MC252 with JBL 4429

McTwins

Active Member
Hallo!

I have recently bought a new pair of JBL 4429 and started with singel MC252 but took my brothers MC252 and connected it in Mono Bridged mode and it sure sounds nice:thmbsp:

I also have done some measurement at my listening position. The measurement is done with singel MC252. I will do a comparison between mono and singel MC252 but I doubt it will be a sigificant difference, maybe some SPL level changes. We will see...

:music:
 

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The speaker is rated at 200 watts, with 6 db peaks . So with your 252 capable close to 400 watt peaks and over 300 watts continuous, I'd be careful. Remember that the woofer is handling half the power and you maybe stressing that midrange.

The freq. resp. curve you measured reminded me of one Roger Russell's preferred curves for loud speaker systems. My curve is similar with about 3 db more output from 2k to 8 khz be fore rolling off. What is great is how smooth it is. The roll-off above 12KHZ will make for long term listening with out fatigue. 3 or 4 db rise on the treble control and 3 less on the bass and you would `have a near field response loved by some. I think its to analytcal my self. What you are going to have to figure out is where the best listening distance is, to get the right combination of direct sound from the speaker versus reflected sound from the room. But you are definitely on the right track. Are you measuring the speakers on or off axis? You could crank up the super tweeter up another 3 db as an experiment. Especially if you like close miked percussion, with out causing violin and brass over emphasis. I bet the speakers are fantastic with piano, acoustic guitar, banjo, and pipe organ. They may be a bit subdued for big massive choir and marginally recorded LP from way back when, but they should also allow you to listen with out being irritated if you use Shure or A-T cartridges.
 
I don't get that excited about speaker much any more but, man, those JBL's get the juices flowing.

I'm sure they will stand up and sing with all that great electronics oomph behind them.

Good job!

Cheers,

David
 
The speaker is rated at 200 watts, with 6 db peaks . So with your 252 capable close to 400 watt peaks and over 300 watts continuous, I'd be careful. Remember that the woofer is handling half the power and you maybe stressing that midrange.

The freq. resp. curve you measured reminded me of one Roger Russell's preferred curves for loud speaker systems. My curve is similar with about 3 db more output from 2k to 8 khz be fore rolling off. What is great is how smooth it is. The roll-off above 12KHZ will make for long term listening with out fatigue. 3 or 4 db rise on the treble control and 3 less on the bass and you would `have a near field response loved by some. I think its to analytcal my self. What you are going to have to figure out is where the best listening distance is, to get the right combination of direct sound from the speaker versus reflected sound from the room. But you are definitely on the right track. Are you measuring the speakers on or off axis? You could crank up the super tweeter up another 3 db as an experiment. Especially if you like close miked percussion, with out causing violin and brass over emphasis. I bet the speakers are fantastic with piano, acoustic guitar, banjo, and pipe organ. They may be a bit subdued for big massive choir and marginally recorded LP from way back when, but they should also allow you to listen with out being irritated if you use Shure or A-T cartridges.

Hallo!

I don't see any problem with the power I put to those speakers, speakers are rated at 200Watts(RMS) at 6 Ohm nominal and to me, continuous power is around 400Watts with additional peaks at 800Watts. I am within those limits either I am running Singel or Mono. I'm not worried at all.

About the woofer's power, it seems that it can handle more power than what I put in to it....:yes:
http://www.audioheritage.org/vbulletin/showthread.php?21713-1200fe-8

I forgott to mention, with this measurement the mic is 6meters away at my listeningposition. The sound is good and it is not so critical where I sit due to my acoustically treated room. Remember, I don't use any sub.:D

I have been listening with all kinds of music and it all sounds good.
 
