pauljh
Active Member
I've been a fan of Infinity speakers since the time they only had one product: the Servo Static 1, which I heard at Woodland Stereo in 1968. My first pair of Infinity speakers was their second product, the original Infinity 2000, and I still have those speakers. I also have a pair of InfiniTesimals (0.3) which I use as front speakers in my home theater system.
Recently, having regressed back to the interests of my youth, I've been trolling eBay and Craigslist ads for Infinity speakers. Just before Christmas 2017 I saw a pair of RS1s (not a or b) for sale locally on eBay for a what seemed a reasonable price. I ended up winning the auction, and the seller (a local sound reinforcement company) even delivered them, hauling them up four flights of stairs to my loft.
They were mostly intact, but it was obvious they had led a hard life. The cabinets show water damage at the bottom, and not all of the drivers were pristine (or even working). I replaced two dead rear-firing tweeters with replacements from eBay, and replaced an oversized fuse or two (why is there a 3A fuse in this tweeter circuit?!?), and then started listening and adjusting.
The system had a hum and ground loop buzz when using the Infinity servo-crossover. I tried various configurations and ground lifting schemes but never got things quiet. Since I had a Rane AC22B crossover lying around, I gave up for now and swapped the Infinity crossover out for the Rane, and set the (24db/octave) crossover point to 120Hz. (The Infinity crossover implements a passive second-order crossover point at 150Hz). Finally the system was dead silent when it should be.
(I’ve worked on the Infinity crossover a bit since I put it on the shelf, and found that the ground shields on the RCA connectors weren’t all at ground potential, so I’ve ordered some gold-plated replacements from China and will install them when they arrive. I’m hoping that will quiet down the noise so I can use the Infinity crossover).
After setting up the Rane crossover, I balanced the woofers with the midrange/tweeters by ear, but was disappointed in the low bass. Out came the laptop with Room EQ Wizard on it, and I got out my instrumentation microphone and looked at the room response. Without the Infinity servo crossover, the bass towers rolled off at 12db/octave starting at 60Hz or so. Since I was messing with REW anyway, I created some filters to smooth out the room response and a shelf filter to bring back the bass down to 30Hz. Since I no longer listen to vinyl (it's been about 20 years - is anyone interested in a SOTA Sapphire turntable, Dynavector Karat 23R cartridge and a Linn Ittok II tonearm?), and no longer listen directly to CDs, my only music source is digital from a PC running JRiver Media Center. JRiver has a very handy DSP module that will use convolution filter sets that you can generate with REW, so I installed my filters and things sounded much, much better. These speakers now go really low: for instance "Thanks to You" by Boz Scaggs is very impressive, as is the Chesky binaural demo recording of the Bach Toccata & Fugue.
As I mentioned, there are some cosmetic issues with the enclosures, so I'll eventually be taking everything apart to refinish the cabinets. Also, though they work, the upper midrange EMIMs look pretty sad with some delamination of the traces from the diaphragms (presumably from playing Rock at sound reinforcement levels). Perhaps I'll invest in some replacement EMIMs and keep what I have as spares.
Since, as far as I can tell, the only difference between the RS1, RS1a, and RS1b is the crossover, and since the crossover schematic to the RS1b is available, I’ve decided to upgrade my crossovers to RS1b specs. My next long post in this audio adventure thread will be about that work, and what I learn.
Recently, having regressed back to the interests of my youth, I've been trolling eBay and Craigslist ads for Infinity speakers. Just before Christmas 2017 I saw a pair of RS1s (not a or b) for sale locally on eBay for a what seemed a reasonable price. I ended up winning the auction, and the seller (a local sound reinforcement company) even delivered them, hauling them up four flights of stairs to my loft.
They were mostly intact, but it was obvious they had led a hard life. The cabinets show water damage at the bottom, and not all of the drivers were pristine (or even working). I replaced two dead rear-firing tweeters with replacements from eBay, and replaced an oversized fuse or two (why is there a 3A fuse in this tweeter circuit?!?), and then started listening and adjusting.
The system had a hum and ground loop buzz when using the Infinity servo-crossover. I tried various configurations and ground lifting schemes but never got things quiet. Since I had a Rane AC22B crossover lying around, I gave up for now and swapped the Infinity crossover out for the Rane, and set the (24db/octave) crossover point to 120Hz. (The Infinity crossover implements a passive second-order crossover point at 150Hz). Finally the system was dead silent when it should be.
(I’ve worked on the Infinity crossover a bit since I put it on the shelf, and found that the ground shields on the RCA connectors weren’t all at ground potential, so I’ve ordered some gold-plated replacements from China and will install them when they arrive. I’m hoping that will quiet down the noise so I can use the Infinity crossover).
After setting up the Rane crossover, I balanced the woofers with the midrange/tweeters by ear, but was disappointed in the low bass. Out came the laptop with Room EQ Wizard on it, and I got out my instrumentation microphone and looked at the room response. Without the Infinity servo crossover, the bass towers rolled off at 12db/octave starting at 60Hz or so. Since I was messing with REW anyway, I created some filters to smooth out the room response and a shelf filter to bring back the bass down to 30Hz. Since I no longer listen to vinyl (it's been about 20 years - is anyone interested in a SOTA Sapphire turntable, Dynavector Karat 23R cartridge and a Linn Ittok II tonearm?), and no longer listen directly to CDs, my only music source is digital from a PC running JRiver Media Center. JRiver has a very handy DSP module that will use convolution filter sets that you can generate with REW, so I installed my filters and things sounded much, much better. These speakers now go really low: for instance "Thanks to You" by Boz Scaggs is very impressive, as is the Chesky binaural demo recording of the Bach Toccata & Fugue.
As I mentioned, there are some cosmetic issues with the enclosures, so I'll eventually be taking everything apart to refinish the cabinets. Also, though they work, the upper midrange EMIMs look pretty sad with some delamination of the traces from the diaphragms (presumably from playing Rock at sound reinforcement levels). Perhaps I'll invest in some replacement EMIMs and keep what I have as spares.
Since, as far as I can tell, the only difference between the RS1, RS1a, and RS1b is the crossover, and since the crossover schematic to the RS1b is available, I’ve decided to upgrade my crossovers to RS1b specs. My next long post in this audio adventure thread will be about that work, and what I learn.
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