PDA

View Full Version : Jbl Mi 632 Info???



AFF
08-31-2009, 07:42 PM
Okay I searched everywhere and found only one PDF from JBL.com and I am in need of just a little help.

I have some JBL MI 632 cabinets that I purchased from my dad a few years ago. I can only determine they are MI 632's. Currently they are sitting in my lead guitarist loft because we don't have room to store them in my garage or use them for practice. I have used them quite a few time for live gigs but I feel like I did not get there full potential. They are relatively lightweight for their sound output.

The info I have from JBL's vintage site is that they are 150w/300w 2 way speakers. Looking at them I see what I SWEAR is an 18" woofer and a horn driver and two square ported holes near the top beside the horn. The 18" (even though JBL says it is a 15") is recessed with a metal mesh grill cover. The wood feels like a rough MDF or partical board ...might explain the lighter weight. Covered in a charcoal gray tolex of some sorts with square JBL labeled plastic corner pieces. Here is where I get lost ... it has square metal handles that say MR Series on the grip AND the input is : (2) 1/4" with a two or three way switch that is for high, low, mid range setting. I saw a few pictures of these cabs with a pot of some sort to dial in the freq??? unsure.

I don't know a lot about these beauties so any info is helpful and I will be very thankful.

I will get some pictures of them hopefully this weekend so you can look them over. I have yet to find a good picture of them on the internet. I think they are from the 80's according to the JBL website but they look like the modern cabs today. Well I guess they favor the MRs and the SRs.

By the way if you know the best way to operate these I am listening.
I currently have a Soundtech MegaMix10 900watts, Peavey Unity 1200 unpowered, 1200 watt power amp, JBL TR225 Mains ( i know most people hate these but they work so well for our music : metal) 15" 2 way custom cab main/monitors, 4 15" wedge monitors. I love JBL and Soundtech and I have managed to marry the system quite well together for some great sounding gigs and I am looking or should I say needing to include the MI 632's for some of our larger gigs now but I am not sure yet if that would be best. I used to use the MI's or TR's and they sounded about equal to both their volumes and quailty.

Thank You for you help in advance.

AFF

subwoof
09-01-2009, 05:28 AM
they are the very first gen MI stuff from crown after the cabaret line ended. 15 / horn. they made a flat front and an angle front.

flake board, smaller voice coils and lower power speakers / crossovers meant for the inexpensive PA / small club use. the recone / repair parts for those are very expensive and some are NLA.

go bigger - and stay away from the TR type stuff - it's even worse.


Find some old SR(A) or SRX speakers that have the newer neutrik connections.

sub

AFF
09-01-2009, 10:27 AM
they are the very first gen MI stuff from crown after the cabaret line ended. 15 / horn. they made a flat front and an angle front.

flake board, smaller voice coils and lower power speakers / crossovers meant for the inexpensive PA / small club use. the recone / repair parts for those are very expensive and some are NLA.

go bigger - and stay away from the TR type stuff - it's even worse.


Find some old SR(A) or SRX speakers that have the newer neutrik connections.

sub

Cool. Thanks for some more info on these. I actually already have a set of the TR225 speaker cabinets. Maybe I have listened to music too loud for too long but they sound good to me. I don't know as much as most here but at least they were good for the money that I paid for them.

By the way do you know what exactly the switch on the back of the MI's does? I am guessing it is an adjustable crossover of some sorts. I mean should I hear a difference in sound higher freq or lower freq? I thought about placing these under the TR's that I have and running them possible on seperate channel outputs ( especially since I learned that they max out at 300watts. and the TR's are at or over 1000watts). Are these MI's capable of decent bass response ... well I guess I am asking if I would be risking it pushing a Bass Guitar, Miked Kick Drum and Toms, and or Two Guitar Cabs miked. We play Metal and our music is a little on the heavy, loud, and Low Freq range level. I guess they would really be used for helping the TR's throw the sound out there a little better. We play larger venues sometimes and some have good accoustics and some have the worst possible so a little extra output can mean a lot.

The TR's have also compared well against a set of Carvins and Peaveys. Maybe I should pop mine open and see if they have been modified or upgraded :) That would be nice.

I found a decent amount of info on the TR's and I know a lot of people hate them. The Mi's that I have are the hardest to find anything about. This has been about the most info I have found. Thank you so much for the info and I am still lookoing for more if anyone runs across more info.

Thanks
AFF

AFF
09-01-2009, 10:43 AM
I forgot to include this question. Aside from the SR and MR lines what speakers do you think I should be looking for to replace the ones I have?

