Rodgers 755 Speaker Relocation & Repair

[Larrytow]

I'm helping a local church with the relocation of, and possibly repairing the drivers in, the 5 speaker cabinets they have. I'm looking for advice on a couple of things. They already took the cabinets down from the shelf they are sitting on, so fixing any drivers that may have foam rot is a thing that needs to be done before re-installation. The reason for the need to relocate them is due to getting stained glass windows in the rear wall of the church. The shelf the speakers were on was blocking the windows that are being replaced with the stained glass. The plan for the new location is to tear out the rest of the stuff on the back wall ( that structure was an air return for an old heating system ), and then make a new shelf higher up on the rear wall above the windows. The speakers will go on the new shelf and be centered, where previously they were not symmetrical with the peak of the ceiling. I think that will be a very good location for them.

I looked at the cabinets today, and all the 6X9 speakers look OK. The low end of the organ sounds ratty, so I figure there must be some drivers in the other cabinets that have bad surrounds. The cabinets are : one model C3 (pedal / low end), two model C1, and two model C2. In reading this forum I have not seen these Rodgers cabinets mentioned much.

They have decorative grills on them, and the backs of the C3 and C1 cabinets look to be nailed / glued on. I figure that the front grill needs to come off to get to the drivers and think I know how they come apart, but am looking for verification. I believe that the bottom trim pieces come off, and then there looks to be a strip of wood to the front edge that needs to come out. Then the whole front grill will slide up and out. Is that about right ? I did not have time today to try this plan out.

Do both the C1 and the C3 have drivers with foam surrounds ? Or just the C3 ?

I already tried to sell them on the idea of just replacing the Rodgers cabinets with good Allen HC ones, and they don't want to go that route for various reasons.

The photos should show better what I have tried to describe.

[Larrytow]

Here are some more photos.

[toodles]

Those were indeed Rodgers speakers from a rather custom line designed for an impressionistic pipe facade-like appearance. I saw some in person once around 1990, but not since then. Unless you know an older Rodgers dealer who remembers these, you may not find any advice about how to access the drivers. Your suspicions about access are probably correct--so I say proceed slowly and carefully.

Incidentally, the JBL driver shown in some of the photos is labelled 2402H is a bullet horn tweeter--no foam in it, so you don't need to take it out to check.

Maybe the church has the original purchase paperwork for the installation--if so, there might be some descriptive material or other clues that might provide some internet search criteria to help.

[myorgan]

You probably already know this, but let me also recommend that if you do end up replacing woofer surrounds, TAKE PHOTOS BEFORE DISCONNECTING. I received one of my organs because they replaced the drivers, and re-connected more than one in reverse polarity inside the cabinet. The complaint was that there was then no bass.

Forewarned-forearmed.

Michael

[Larrytow]

Thank you toodles and myorgan, I've been doing snow work all day, and have an emergency funeral job in the morning. I'll respond more tomorrow afternoon.

[Larrytow]

Hi Guys, sorry for not getting back sooner - been busy with snow removal jobs here. We are having a genuine Winter this season !

Myorgan, thank you for the reminder about polarity. I do actually know that though. And that one can never take for granted that the wire colors are the same in each of the cabinets.

Toodles, it is nice to know that someone has at least seen these types of cabinets before - I never have. I did note the nice tweeter in them, so I can see how they are considered a high end option. So those faces are supposed to look like pipes ? OK, I guess I can sorta see some resemblances, as you said, in an "impressionistic" way. As you can see in the first two photos I posted, they had all of the cabinets installed upside down ! The trim pieces on them are supposed to be on the bottoms I'm sure. Then the front face would look more like pipes with the foot of the pipe on the bottom too.

I got it on my schedule to go back there on the 14th of this month to take them apart and see what is in them. If there is foam rot, the drivers will get either refoamed or replaced. The pedal low end makes something in them sound really ratty, so I figure it is indeed rotted foam surrounds.

They are going to take out all of the structure above the windows, and put a nice shelf on the back wall. I advised them to make it larger in depth than the previous one, so that future work on the speakers, or replacements or additional ones can be accommodated easily. One question is how high up into the peak should the shelf be placed. The issue I am thinking about is should the speakers be at a level above or below the ceiling fan level ? Not sure it matters that much considering the distance between the speakers and the rearmost fan, but you don't really want an Austin style fan tremolo going all the time, right ?

When I take the cabinets apart, I will take good photos and post them. Thanks for the advice so far !

[myorgan]

One question is how high up into the peak should the shelf be placed. The issue I am thinking about is should the speakers be at a level above or below the ceiling fan level ? Not sure it matters that much considering the distance between the speakers and the rearmost fan, but you don't really want an Austin style fan tremolo going all the time, right ?