That's a great response for that distance! you have a very good room. YOU REALLY DON'T NEED A SUB! Your well extended to 30 HZ. At 6 meters you are sitting in the reverberant field/ I imagine your Dc is around 10 ft. Take your measurement mic while producing sound from one speaker and see how far from the speaker you can get before the 2khz octave stops dropping off and becomes constant in the room . If you are seated with in 1.5 times that distance with one speaker on then you are only losing about 5% of your ability to recognize consonants of speech. Of course when you add the second speaker the Dc will be shorter and your ability to understand will deteriorate. If your reverb time is short, you really have very acceptable room performance. That distance explains why your high frequency is dropping off above 12 khz, too. Speakers with a very flat response above 12khz, if you can hear that last octave, can be very irritating. And is why women sometimes won't listen to a system. I imagine your wife enjoys the system.

JBL makes very robust woofers and they have a sort of built mechanical limiter as did Gauss, EV, Altec Meyer etc, that a lot of home speaker manufactures don't use. Your woofers won't self destruct as easily as others, but the limiting is there and when you add more power the output just doesn't increase anymore. You 'll notice there is a tonal shift when you turn the sound level up and the bass won't have the transient response it had before you raised the level. Plus the mechanics of the middle ear will have kicked in long before limiting the dynamic range to your inner ear. Unless you have defeated the ear by taking stimulants or depressants. Guys drinking a lot booze at concerts and loud musical venues wonder why that have headaches, ears ringing and buzzing, and can't hear as well as when they were pre-teens. If your Dc is 10 ft. That means every where past that distance the 2khz octave should be constant. So if your speaker is 93 db 1 watt i meter. Then at 3 meters the out put at 1 watt is 85 db. With 100 watts that would mean 105 db 200 watts 108 db and with 400 watts 111 db if the speaker hasn't gone into self limiting. With a Mac 1 k speaker at 88 db, but dropping off a 3db with doubling of distance, That would mean 88 db 1 meter 1 watt and 83 db and there fore you would need 50% to 60% more power to get the same level of performance as your JBL's. You would need a 402 to get the same levels as with your single 252. I doubt a pair XR 200 could keep up with your JBLs on over all level out put. But The dreaded Klipschorn would only need about 25 watts. I know they don't sound as good as your JBL. But they are loud and efficient.
 
Hallo!

Thanks everyone for the kind words.:thmbsp:

Twiiii....I am running in mono as mention before, so I have 500Watts/speaker.

Yes, you are correct, both the response and the sound is good. I don't hear any fatiguing sound even if I play at high volumes. I understand about critical distance, but, I think that I am within the critical distance in my room due to we are talking about small room acoustics. Regarding the Reverberation Time, the T30 from the same measurement is around 0,3-0,4sec and even from 100Hz-8kHz. Without any porous absorbtion panels installed.

But of course, if we are comparing with the PRX600 series I have, it's a differen't animal. PRX is more suitable for this large room I have but the 4429 performs quite good consider them to be small box speakers.

I am happy either way.

Here is a picture and running at 65% at volume level from my C48 and it is around 500Watts on MC252 without clipping:banana: Picture is little bit bad, Sorry for this.

4429 is for soft and allround background music and PRX is if I really wan't to turn things up and party. But if I wan't I can always go upstairs and have perfect sound reproduction both acoustically and sound wise.:D

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Well I will have to say that room is really stacked for sound. At first appearance it would seem to be a little bright for my taste, but I'm sure you have that in control. As I examined the picture more closely to figure out if those were 275's or 2100''s I see absorbent material of some type over a vast majority of the surfaces. What is the lowest frequency your acoustical material is effective?
 
Well I will have to say that room is really stacked for sound. At first appearance it would seem to be a little bright for my taste, but I'm sure you have that in control. As I examined the picture more closely to figure out if those were 275's or 2100''s I see absorbent material of some type over a vast majority of the surfaces. What is the lowest frequency your acoustical material is effective?

Hallo!

On the contrary, the room looks bright but it is diffusion you see on the walls. The room treatment goes down to 25Hz-16kHz. It is temporal diffusion and the control of the early reflection that is important. The Varitunes Helmholtz resonators controls the modal distrubution of the room. Some DIY panel absorber.

