Polk Reserve R700 – Eight Pairs of Failed Tweeters (Vol. 2)
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My experiments with speaker polarity
After repeated failures, I experimented with reversing the speaker cable polarity at the amplifier terminals.
I discovered that reversing the external polarity did not noticeably affect the bass performance.
However, the tweeters appeared to last longer.
## Crossover and my conclusion about tweeter protection
After repeated failures, I examined the R700 crossover board.
The midrange and tweeter sections have separate outputs on the crossover.
My conclusion is that the Pinnacle Ring Radiator tweeter receives more signal during loud playback than it can reliably withstand.
**I believe the tweeter needs greater attenuation or a more effective protection arrangement to match the output capability of the rest of the speaker.**
I am particularly interested in whether other owners have investigated the crossover's tweeter circuit, resistor values, filter slopes and protection.
## My current EQ settings
Today, my NAD C298 drives the R700 front speakers, while the Denon AVR-X6800H manages the surround system. My Marantz MM7025 is still in use, powering the rear speakers.
The other 11 speakers in my system have broadly smile-shaped EQ curves, with boosted bass and treble.
The R700 front speakers are different.
I have deliberately reduced their upper frequencies below the EQ zero line.
**With this configuration, the tweeters have survived so far.**
I also have Polk ES20 speakers positioned above the R700s and angled slightly downward, contributing to the overall front sound.
The current high-frequency performance is reasonably satisfactory to me.
However, I find it unacceptable that I have had to reduce the high-frequency output so significantly because I no longer trust the tweeters to survive louder listening.
I can provide photographs of the EQ settings and crossover if anyone is interested in examining them.
## Concerns about Polk center speakers
My current center speaker is a Polk ES30.
I have considered upgrading to a substantially more capable center speaker, such as the Polk Legend L400.
However, the L400 also uses Pinnacle Ring Radiator tweeter technology.
After experiencing eight pairs of failures with the R700, I am reluctant to purchase another expensive speaker using the same tweeter technology.
I have also encountered reports of tweeter failures involving Polk center speakers.
My concern is not whether a center speaker has the same power rating as a floorstanding speaker. It is whether its tweeter has sufficient durability and protection for its intended use.
This is one reason I have been considering replacing the entire front speaker system with JBL Studio 698 floorstanding speakers and a matching JBL Studio 665C center.
## Earlier Polk forum discussions
I have discovered that similar concerns were being discussed years ago.
**May 2022 – Dead tweeters on one month old R700's**
https://forum.polkaudio.com/discussion/comment/2684240
In this discussion, another R700 owner describes losing both tweeters during louder listening while the bass and midrange drivers continued working.
Polk supplied replacement tweeters.
The owner later reported that a Polk technician had mentioned a batch of defective tweeters.
Another participant also suggested checking the crossover for damaged resistors.
Related comment:
https://forum.polkaudio.com/discussion/comment/2684246
**June 2023 – Polk R700 Polarity & other issues**
https://forum.polkaudio.com/discussion/comment/2731332
This discussion was particularly interesting to me.
The author, HalfOhm, describes R700 speakers with disappointing bass balance and excessively prominent midrange and treble.
He also reports that changing polarity made the upper frequencies sound smoother.
Most importantly, he contacted Polk Audio about the internal polarity arrangement and reported that Polk confirmed the woofers were intentionally connected with opposite electrical polarity relative to the midrange and tweeter section because of the crossover design.
This is remarkably similar to the explanation my distributor eventually received from Polk.
These discussions make me question whether the issues I have experienced are really isolated incidents.
## What I would like to discuss
I would particularly like to hear from other R700 owners and technically experienced members about the following:
1. Have you experienced Pinnacle Ring Radiator tweeter failures during louder listening?
2. Do you believe the R700 tweeter receives excessive power relative to its capabilities?
3. Has anyone measured the crossover's tweeter circuit or investigated whether greater attenuation or protection would improve reliability?
4. Has Polk made any changes to the tweeter or crossover since the problems discussed in 2022?
5. Have Legend L400 owners experienced similar issues with the Pinnacle Ring Radiator tweeter?
6. Has anyone received a detailed technical explanation from Polk Audio about repeated tweeter failures?
I am not asking everyone to agree with me.
I have spent considerable time investigating these problems and have reached my own conclusion based on eight pairs of failed tweeters, different amplifiers, polarity experiments and crossover adjustments.
**My conclusion is that the Pinnacle Ring Radiator tweeter is not sufficiently robust for the output capability of the R700 during louder listening.**
I would welcome a serious technical discussion, including evidence that challenges my conclusion.
Thank you for reading.
After repeated failures, I experimented with reversing the speaker cable polarity at the amplifier terminals.
I discovered that reversing the external polarity did not noticeably affect the bass performance.
However, the tweeters appeared to last longer.
## Crossover and my conclusion about tweeter protection
After repeated failures, I examined the R700 crossover board.
The midrange and tweeter sections have separate outputs on the crossover.
My conclusion is that the Pinnacle Ring Radiator tweeter receives more signal during loud playback than it can reliably withstand.
**I believe the tweeter needs greater attenuation or a more effective protection arrangement to match the output capability of the rest of the speaker.**
I am particularly interested in whether other owners have investigated the crossover's tweeter circuit, resistor values, filter slopes and protection.