I'm glad you brought that up. Once, my wife played in a location with a ceiling fan, and it made her violin sound like it was playing under water.

With so many churches that have ceiling fans, I've wondered how much ceiling fans affect the sound of organ speakers as the sound passes under them. Does anyone have acoustical information they can share?

In answer to Larry's question, my inclination would be to place the speakers as high as possible so they're all at the same level, or grouped in two levels if they're stacked on those shelves. It depends on the speakers you are finally going to use, and their dimensions. That's my opinion based on my experiences.

Michael

P.S. If my question sidetracks this thread, I can start another thread and move all related posts to that thread.

[Larrytow]

The way it is planned, right now anyhow, is to build the shelf similar to the previous one, but a bit deeper and higher up. And more sturdy. Then put the existing speaker cabinets back in the same configuration - tall bass one in the center. I will advise them to put them right side up too.

I realize that the bass channel so high up in the church is not the best for getting deep bass, and have mentioned that a subwoofer in a balcony corner would be a good addition. But there is no money or desire to do that right now. The whole speaker relocation project is just a job that needs to be done this spring to accommodate the new stained glass windows. Stained glass is expensive of course, so major upgrades to the organ audio system is not in the cards right now.

The ceiling fan issue is one I have never had a thought about before this. It is an interesting question for sure. In this installation it does look like the shelf could be higher or lower than the fans ( suppose I should actually measure the heights instead of guessing ! ), and I think that above may well be best. But that depends some on which way the fans are blowing too. The church is air conditioned, so they may change the direction they turn from summer to winter. Gotta check that too.

This church does not use the organ often, but they do want to keep it in good functional order. It is used for big festival services, when they can get an organist to play it, but for weekly services they use CD accompaniments for the hymns and liturgy. As to Why there is no resident organist there anymore is a long, convoluted, sorta political, story that we need not get into.

[jbird604]

Glad toodles recognized the cabinets. I have never seen any like that, and was about to opine that they must have been some kind of home-brew units.

Maybe you can shine a strong flashlight through the grille cloth before you go to the trouble to remove the fronts. If the 6x9 and bullet drivers are like others Rodgers has used, they will need no repair. But I'll bet there are rotten foam surrounds on all bass drivers. It's a good thing they're having this done, even if the organ gets limited use. It will make all the difference in the world in the sound!

As to ceiling fans, I first noticed how annoying they are many years ago when tuning a piano in a church with ceiling fans going. Seems to spoil the sound even when the fans are some distance from the organ (or piano), as it disrupts the reflected sound. Probably worse if the fan happens to be right in front of a speaker cabinet though. I'd advise them to keep the speakers as far from fans as possible, and certainly not in line with a fan's blades.

[Larrytow]

The 6X9 speakers are all in nice shape. They are in open back cabinets, so that was easy to determine. I'm betting on rotted foam in the other three also. Sounded that way to me the last time I played it.

[John Vanderlee]

They would definitely interfere! Some pipe organ builders use a paddle like fan above the pipes as a tremolo.
My wife teaches flute at home. She never turns the overhead fan on during a lesson for that very reason.

[toodles]

I vaguely remember these were called "Casework Speakers" offered about the time that Rodgers was heavily into their "combination" organs. I saw them when I was trying out a Rodgers 645/655 in the dealer's garage. There were a few of those speakers, and he explained about them--they looked rather ugly to me. He also had a Schober Recital organ in his garage--taken in on trade. The Schober looked a little more impressive than their catalog photos made them appear. I had a similar reaction to a Schober Theatre organ I saw at a Salvation Army Thrift store, but it had some of the wood parts knocked off on one edge--I was sorry to see that condition.

[Larrytow]

Here is the update to this project. I was over there several days ago and inspected the drivers. I've just been kinda busy lately, and have not got around to posting the results.

The medium size cabinets are Rodgers C2 ones, and they have cloth / rubber surrounds on the 12" drivers. They are in fine shape.

The large bass cabinet is a Rodgers C3 ( which is way taller than it needs to be, with an empty section over the actual enclosure ), and it has two 12" foam surround drivers in it, along with a port. Those are also in great shape. I'm sure they have been re-foamed at some point, because the interior of the cabinet had lots of foam shards still in it.

The front of the cabinets came out just as I suspected they would. There is a fill strip screwed onto the top of the cabinet about 3" wide. Take that out and the front grille panel slides up and out to access the drivers. The rest of the cabinet is glued together.

