Piezos require a crossover, because without an xover they sound harsh and they will break. The crystal will get cracks and will loose sensitivity. The impedance of a piezo speaker is a small capacitance. Putting an 8 Ohm resistor parallel to the piezo will turn it into an almost perfect 8 Ohm load.Originally Posted by Mr. Widget
Piezo tweeters... that takes me back.... Widget
Ruediger
I have a DIY 4350, I am continuously amazed at the dynamic and super transparent sound of this vintage design, we are after all talking about 1970 technology but I would not trade this for anything else, although the design goes back to analog era I can not think of any speaker that can reproduce uncompressed digital recordings with such clarity and dynamics.
Good recordings sound spectacular on this monitor, crappy recordings sound horrible, I guess its garbage in garbage out design principle.
More recently I started searching for a smaller JBL’s for my second system, I have been searching for a pair of 4430’s for some years with no luck, but then one real clean pair became available in Houston so I packed a few CD’s and went for a demonstration, I had high hopes based on endless praise for these newer generation of two way JBL’s, but what a disappointment, I guess being used to the high frequency response of my 4350’s the 4430’s really sounded dull, the high frequencies were just not there, well had to give up on these after dreaming for these for over two years.
What exactly was JBL trying to accomplish with their newer 44xx series? Was this supposed to be an improvement over 43xx series? Not to my ears, not even close!
Vahe
The bi-radial horns are designed to provide broader, more consistent "coverage" at the expense of the narrower, beamy high frequency flat output of the older exponential horns. They require significant equalization in the upper treble in order to achieve equivalent flat output response. Intended mainly for pro use. But, in terms of hi fi, they sound forced, dull . . . like you said! There is a technical paper somewhere in the data base here re the engineering development process. I experimented with a 2382A for about a year but never could make it "sound." Kind of like when you can't find the right trumpet mouthpiece. Come to think of it, never saw a brass instrument with a bi-radial bell. There is probably a message here! Mike
With the 4350 as reference Im not surprised that you found the 4430 lacking. The 2440 and 2405 are superb drivers and with the proper xo they work wonders. If you are more into vintage, you might like the L300 more than the 4430 for a smaller system.
/Mostly
Hey guys, thanks for reacting.
Vahe: post a picture of your DIY 4350, we like to see it.
Back to my 4344's.
I will bi-amp the low's and I'm thinking of keeping the passive x-over external so I don't have to open the 2235's everytime during the tests and fine-tuning of the x-overs.
So I bought 16 terminals, two pieces of high-voltage insulation board (10mm Pertinax) and made a layout. Right and left will be different.
Did a test cut-out with a 30mm piece mdf.
Proper high-end project!
I will try to find that topic on LH where someone has built external passive networks for his 4344's!
As far as I remember he also had fancy wooden boxes for them.
[QUOTE=JBLP;355440]Hey guys, thanks for reacting.
Vahe: post a picture of your DIY 4350, we like to see it.
Will try, not sure how to load images but let's see if it works
Vahe
Hey Vahe: Impressed by your serious DIY 4350, thanks for sharing.
All 4350A drivers what I can see. Did you also do the network?
So you changed the layout of the front. To fit the bookcase, or came the bookcase later?
I can imagine they sound like you described earlier.......
Thanks man!
Paul
Building your house around the speakers
Paul, do you know the model number of your Beyma horns? I hope to receive "2 2441 drivers soon as upgrade from the "1 2421B but I need the 2311 type horn which is much shorter. I can't find it anywhere in the Benelux so I wonder if Beyma has made a copy suitable for "2.
[QUOTE=Vahe Sahakian;355641]Checked the picture several times this day, because something is wrong......Hey guys, thanks for reacting.
Vahe: post a picture of your DIY 4350, we like to see it.
Will try, not sure how to load images but let's see if it works
Vahe
Now I know....
All the leads to the voice coils are pointing upwards.....