Measurement of the room tells more:yes:

http://www.gearslutz.com/board/9664574-post182.html

Yes, it is MC275 in mono or singel MC252 for the mid/high and two Crown Macro-Tech MA5000i feeding the subs.
 
Yes, it is MC275 in mono or singel MC252 for the mid/high and two Crown Macro-Tech MA5000i feeding the subs.

How do you find the MA5000i on the subs? I have to admit I am not as fond of the MA5000i as I am of the 5002VZ I run on my subs......

There was something about the grounded bridge design of those Macro-tech 5002VZ amps which really works with my system....
I tried a MA5000i and thought it was OK but there was something missing.....
Of course I am using different speakers, so perhaps the synergy was wrong in my case.....

I like your room and system, Very nicely done!!.....:thmbsp:
 
How do you find the MA5000i on the subs? I have to admit I am not as fond of the MA5000i as I am of the 5002VZ I run on my subs......

There was something about the grounded bridge design of those Macro-tech 5002VZ amps which really works with my system....
I tried a MA5000i and thought it was OK but there was something missing.....
Of course I am using different speakers, so perhaps the synergy was wrong in my case.....

I like your room and system, Very nicely done!!.....:thmbsp:

Hi

Best for me to chime in here. I am really satisfied with the Crowns. They do a great job controlling my subs:thmbsp: I have my limiter set to 600Watts(RMS) and peak limiter to 138Volts on both the 15" and 18" woofer and input sens set at 32dB. Plenty of power here for my little space:music:

I know that the first amps was little bit less in power and was upgraded later to have more power. In 4Ohms load the power was at 2000Watts compared to mine which is 2500Watts. Not detrimental but diffrent non the less. I bet you had lot of power for your sub in any case:yes:

Do you remember what setting you had, like input sens and limiter power/peak, when trying the MAi?

The combination of amp and sub in this room is only giving me pleasure and I have nothing to complain about:D
 
McTwins - now that's a great looking set up. I bet it gets LOUD and sounds GREAT! Reminds me of the days when I used to run (4) MC2300s in my set-up. I did also play with MC2300s strapped on the bottoms (Cerwin Vega 18") and MC240s strapped mono on the tops (Altec 9846-8As). Man, all that was a ton of fun.

When are you inviting all of us AKers over for a listen?
 
I was visiting JBL website and checked out their transducer specs. All the pro woofers have any where from 3.7 to 4 db of compression at 600 watt input. with less than 1 db compression at -10 db. So If you like things very linear with the pro line less power is more. The DD series the compression is appox half the proline. So having multiple woofers is the only answer if you want to keep the distortion and compression down, again. So like McIntosh and Bozak, 4 12" woofers surpass 1 or 2 good 15" woofers all other things being equal.

One of my dreams would be having new Alnico Altec 604's from Great Plains audio being supplemented with 2 Altec 3156 built in to a wall, behind a perforated screen with the rear enclosure being another room. Then with a 3 channels of my 207s driving the 604's 6 channels driving the six 3156, and using the other 5 channels for 604's in small boxes as surround speakers. With a MX 121 processor and all the accessories. MVP 891 etc to finish things off. No big power, just enough. And no Subs. Of course having the room acoustically treated would be as important. That's where the great advancement in sound has taken place in my opinion. Acoustical treatment, analysis and installation makes the good system a superior one.
 
Hi

Best for me to chime in here. I am really satisfied with the Crowns. They do a great job controlling my subs:thmbsp: I have my limiter set to 600Watts(RMS) and peak limiter to 138Volts on both the 15" and 18" woofer and input sens set at 32dB. Plenty of power here for my little space:music:

I know that the first amps was little bit less in power and was upgraded later to have more power. In 4Ohms load the power was at 2000Watts compared to mine which is 2500Watts. Not detrimental but diffrent non the less. I bet you had lot of power for your sub in any case:yes:

Do you remember what setting you had, like input sens and limiter power/peak, when trying the MAi?