All the drivers are Foster brand, made in Japan. I've never heard of them before this, but a bit of searching reveals that they are the parent company of Fostex. They seem to be well made drivers.

So the terrible rattling sound on the low notes is not because of busticated speakers ! There were people there that day setting up scaffolding for doing the shelf rebuilding job. Once they had it set up, they were looking into the old ventilation structure way up in the peak ( that will be removed as well, as they have A/C now ) and discovered a large vent fan hidden away up in there. That vent fan is not well attached - just sorta sits on a shelf up there, and I figured that is the rattle source. I stuck around while they were preparing to get it down and out of there, and once they were up close to it they found one of the side panels on it was loose as well. So THAT is the source of the rattle noise !

Everyone ( besides myself ) is pleased that the issue has been solved.

[Larrytow]

And one more photo :

[jbird604]

Great news!

[Larrytow]

OK, here is another update on this project. They now have the new shelf installed, and the speakers were put back in place. They contacted me saying that it really sounds awful now. The Trustees and Elders of the church are actually doing this whole project, so I'm figuring they screwed up the wiring in some way. I will be going to inspect the situation in the next few days.

With that in mind, I am looking at the photos I have of the organ innards, and see a device in the console that I do not recognize, or know why it is there, or what it's function is / was. It has speaker wires going to / coming from it, so there may be an issue with it. However, it does not look like All the speaker wires come from it. But, the wiring is sorta tangled in there, so it is hard to follow with just the photo.

The device I am wondering about is marked WM-2001 on the front panel. It has an On/ Off switch on it also. It is the black metal rectangular box on the right hand side of the console front panel ( as seen from the rear ). I googled what seems to be the obvious model # on it, but came up with nothing informative.

My thought is that it might be some sort of reverb. And it is either not working, or disconnected somehow. But, I am just guessing here. Obviously I will learn more when I go to check things out, but could benefit from the collective wisdom here. So, what might it be ?

The organ has just 3 channels, as far as I can tell. But 5 speaker cabinets. The pedal channel should go to the large C3 cabinet, of course. Then there are 2 C2 cabinets, and 2 C1 cabinets ( the ones with the 6X9s ). Is this device a crossover perhaps ? The actual Rodgers output panel has only the 3 speaker cables attached to it. So the 2 main channels get split between the other 4 speakers somewhere it seems .

[jbird604]

That mysterious unit is an amplifier, possibly made by Carver, and I see those now and then hung onto Rodgers organs as additional amps for various reasons. Perhaps the installing dealer put it there to drive the additional two speaker cabinets ?? ... Probably not necessary of course, as the Rodgers amps could surely drive more than one speaker cabinet per channel. Nice amp though.

The six holes in the control panel are for the bass, treble, and level controls of the two channels. Ordinary pots, so they need "exercise" like all pots do. But that may not fully explain why it sounds so bad. You'll just have to give it a listen. I'd disconnect all the speaker wires, then hook up just one at a time to see if a particular channel is distorted. No telling what the real problem is. Could be anything if the church fathers are doing their own organ work!

Anyway, if the speakers are in good shape and properly connected to the amps, you should be able to solve the problem in short order.

[Larrytow]

Thank you John ! I will have a few more questions I think, but will post them later or tomorrow. Don't know why it did not occur to me that it might be an amp, because that makes perfect sense now.

[jbird604]

I wouldn't have recognized it as amp either had I not seen several just like it. We took in a Rodgers Cheetah organ (early 90's) a few weeks ago, and the installing dealer had used an amp just like that to power some external Walker speaker cabinets he had sold with it. This amp is ideal for use with Rodgers organs because it has a remote power-on feature much like the turn-on feature of all Rodgers amps, and it has built-in turn-on/turn-off muting. I used that very traded-in amp in a pinch recently to replace a two-channel Allen ADC amp and it works beautifully. Didn't need the Allen muting voltage connected.

[Larrytow]

Well, I still have not gotten back to this church yet, but hope to this coming week. Upon further review of my photos from this church, I see that there are indeed two antiphonal speakers in the front of the room. I'll bet that is what the Carver amp is in there for ? When I get back there to check things out better, I will trace everything to see what is what.

I have an opportunity to get a really nice set of eight Rodgers FR 1.7 cabinets, and two SW 7.5 cabinets. The foam is excellent in all of them, and they have the white grilles on them. All are finished cabinets as well.

I'm thinking even though the organ is analog, and these cabinets were on a PDI instrument, they might make this 755 sound very nice. That is figuring that there is nothing wrong inside the organ, causing the reported lousy sound right now. What do you think of that plan ?

[toodles]

FR1.7 cabinets and the SW7.5 should work quite nicely on the 755.