[QUOTE=ds23man;355686]The beauty of the MA-15 woofer clamps is that you can rotate the woofers to prevent sagging. I used to go a few months with VC leads up and then a few with them down. I still would, but I don't have speakers with clamps.
Checked the picture several times this day, because something is wrong......
Now I know....
All the leads to the voice coils are pointing upwards.....
Widget
[QUOTE=ds23man;355686]Those 2235’s were all recently re-coned with original JBL parts, I believe what you are seeing in that image is the image distortion caused by the wide angle camera lens. I re-examined all the cone drivers and everything is dead centered, there is absolutely no sagging.
Checked the picture several times this day, because something is wrong......
Now I know....
All the leads to the voice coils are pointing upwards.....
Vahe
4350
Vahe
Nice looking speakers, I bet you enjoy them.
What do you listen to?
What do you drive them with?
Widget is not suggesting that your drivers are sagging he is saying that he used to rotate his drivers regularly to prevent sagging which might happen if you left them in the same position for a long time.
My 2220s didn't sag in over 20 years but then they have a much lighter cone and stiffer suspension than the 2235s.
I would like to ask why you placed the horn/lens combo and the 2405s off to one side?
It looks like there is enough space in the cabinet to place everything in a vertical line, would that not produce a more stable stereo sound stage?
How does it sound with the speakers cabinets placed as they are in a bookshelf as opposed to further into the room?
JBLP/Martin2395
I was wondering why you used Beyma horns as opposed to JBL?
Would it not be better to keep it all JBL?
I really like my new 2370s with the 2425s.
To me they are much cleaner than the my old Altec 808-8As/811Bs.
This is possibly the diaphragms, maybe I'll try the JBL diaphragms in the Altecs and vice versa.
Does anybody know if OEM Altec diaphragms are still available?
Where did you get this Pertinax?
I can only find it in 0.5mm thickness and think it would be too flexible.
Where did you get your binding posts?
Looking at your drawings it appears you have a drafting/engineering background.
My Dad did and always produced similar drawings of any project, he never made any speakers though.
I always try to as it helps precision but I have no training in those fields.
Mr. Widget
I had a machinist friend make polished aluminum clamps for me when I made my speakers.
If I make some more I will countersink the drivers flush with the front surface and will use simpler flat clamps.
Even steel could be used and fabricated with simple power tools, I prefer aluminum as it doesn't rust and rust is dangerous to speakers with open voice coils (most horns and all vented bass drivers).
Steel could be painted or powder coated though.
I prefer to just polish the aluminum.
I listened to Zooey Deschanel singing the Carpenters "Yesterday Once More" that I found on this forum. (nice voice but very poor background music and levels set too high for dynamic range of her voice)
Then I listened to Karen Carpenter singing it on vinyl on my JBLs and was really impressed with the performance and recording quality.
Both Karen and Richard were very good at what they did.
You might not like the Carpenters but will have to admit that very few recordings match that level of quality and professionalism.
Nice looking speakers, I bet you enjoy them.
What do you listen to?
What do you drive them with?
Widget is not suggesting that your drivers are sagging he is saying that he used to rotate his drivers regularly to prevent sagging which might happen if you left them in the same position for a long time.
My 2220s didn't sag in over 20 years but then they have a much lighter cone and stiffer suspension than the 2235s.
I would like to ask why you placed the horn/lens combo and the 2405s off to one side?
It looks like there is enough space in the cabinet to place everything in a vertical line, would that not produce a more stable stereo sound stage?
How does it sound with the speakers cabinets placed as they are in a bookshelf as opposed to further into the room?
Since you asked;
First and foremost I did not care much for the horizontal setup of the originals, those are very difficult to position in home music room settings, JBL used the same horizontal ergonomics with the next generation 4435 and all the way up the their Everest. In all residential setups that I have seen with 4350/4355, 4434 or the Everest these monster sit low on the floor and that is the worst possible way to utilize these speakers, I consider a distance of about 2’ an absolute minimum from woofers to the floor.
