Bought some P45's - Lots of questions!

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pssturges Posted: Mon, Jul 30 2018 8:46 AM

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Hi all, my first post here. I have just purchased a pair of P45’s. I was able to listen to them before I put down my cash and they sounded great. That combined with the reputation they seemed to have, I thought they would be well worth the modest asking price. Aesthetically, they’re in great condition for their age especially the grills, they are pristine. Having gotten them home and hooked up to my system, I’m feeling a little underwhelmed, however. Although, they are very smooth, they just seem a little lifeless and to be honest, plasticy. I know they are quite old speakers and may need a little TLC to bring them back to life so I cracked them open and had a bit of a look inside. Please bare with me I have a lot of questions and I’m somewhat new to the technical aspects of speaker design and maintenance. I’ve included lots of photos too.

1. Since getting them home I’ve read quite a bit about the bass driver magnets coming loose and freezing the driver. As far as I can tell there is no sign of this at all. The obvious sign of this would be the cones not vibrating and not emitting sound? The magnets don’t seem to have had extra glue added, so it seems surprising to me that they are going so well after all this time. Is it just me or do these drivers look a bit different from others I’ve seen in photos? I’m a little concerned that the drivers may have been replaced with inferior ones.
2. The previous owner said it would probably be worth while replacing the capacitors. Seems reasonable, but have never done this before. I can solder OK but I assume I’ll need to buy some specific specification in the capacitors? What do I need to ask for?
3. The previous owner said he had replaced the sound deadening material inside the box as the previous stuff was crumbling. Does the stuff he used look OK for the purpose? I noticed it was in the compartment that houses the mid on one speaker but not the other. Worth adding it to the second?
4. The previous owner had also added his own terminals to the back panel. They protrude quite a bit which will make speakers impossible to hang flush on the wall. Any suggestions on how I can rectify this. What type of terminals to use, where to place them and what to do with the holes left when I take out these terminals?
5. There seems to have been some sort of seal between the box and the back plate that has degraded and crumbled. How important is this? Worth replacing? What with?
6. Assuming I can get these working well again, the intention is to have a custom made bookshelf installed in my ‘listening room’. I know these are designed to be hung on the wall, but I’m thinking about basically building them into the shelves. How would this best be done? Are they really best hung or are they just as good sitting on a shelf at the appropriate height? I assume they’ll need to sit at the front of the shelf, probably with the grills sitting proud. Should I put a false back behind them so the is no space behind? I’ve included a photo similar to what I have in mind, but with the speakers set higher.

As I said maybe with a bit of work I can get my P45s sounding great. Maybe it’s just my expectations that need adjusting. Anyhow, any help or thoughts would be much appreciated.

Thanks!

Phil

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peternovy replied on Mon, Jul 30 2018 9:42 AM

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As for the more technical issues such as capacitors, dampening foam, terminal removal you'll need to hear from the experts here, but it is strange that they sounded great at the seller's place but not at your place. I imagine there might be a few reasons: maybe they are connected out of phase, or perhaps your amplifier is the culprit? As for the woofers, if they are working when driven and the cone moves smoothly without any rubbing when pressed gently then probably they are OK. 

If you build them tightly into a shelf then - perhaps I am wrong - the whole setup can become boomy, as you will have some resonance from the shelf, especially if you leave space behind them. 

I have a pair of P45's hung on a wall and I can say they are excellent indeed, and look fabulous.

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pssturges replied on Mon, Jul 30 2018 10:25 AM

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Thanks, they do look great as do mine, although I probably would have preferred the wood grain veneer rather than white, but I can live with that.

TBH, I probably rushed my audition with them.They did seem to sound really good at the time. They were just sat on the floor and connected to some sort of older style amp. I didn't pay that much attention but it looked like a fairly standard 70s or 80s amp. My test at home was on my brand new Yamaha RX-v683 set up as 2.0, so probably very different and would no doubt account for at least a different sound. Maybe they just not a great match. I had them sat on top of my very large floor standers right up against the wall to try to simulate as much possible their intended positioning.

The P45's are intended to be connected to another yet to be purchased amp in another room of the house that I'm building. The intention is that will will be another yamaha because of the musiccast feature, although only a stereo one. 

As far as placement, as I said, the cabinet will be custom built in the new house, so It can be however I like, so perhaps they can hang on a false back with a bit of space around them? Plenty of time to work that out though.

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peternovy replied on Mon, Jul 30 2018 10:50 AM

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The synergy between modern and vintage is not always perfect, as far as I know. I myself am using exclusively vintage equipment, so can't comment much on this. Perhaps changing the capacitors might help. Martin (Dillen) should be able to help you with this. One last easy thing to check, if haven't done it already, is that modern often amps have a speaker impedance setting and the P45s are 4Ohm so it is best to check the amp is putting out the correct amount of current.