## My current EQ settings
Today, my NAD C298 drives the R700 front speakers, while the Denon AVR-X6800H manages the surround system. My Marantz MM7025 is still in use, powering the rear speakers.
The other 11 speakers in my system have broadly smile-shaped EQ curves, with boosted bass and treble.
The R700 front speakers are different.
I have deliberately reduced their upper frequencies below the EQ zero line.
**With this configuration, the tweeters have survived so far.**
I also have Polk ES20 speakers positioned above the R700s and angled slightly downward, contributing to the overall front sound.
The current high-frequency performance is reasonably satisfactory to me.
However, I find it unacceptable that I have had to reduce the high-frequency output so significantly because I no longer trust the tweeters to survive louder listening.
I can provide photographs of the EQ settings and crossover if anyone is interested in examining them.
## Concerns about Polk center speakers
My current center speaker is a Polk ES30.
I have considered upgrading to a substantially more capable center speaker, such as the Polk Legend L400.
However, the L400 also uses Pinnacle Ring Radiator tweeter technology.
After experiencing eight pairs of failures with the R700, I am reluctant to purchase another expensive speaker using the same tweeter technology.
I have also encountered reports of tweeter failures involving Polk center speakers.
My concern is not whether a center speaker has the same power rating as a floorstanding speaker. It is whether its tweeter has sufficient durability and protection for its intended use.
This is one reason I have been considering replacing the entire front speaker system with JBL Studio 698 floorstanding speakers and a matching JBL Studio 665C center.
## Earlier Polk forum discussions
I have discovered that similar concerns were being discussed years ago.
**May 2022 – Dead tweeters on one month old R700's**
https://forum.polkaudio.com/discussion/comment/2684240
In this discussion, another R700 owner describes losing both tweeters during louder listening while the bass and midrange drivers continued working.
Polk supplied replacement tweeters.
The owner later reported that a Polk technician had mentioned a batch of defective tweeters.
Another participant also suggested checking the crossover for damaged resistors.
Related comment:
https://forum.polkaudio.com/discussion/comment/2684246
**June 2023 – Polk R700 Polarity & other issues**
https://forum.polkaudio.com/discussion/comment/2731332
This discussion was particularly interesting to me.
The author, HalfOhm, describes R700 speakers with disappointing bass balance and excessively prominent midrange and treble.
He also reports that changing polarity made the upper frequencies sound smoother.
Most importantly, he contacted Polk Audio about the internal polarity arrangement and reported that Polk confirmed the woofers were intentionally connected with opposite electrical polarity relative to the midrange and tweeter section because of the crossover design.
This is remarkably similar to the explanation my distributor eventually received from Polk.
These discussions make me question whether the issues I have experienced are really isolated incidents.
## What I would like to discuss
I would particularly like to hear from other R700 owners and technically experienced members about the following:
1. Have you experienced Pinnacle Ring Radiator tweeter failures during louder listening?
2. Do you believe the R700 tweeter receives excessive power relative to its capabilities?
3. Has anyone measured the crossover's tweeter circuit or investigated whether greater attenuation or protection would improve reliability?
4. Has Polk made any changes to the tweeter or crossover since the problems discussed in 2022?
5. Have Legend L400 owners experienced similar issues with the Pinnacle Ring Radiator tweeter?
6. Has anyone received a detailed technical explanation from Polk Audio about repeated tweeter failures?
I am not asking everyone to agree with me.
I have spent considerable time investigating these problems and have reached my own conclusion based on eight pairs of failed tweeters, different amplifiers, polarity experiments and crossover adjustments.
**My conclusion is that the Pinnacle Ring Radiator tweeter is not sufficiently robust for the output capability of the R700 during louder listening.**
I would welcome a serious technical discussion, including evidence that challenges my conclusion.
Thank you for reading.
Comments
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These failures have all occurred while you are operating the speakers with external EQ? How do you know the tweeters aren't being driven harder through that EQ to compensate for the acoustic characteristics of your room? Have you run pinknoise sweeps of your room to see if there are some sort of high frequency suckouts that the EQ is having to compensate for?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 -
Did Polk engineers design the tweeter? Or is it an off-the-shelf unit from Seas or Tymphany/Peerless?
Edit: Also do any of the diaphragms look distorted?Don't take experimental gene therapies from known eugenicists. -
I have some more basic questions.
- What volume level?
- How big is your room? Dimensions.
- Listening distance.
- Have you ever had satisfactory performance with this system and different speakers?
- Is your room highly damped?
- What kind of audio are you playing?
- Are the tweeters completely dying, or are you cooking them? Are you detecting a nasty fishy smell? (from the tweeters)
Your NAD looks pretty capable spec wise. Gut feeling here without the above info yet is that the volume is simply too high for how you're set up, and you're pushing the tweeters too much with the EQ to compensate for something else.
Polk speakers are not known for weak performance in the high frequency range. Garden's question is interesting. I've only ever had to work with bass suckout, but some high frequency loss somewhere seems possible, though I can't think of a situation where I've experienced it.
Is your room highly damped?
What kind of audio are you playing?