The combination of amp and sub in this room is only giving me pleasure and I have nothing to complain about:D

I had it set to 32db, which works for the gain structure of my system, I use an external processor/X-over with the limiting set up in that.....other than that, the amp was wide open.
I felt the Mi was good at higher levels, but I also do a lot of lower level listening too and I felt it wasn't performing as well as my Macro-tech 5002vz in this area....
But having said that, different speakers can make all the difference......I was never going to replace my 5002VZ, I was curious to see if there was a difference....
Really, they are both great amplifiers, and you cant go wrong with either one at the end if the day.....
 
Hallo!

I have recently bought a new pair of JBL 4429 and started with singel MC252 but took my brothers MC252 and connected it in Mono Bridged mode and it sure sounds nice:thmbsp:

I also have done some measurement at my listening position. The measurement is done with singel MC252. I will do a comparison between mono and singel MC252 but I doubt it will be a sigificant difference, maybe some SPL level changes. We will see...

:music:

Personally, I'm a fan of the 3D glass amps. I think they are all beautiful.
 
Personally, I'm a fan of the 3D glass amps. I think they are all beautiful.

I agree. I've had flat glass (MC7270) and the 3D glass (MC252). I'll go for the 3D look every time. If I had the space and cash, the MC501's would be my choice of amp. I know the MC252 sounds almost identical but the bigger meters are cool.
 
Personally, I'm a fan of the 3D glass amps. I think they are all beautiful.

I agree. I've had flat glass (MC7270) and the 3D glass (MC252). I'll go for the 3D look every time. If I had the space and cash, the MC501's would be my choice of amp. I know the MC252 sounds almost identical but the bigger meters are cool.

I like also the 3D glass:thmbsp: MC501 is nice amp as well. I like the possibility of the older Mc like MC252 where on can connect them in mono or stereo. If one amp is going into faliure there is the possibility to use one amp in stereo.
 
I had the latest version of the 275 for three weeks and a 302 for 2.5 months while my 252 was at Mcintosh. I thought the 252 had a problem because it would overheat and shutdown at 1/3 1/2 power but the four 2 1/4 in fans I placed under the heatsinks took care of that.I much! prefer the speaker terminals of the 252,1/2 in glass,shallow chassis depth and I like how all the connections are facing up on the back.
 
I could barely fit my 12 gauge speaker wire into the 275,302 and with the 252 I can easily bi-wire my RF-II's.It was just done because I had the extra wire and looks allright.One thing I like about the 252 is that the stainless chassis runs straight into the front end caps without being devided by the black cover behind the front panel/glass.
 
Hallo!

I hope it is OK to link from LH so I don't need to rewrite everything again. I have done some measurements between bi-amp and mono bridged mode.

http://www.audioheritage.org/vbulletin/showthread.php?35547-My-new-JBL-4429&p=362345&viewfull=1#post362345

And here between 4 ohm and 8 ohm tap on my MC252 mono bridged mode.

http://www.audioheritage.org/vbulletin/showthread.php?35547-My-new-JBL-4429&p=362632&viewfull=1#post362632

The interesting thing is that with the pink noise thru my system it shows the same meter level between 4 and 8 ohm tap. I understand that it must be either voltage or current that is changing inside the amplifier due to the changes seen in the measurements. I have done some listening between these two taps connected and it is hard to say what sounds best.

I'm also bi-wiring the speakers in mono bridged mode.

I have talked to the designer of the JBL 4429 and it is 4 ohm minimum impedance on both the Woofer and HF/UHF. Nominal is 6 ohm according to specs.

The question is,

What is really happening inside the amplifier?
Why the higher SPL level in my measurements between bi-amp and mono? Why the changes in level in my measurements between 4 and 8 ohm tap?

My "guess" for the increase in SPL level has to do that it changes the input signal (XLR) between these Mono combination. I lookt at the Service Manual for the MC252.

What do you guy's say?
 
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