Polk Reserve R700 – Eight Pairs of Failed Tweeters (Vol. 1)
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Ylbs
Posts: 2
Hello everyone!
I would like to share my experience with the Polk Reserve R700 and discuss it with other owners, audiophiles and people familiar with loudspeaker design.
**I have gone through eight pairs of failed Pinnacle Ring Radiator tweeters.**
After years of using these speakers, testing different amplifiers, investigating polarity and making adjustments to the crossover and EQ, I have reached a conclusion:
**In my experience, the Pinnacle Ring Radiator tweeter cannot withstand the signal it receives during louder listening. The bass and midrange drivers still have considerable performance available, but the tweeter reaches its limits and fails.**
I believe the high-frequency section needs better attenuation or protection.
This is my conclusion based on what I have personally experienced, and I would like to discuss it with people who may agree, disagree or have technical evidence that explains the problem.
## Why I bought the R700
I originally wanted speakers capable of playing considerably louder than my previous Polk speakers.
At that time, I was using a Denon AVR-X3800H. My dealer told me that my amplifier was not the problem and that my existing speakers were the limiting factor.
Based on that advice, I purchased the R700.
What I particularly appreciate about the R700 is its bass capability. I have never considered the overall sound perfect, especially the high frequencies, which I have often found too aggressive.
## The Audyssey polarity issue and what happened at the distributor
When I first calibrated the R700 speakers with Audyssey, the Denon repeatedly reported reversed speaker polarity, even though the external connections were correct.
The speakers were taken to the local Polk distributor for testing.
They remained there for approximately one week.
When I collected them, I was told that the technicians had reversed the internal polarity of the bass section to match the midrange and high-frequency section.
They assured me that the speakers had been tested and were working correctly.
However, when I connected them at home, the sound was immediately unacceptable to me. The bass and the rest of the frequency range no longer integrated properly.
I do not wish to disrespect the technicians, but I believe this intervention ruined the original sound of my speakers.
I even removed the front drivers from one speaker, inspected and measured the connections myself, and carefully reassembled it.
Because the distributor had modified the internal wiring, I insisted on replacement speakers.
Initially, they offered me different speakers rated at approximately 150 W. I declined because I had purchased the R700 specifically for their greater output capability.
The distributor then tested several pairs of brand-new R700 speakers.
**Every pair produced the same reversed-polarity warning during Audyssey calibration.**
According to the distributor, Polk Audio confirmed that the R700 was intentionally designed with this polarity arrangement and that the manufacturer was already aware of the Audyssey warning.
Therefore, this was apparently not a defective production batch.
My question remains: why was the internal wiring of my original speakers changed to correct something that Polk reportedly considered normal?
## Amplifier upgrades and eight pairs of failed tweeters
I started with the Denon AVR-X3800H, which clearly lacked the power needed to bring out the full potential of the R700 speakers.
I replaced it with the more powerful Denon AVR-X6800H.
Later, I connected a Marantz MM7025 stereo power amplifier to the Denon's front pre-out outputs.
However, even the Marantz did not deliver the bass and midrange performance I expected from the R700.
I eventually replaced the Marantz with a NAD C298.
**The NAD C298 was the first amplifier that truly brought the R700 bass and midrange drivers to life.**
Unfortunately, both tweeters failed on the very first day while I was adjusting the sound with the NAD C298.
Tweeter failures occurred with different amplifiers, and over the years I have gone through eight pairs.
What makes this particularly frustrating is that, in my experience, the bass and midrange drivers had not yet reached their limits.
The tweeter failed first.
This is one of the main reasons I believe the high-frequency driver is the weak link in the R700.
I would like to share my experience with the Polk Reserve R700 and discuss it with other owners, audiophiles and people familiar with loudspeaker design.
**I have gone through eight pairs of failed Pinnacle Ring Radiator tweeters.**
After years of using these speakers, testing different amplifiers, investigating polarity and making adjustments to the crossover and EQ, I have reached a conclusion:
**In my experience, the Pinnacle Ring Radiator tweeter cannot withstand the signal it receives during louder listening. The bass and midrange drivers still have considerable performance available, but the tweeter reaches its limits and fails.**
I believe the high-frequency section needs better attenuation or protection.
This is my conclusion based on what I have personally experienced, and I would like to discuss it with people who may agree, disagree or have technical evidence that explains the problem.
## Why I bought the R700
I originally wanted speakers capable of playing considerably louder than my previous Polk speakers.
At that time, I was using a Denon AVR-X3800H. My dealer told me that my amplifier was not the problem and that my existing speakers were the limiting factor.
Based on that advice, I purchased the R700.
What I particularly appreciate about the R700 is its bass capability. I have never considered the overall sound perfect, especially the high frequencies, which I have often found too aggressive.
## The Audyssey polarity issue and what happened at the distributor
When I first calibrated the R700 speakers with Audyssey, the Denon repeatedly reported reversed speaker polarity, even though the external connections were correct.
The speakers were taken to the local Polk distributor for testing.
They remained there for approximately one week.