I am the vocalist so the PA gets left up to me not only to purchase but for most of it's use. I have thought about upgrading but I always thought about buying another power amp and another set of TR's. We play large areas and we often get very loud. My guitarists like to drive their Tube Amps very hard for that "perfect tone". So the PA is often run at high volumes to keep up as well. I am asking mostly because I love JBL and I would like to stay with the JBL lines but I guess I am not too sure what would suit our needs to the best. We don't have a true dealer around here so I can't test a lot of gear ... we have a Peavey dealer on every corner but good luck finding a JBL dealer with enough stock and a place where they are willing to allow you to truly test the equipment. This has been the best place that I stumbled upon for the info I am looking for.

Thanks
AFF

Fred Sanford
09-01-2009, 11:55 AM
By the way do you know what exactly the switch on the back of the MI's does? I am guessing it is an adjustable crossover of some sorts. I mean should I hear a difference in sound higher freq or lower freq? I thought about placing these under the TR's that I have and running them possible on seperate channel outputs ( especially since I learned that they max out at 300watts. and the TR's are at or over 1000watts). Thanks
AFF

The TR225s are rated for ~450W continuous. They're essentially 1" driver EON horns with two 3" voice coil Eminence 15"s. Mine have been absolutely babied, and they're falling apart- the baffle boards came loose & needed to be pinned & glued back in, and the cabinet bottoms & sides swelled up like sponges when they were near (not even in contact with) a damp floor. They get pretty loud with low power, but I wouldn't say that they ever sounded good. Mine came to me pretty much for free, so I'm OK with them for now as vocal monitors in a rehearsal space. I'd never gig with them, but I've done some outdoor charity DJ events with them- the horns didn't quite cut it, but I didn't care much.

The MI's switch probably lowers the output of the high freq horn, you should hear the volume from that horn change with switch positions.

je

mech986
09-01-2009, 01:05 PM
The schematic and service info below, no indication there was any switch in the crossover originally, may have had it added by a previous owner?

The OEM driver is a 15" driver, you should be able to access it from the rear panel to verify what is installed currently, should be the MI-15. If an 18" is in there, it's not nearly suited for that type of cabinet and size.

http://www.jblproservice.com/pdf/MI-Series/MI-632.pdf

http://www.lansingheritage.org/images/jbl/catalogs/1986_pro/b8.jpg

AFF
09-01-2009, 09:10 PM
Thank you so much for the info. I am getting some great feedback on this topic!

Thanks
AFF

BMWCCA
09-01-2009, 09:43 PM
. . . no indication there was any switch in the crossover originally . . . Sure looks like a three-way switch in the photo of the crossover in the "powerpack" which one might assume is the same as the crossover in the 632. :dont-know

boputnam
09-01-2009, 10:41 PM
I forgot to include this question. Aside from the SR and MR lines what speakers do you think I should be looking for to replace the ones I have?sub's got it...


...go bigger. Find some old SR(A) or SRX speakers that have the newer neutrik connections....but that is if you are happy with your powered mixer and want to stay passive.

If not, and you are sleeping on a small pile of cash, the VP-series (http://www.jblpro.com/catalog/general/ProductFamily.aspx?FId=16&MID=2) is pretty damned impressive. The on-board DSP's are finely tuned - you would be really pleased with their use, and you can upgrade to an unpowered mixer. :) Since these are powered, you can slowly migrate yourself over to them - for example, even one wedge at a time.

Start with some VP-series mains, and let the rest fall into place.

mech986
09-01-2009, 11:15 PM
Sure looks like a three-way switch in the photo of the crossover in the "powerpack" which one might assume is the same as the crossover in the 632. :dont-know

Might be a good assumption if the power pack was added to a 632 type cabinet that did not have the horn originally. See the TSB below with the crossover with swtch. However, the MI632 does not have that in the original crossover, but the MI632A model does, so that is the one he must have.

http://www.jblproservice.com/pdf/MI-Series/MI-291.pdf

http://www.jblproservice.com/pdf/MI-Series/MI-632a.pdf

subwoof
09-02-2009, 07:46 AM
all those early models had a 3 position switch in the HF section of the crossover. depending on the position a different value capacitor combination was in use and the maximum "volume" was actually a lower crossover point ( and therefore more energy ) so the diaphragm could bubble/burn at a faster rate.

Stay away from ANY of those tiny or old thread-on drivers. too much to fix and you will be doing it OFTEN.

sub

AFF
09-02-2009, 04:25 PM
all those early models had a 3 position switch in the HF section of the crossover. depending on the position a different value capacitor combination was in use and the maximum "volume" was actually a lower crossover point ( and therefore more energy ) so the diaphragm could bubble/burn at a faster rate.

Stay away from ANY of those tiny or old thread-on drivers. too much to fix and you will be doing it OFTEN.

sub


Should I be worried about the drivers that are in my MI cabs?
I have not yet had the chance to pop the back open to really view the contents so I actually thought they were higher quality. Thanks
-AFF