Infinity RS3A Project

[Seppo]

Seppo = a great guy! Glad they went to you as I know you've gotta be loving them! And yes.... this is a very small world indeed.

...

Good to hear from you!

Your RS-IIIa's really got me back into audio, hook, line and sinker. These speakers are just great all around Infinity's w/ EMIT highs, good bass, and just very balanced sounding. But of course, my Onkyo receiver was not up to the job though so I already last spring updated to Onkyo A-9070 integrated (150 wpc at 4 Ohm), which works great w/ RS-IIIa's, never running out of power.

But having seen the light with RS-IIIa's, it so happened that just a few weeks ago I picked up RS-II's from Toronto, which I have to say, are just fantastic speakers. The dipole midranges and tweeters work sweet magic. So now I need a way sturdier dedicated amp (since my new Onkyo went to limp mode already once), looking into Adcom's or Haflers at the moment..oh boy

The RS-IIIa's are now waiting in storage for the kids to grow up a bit, so I can safely put them as the main fronts for the HT...

Best,
Seppo

 

[Bkphoto]

is there foam in the dome tweeter like the foam from the cones that rotted? I can't quite tell.

how do you get the crossovers and terminal out of these anyway? I was told there may have been fuses somewhere and I need to check the caps as well.

take your time...

there are screws and glue holding in the crossover..take the screws out and run a putty knife along the edge...

the tweeters and mids have protection circuits that reset on their own...I don't because I took mine out...no need really unless you are running these with a small amp and you like listening to metallica at 3:00 on the dial...

 

[lightfall]

Thanks, I wasn't sure if I was supposed to tear out all the baffling and go through the speaker hole to get at it!

 

[Bkphoto]

yes....its the only way

 

[lightfall]

Scraping off that tweeter surround foam was a serious nightmare. No chemicals would touch that tenacious fossilized adhesive. For anyone curious I am confident there is no way to strip that glue and leave the underlying finish intact.

 

[Bkphoto]

told you....wide chisel and an orbital sander...

 

[lightfall]

I will post up some photos of my restore progress.

Question though: I used the simply speaker refoam kit (excellent service from them actually) and was able to refoam the four woofers. I used the 30hz method and everything is sitting nice and even.

In any case I am using a Phase Linear 400 Series 2 amp.

After testing things out with various sources I feel like the bass response on the speakers is very weak. The entire midrange and bass end is thin. I tried repositioning, changing interconnects, different speakers, etc. I am fairly confident the speakers themselves sound weak and I do not recall them being described as such anywhere. Should they be very weak after the refoam? Will that change dramatically as they warm up or did I do something wrong?

Thoughts much appreciated, I know this is subjective but the cabinets sound really crisp and beautiful but very whispy bottom end. Even with a sub I think some deep mids would be missing a presence.

Also when testing 30hz I got the volume up to where the woofers have maybe an inch of excursion and they appear to not be rubbing anything so I hope they are OK. I get a little flapping sound from each cabinet but I think it may be some of the baffling fabric while testing with that powerful 30hz tone as I don't hear it originating from the cones.

 

[Bkphoto]

the foams need a little time to break in...

where are your pots set at...?

 

[lightfall]

I tried the pots far left, middle, far right, no real appreciable difference to be honest.

 

[lightfall]

I forgot to mention I did add inline fuses on the + speaker wire. I started with 1.5amp fast blo as suggested by the original Phase Linear manual because some of the infinity speakers can dip to 4ohms and really push the PL which could potentially (old gear) cause failure and DC.

However those fused cables sound pretty much fine with another two sets of speakers.

 

[goodolpg]

Are the woofers wired correctly?
Many times a lack of bass has been found to be a wiring problem especially with speakers having dual woofers.

 

[lightfall]

I did read about that, so I double checked. I put the red + wire to the red terminal on each woofer. Unless they are supposed to be reversed? Also they both have fair movement at 30hz, would that even happen if they were reverse wired? Should I try swapping one of the positives to a negative and see if that helps?

 

[Bkphoto]

+ wire to bottom woofer...then there is a purple wire which goes from the bottom woofer neg to top woofer + then neg from top woofer back to crossover...

 

[Bkphoto]

I forgot to mention I did add inline fuses on the + speaker wire. I started with 1.5amp fast blo as suggested by the original Phase Linear manual because some of the infinity speakers can dip to 4ohms and really push the PL which could potentially (old gear) cause failure and DC.

However those fused cables sound pretty much fine with another two sets of speakers.

well they can dip below 4 ohms and i've always regarded them as 4 ohm speakers anyway...

not really sure why you would put fuses in there, anyway, my suggestion is to have the PL looked at to make sure things are fine...if your amp can't take a 4 ohm load you have the wrong amp...

 

[lightfall]

Fuses would protect the speakers if the amp threw DC right? With the help of a friend I have been restoring the PL400. It is very nice but I haven't fully put it through the paces yet. I have thoroughly tested it but I am being cautious.

 

[lightfall]

+ wire to bottom woofer...then there is a purple wire which goes from the bottom woofer neg to top woofer + then neg from top woofer back to crossover...

I did not realize that the top woofer had a red wire to the neg and the purple to the pos I will try the reversal.

 

[Bkphoto]

If your getting DC on the amp outputs you have a bias issue or something else is lurking around...

 

[lightfall]

If your getting DC on the amp outputs you have a bias issue or something else is lurking around...

I'm sorry I didn't word that very clearly. No DC offset, bias is within spec, but I have heard that if a PL amp goes there is little warning and they will throw DC because there was no speaker protection circuit built in

 

[lightfall]

The amp is rated for 4ohm as well.

 

[Seppo]

I popped the woofers in my RS-IIIa's and RS-IIs out just the other day to check the wiring, and see if I could swap the woofers on the fly (nope, soldering needed on the RS-II side). I also took a few photos, thinking that someone might find them useful at some point...and here we are...

Top woofer:

Bottom woofer:

And both in the same picture:

In short, you have to have the dual woofers in series, and in-phase (same polarity). If you put the woofers in opposite phase (opposite polarity strictly speaking), you will get very limited bass. Trust me, been there, done that



And, while we are at it, just for the sake of comparison, here's one of the woofers in RS-II:

As far as I can tell, the woofers are identical, but the wiring is much much heavier gauge in RS-IIs.