[spkrman57]

I prefer passive crossovers also, but for me it is because I don't have a tubed electronic crossover and I have a all tube system(okay cd player is SS, but has tube buffered output).

When I have used electronic crossovers in the past, the main one used was a Rane AC-22 (2-way). I liked what it did, and it had all the features I liked and needed, but I could hear the SS sound coming through.

I think only the "die-hard" tube fans with horns (or very high efficiency speaker systems) will understand what I mean by that.

Ron sends...