Mine uses all stock components including 3107 networks, the active crossover is JBL 5234A, have two of those, one with 250Hz card and another with 290Hz card, I have tried both and can not really tell any difference. There was a discussion here on this website a while back on charge coupled crossovers for these speakers, I got on a little late, I did send an email to the person making these to see if I could buy a set, never got a reply from him.
As for why I did not place everything on a vertical line, that would increase the height too much, and given the size and volume of the music room I do not think that such arrangement would make much difference, in their present configuration the tops of the cabinet is 64” from the floor.
I will try to load another photo of the stereo cabinet photographed from my normal listening position which is roughly 12-14 feet from the JBL’s. You can pretty much see how large the space is and how tiny these JBL monsters appear in that space.
The “bookshelf” is in fact a 24” deep cabinet, it is 8’ high and 17’ wide. The cabinet was constructed to house all my stereo junk including the JBL’s, I did all the work all by myself, I am an architect by profession. This is my music room, it is isolated from the rest of the house, no TV in this room, strictly music.
The rest of the room has acoustic wall treatment, all the books and other items stacked up in the stereo cabinet help the room acoustics, there are no echoes from the walls and the sound stage is superb, you can “see” where each instrument is located.
These DIY’s were built a long time ago, I am primarily into classical and some jazz, 100% acoustic instruments, I have a large collection of LP’s, even larger collection of RBCD’s but now I am pretty much into SACD, well recorded SACD’s do sound noticeably superior to CD’s on a wideband equipment.
The enclosure is made of ¾” birch plywood, the two separate 5 cu ft. low frequency enclosures have an additional ¾” dense particleboard liners laminated to the outer birch plywood. Throwing a punch at the side of the low frequency enclosures feels like hitting concrete, no resonance issues with this enclosure.
The downside of this is the weight, if I had to do it over again I would make the low and high ends in totally separate boxes.
These 4350’s have definitely good many strengths and also many weaknesses.
For reproducing pipe organ at full power these are ideal speakers, they produce very powerful and natural sound all the way down to about 28 Hz totally free of subwoofer style unnatural booming bass. The high resolution solo piano recordings, particularly reproducing the sound of Steinway D is one of the strengths of this system.
I use two vintage McIntosh 2205 power amps and also a Mac preamp, my music room is large, 18’ x 27’ with sloped high ceiling, the volume is roughly 6000 cu. ft. 20W per channel for each hi-low ends is the upper limit for the volume from my listening position, about 12 to 14 feet from speakers, that I can tolerate, above that the volume becomes dangerously loud.
And, although the design dates back to analog era, the way these 4350’s handles uncompressed orchestral recordings on SACD with all of the dynamic range is something that very few speakers can handle.
The extreme clarity does have its negatives, 4350 has killed the vinyl for me, classical music unlike rock/pop does have frequent very quiet whisper like musical passages, this is where all the surface noise, clicks and pops and high level of audio distortion that is the hallmark of the vinyl starts competing with the music, for vinyl I recommend B&W speakers, I have a pair of two way B&W’s that I use for vinyl, they do a better job of masking surface noise than JBL’s.
Garbage in, garbage out pretty much describes the sound of these larger 43xx series JBL’s.
Vahe
Vahe
Thanks for all that.
The first pic is kind of deceptive, this brings it all into perspective.
I thought the cabinet is tall enough for all the drivers in a vertical line, they need to be lowered and brought closer together.
I was also under the impression that drivers work better at crossover point if they are closer together vertically.
Why should a bass driver be at least 2' from the floor? mine are much lower and seem to work pretty good to me.
I listen mostly to 60s and 70s Prog rock but also later stuff from The Police, Dire Straits The Floyd Marillion etc.
Pretty much all on vinyl.
Lots of open spaces in the stuff I listen to and I find my Nottingham Analogue is very quiet if the record is well taken care of.
It also sounds very clean and natural.
I still have Led Zeppelin II that I bought new back in the day and it sounds fine.
Vertical tracking height adjustment is very important for low noise.
Bloys
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