When I collected them, I was told that the technicians had reversed the internal polarity of the bass section to match the midrange and high-frequency section.
They assured me that the speakers had been tested and were working correctly.
However, when I connected them at home, the sound was immediately unacceptable to me. The bass and the rest of the frequency range no longer integrated properly.
I do not wish to disrespect the technicians, but I believe this intervention ruined the original sound of my speakers.
I even removed the front drivers from one speaker, inspected and measured the connections myself, and carefully reassembled it.
Because the distributor had modified the internal wiring, I insisted on replacement speakers.
Initially, they offered me different speakers rated at approximately 150 W. I declined because I had purchased the R700 specifically for their greater output capability.
The distributor then tested several pairs of brand-new R700 speakers.
**Every pair produced the same reversed-polarity warning during Audyssey calibration.**
According to the distributor, Polk Audio confirmed that the R700 was intentionally designed with this polarity arrangement and that the manufacturer was already aware of the Audyssey warning.
Therefore, this was apparently not a defective production batch.
My question remains: why was the internal wiring of my original speakers changed to correct something that Polk reportedly considered normal?
## Amplifier upgrades and eight pairs of failed tweeters
I started with the Denon AVR-X3800H, which clearly lacked the power needed to bring out the full potential of the R700 speakers.
I replaced it with the more powerful Denon AVR-X6800H.
Later, I connected a Marantz MM7025 stereo power amplifier to the Denon's front pre-out outputs.
However, even the Marantz did not deliver the bass and midrange performance I expected from the R700.
I eventually replaced the Marantz with a NAD C298.
**The NAD C298 was the first amplifier that truly brought the R700 bass and midrange drivers to life.**
Unfortunately, both tweeters failed on the very first day while I was adjusting the sound with the NAD C298.
Tweeter failures occurred with different amplifiers, and over the years I have gone through eight pairs.
What makes this particularly frustrating is that, in my experience, the bass and midrange drivers had not yet reached their limits.
The tweeter failed first.
This is one of the main reasons I believe the high-frequency driver is the weak link in the R700.
Comments
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You must not be able to sense when distortion and clipping are occurring. That is the only thing that kills tweeters unless your amps are sending DC current. Most of us who have the Reserve or Legend series have not seen any tweeter failures. I think you are expecting too much of a smallish floor stander. If you are expecting modern Dolby Cinema level experiences (in excess of 115dB in peaks), you need a more efficient speaker setup.
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"I believe the high-frequency section needs better attenuation or protection."
There are three ways to protect a tweeter. One is to install a fast acting in-line fuse in series with the positive wire going to the tweeter's terminal. This would be fairly simple to implement requiring a fuse holder and some wire. The second is with a thermistor (which would function as a fast acting resettable fuse) being placed similarly to where the fuse would be placed. If the thermistor were paralleled with a resistor the tweeter's output would be reduced whenever the device were triggered. The third approach is to install a small bulb in series with the tweeter. This would drain off some the excess current and if installed on the front of the cabinet act as a type of overload beacon, telling you to reduce the volume a bit and still save the tweeter. Polk has used all three devices in the past. -
You must not be able to sense when distortion and clipping are occurring. That is the only thing that kills tweeters unless your amps are sending DC current. Most of us who have the Reserve or Legend series have not seen any tweeter failures. I think you are expecting too much of a smallish floor stander. If you are expecting modern Dolby Cinema level experiences (in excess of 115dB in peaks), you need a more efficient speaker setup.
Even a perfect test sine wave can't exceed a tweeter's maximum power handling rating and perhaps overheat the voice coil if there is no protection?
Audioholics review said it was about 6 ohms nominal impedance. Polk amplifier recommendations are up to 300W and that NAD amp is probably rated around 260W at 6 ohms. Of course they only give 8 and 4 ohms ratings but that's interpolated. No shortage of power but the NAD can put out a bit more than that in short dynamic peaks. Dynamic power rating maybe 375ish W at 6 ohms. Not a tremendous amount of headroom but pretty respectable.
@Ylbs I'm curious if you have an sPL meter and have used it when you have one of these failures? Someone who listens loud must have one.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Gardenstater wrote: »You must not be able to sense when distortion and clipping are occurring. That is the only thing that kills tweeters unless your amps are sending DC current. Most of us who have the Reserve or Legend series have not seen any tweeter failures. I think you are expecting too much of a smallish floor stander. If you are expecting modern Dolby Cinema level experiences (in excess of 115dB in peaks), you need a more efficient speaker setup.
Even a perfect test sine wave can't exceed a tweeter's maximum power handling rating and perhaps overheat the voice coil if there is no protection?
@Ylbs I'm curious if you have an sPL meter and have used it when you have one of these failures? Someone who listens loud must have one.
I dunno. I've listened to a lot of loud music through the last 40 years on countless different system configurations, and I have never blown a tweeter. Someone who blows through eight pairs of tweeters, which are the same as what is in my R200, is doing something wrong. I had my R200 hooked with a 250wpc Class-D amp for several months and did plenty of spirited listening. The teeeters are fine.
