CRS+ (1989) Driver Phase Plug And Aluminum Tweeter Plate Modifications
DarqueKnight
Posts: 6,765
Introduction
The plastic face plates of the RD0198 tweeters in my black oak SDA CRS+ speakers were replaced with aluminum face plates. This resulted in an overall improvement in sound quality with greater clarity, detail, and image focus. Replacing the original MW6510 and MW6511 drivers with phase plugged versions resulted in a loss of high frequency detail and a loss of image focus, particularly in the center, where the previous sharply defined layering of sound images was replaced by a more diffuse collection of sound images and contraction of front to back depth.
Figure 1. Phase plugged MW6510s, MW6511s, and aluminum tweeter face plates.
Prior Modifications
These CRS+s have the following prior modifications:
Figure 2. Custom printed circuit boards with Mills MRA-12 resistor, AudioCap and SonicCap film capacitors, and Jantzen inductors.
Figure 3. Solen perfect lay 14 AWG SDA inductors.
Figure 4. Steel retainer rings and brackets for drivers, passive radiator, binding post cup, and tweeters.
Figure 5. Cardas 15.5 AWG internal wiring.
Figure 6. Dreadnought AI-1 Non-Common Ground Amplifier Interface with 1000 VA Avel-Lindberg low noise audio grade 1:1 isolation transformer and Cardas 9.5 AWG cables. The Dreadnought also works very well with common ground amplifiers.
Figure 7. RD0198 silk dome tweeters (crossovers have the CRS+ "TL" modification").
Figure 8. Cardas CCGR-S binding posts.
Evaluation Setup
The CRS+s were taken out of storage and set up in my home theater system. These speakers were previously used in my office rig at work. They, and their associated electronics, were put in storage in May 2021 when I began working from home. Prior to the tweeter face plate change, listening was done for one week in order to re-familiarize myself with the CRS+s' sound. The associated electronics in the home theater system were as follows:
1. Bryston BDP-1 digital music player.
2. Oppo UDP-205 universal disc player used as a DAC.
3. Yamaha CX-A5100 preamplifier-processor in "straight through" (no EQ) configuration.
4. Adcom GFA-565se power amplifier (350 wpc into 4 ohms).
5. PS Audio P5 AC Regenerator for BDP-1 digital player and Oppo UDP-205 universal disc player.
6. PS Audio P10 AC Regenerator for Adcom GFA-565se power amplifier.
7. Douglas Connection DCF-92 speaker sables.
8. Signal Cable Silver Resolution XLR interconnects (preamp To power Amp).
9. Revelation Audio Labs Prophecy Cryo-Silver Dual-Conduit USB cable (digital player to DAC).
10. Monster Cable Z200i XLR interconnects (DAC analog out to preamp processor).
11. PS Audio AC-5 power cords for AC Regenerators.
12. PS Audio Statement SC power cords for all electronic components.
Figure 9. Response measurements were taken with OmniMic software, with the microphone 8 feet from the center of the speaker plane and 42 inches from the floor (ear height). The listening position was 12 feet from the center of the speaker plane. The microphone remained in position during listening evaluations.
Individual tweeter and driver frequency response, phase angle, and electrical and mechanical parameters (Thiele-Small) were taken with Dayton Audio DATS VS software.
The listening/measurement regimen was as follows:
1. CRS+ speakers taken out of storage and listened to for seven days.
2. Room response measurements done with speakers at end of seven day listening period.
3. Tweeter measured with plastic and with metal face plates.
4. Listening evaluation done with metal tweeter face plates.
5. Room response measurements done with speakers after metal tweeter face plates installed.
6. Listening evaluation done with phase plugged drivers installed.
7. Room response measurements done with phase plugged drivers installed.
8. Listening evaluation done with original drivers re-installed.
Figure 10. The CRS+s were spaced 43.25 inches apart (inner side to inner side). The TV served as the "rear wall". The CRS+'s rears were 5 inches from the TV screen. It would have been better to take the LSiM 707s out of the room...but then I remembered the tedious toe-in and leveling ritual using laser levels and trigonometric math. It also would have been better to set up the CRS+s in my "big rig" with the nice Pass Labs electronics...but then I remembered that The Monoliths don't like to have their cables disturbed. For the uninitiated who don't know what "The Monoliths" are, see figure 11 below.
Figure 11. "The Monoliths" - SDA SRS 1.2TL True Stereo loudspeakers.
Figure 12. The Monoliths' right speaker cable configuration. They don't like having their cables messed with.
Listening Evaluations
The baseline configuration was with the original MW6510s, MW6511s, and RD0198 tweeters with plastic face plates. With this configuration the speakers sonically "vanished". There were no artifacts of sound emanating from a loudspeaker whatsoever. There were just focused and stable sound images suspended in space extending beyond the front and rear of the speaker plane and beyond the outside edges of the cabinets. The center stage was sharply defined with excellent layering of sound images front to rear.
When the plastic tweeter face plates were replaced with the aluminum plates, there was further refinement in sound quality: More sharply defined bass articulation and bass growl. More detail in background percussion instruments. More overall clarity and detail.
When the original drivers were replaced with the phase plugged drivers, there was a loss of clarity and detail. The center images became less sharply defined and diffuse. Images that were previously projected 3 feet forward of the speaker plane receded to the speaker plane. There was less detail in background instruments such as small percussion instruments. Piano notes lost some of their sparkle and percussive qualities. My results are the opposite of what was achieved with conventional Polk speakers (5B, 8TL, etc.) and with an experimental setup done by @xschop with CRS+ crossovers and drivers in horizontal MTM configuration.
Re-installing the original drivers restored the "magic". In the good old days when Polk's engineering department was easily and readily accessible, I would have asked them to comment on my results. However, those days are long gone.
Figure 13. Anodized aluminum face plate installed. Such Good Sound!
Figure 14. Phase plugged drivers installed.
The plastic face plates of the RD0198 tweeters in my black oak SDA CRS+ speakers were replaced with aluminum face plates. This resulted in an overall improvement in sound quality with greater clarity, detail, and image focus. Replacing the original MW6510 and MW6511 drivers with phase plugged versions resulted in a loss of high frequency detail and a loss of image focus, particularly in the center, where the previous sharply defined layering of sound images was replaced by a more diffuse collection of sound images and contraction of front to back depth.
Figure 1. Phase plugged MW6510s, MW6511s, and aluminum tweeter face plates.
Prior Modifications
These CRS+s have the following prior modifications:
Figure 2. Custom printed circuit boards with Mills MRA-12 resistor, AudioCap and SonicCap film capacitors, and Jantzen inductors.
Figure 3. Solen perfect lay 14 AWG SDA inductors.
Figure 4. Steel retainer rings and brackets for drivers, passive radiator, binding post cup, and tweeters.
Figure 5. Cardas 15.5 AWG internal wiring.
Figure 6. Dreadnought AI-1 Non-Common Ground Amplifier Interface with 1000 VA Avel-Lindberg low noise audio grade 1:1 isolation transformer and Cardas 9.5 AWG cables. The Dreadnought also works very well with common ground amplifiers.
Figure 7. RD0198 silk dome tweeters (crossovers have the CRS+ "TL" modification").
Figure 8. Cardas CCGR-S binding posts.
Evaluation Setup
The CRS+s were taken out of storage and set up in my home theater system. These speakers were previously used in my office rig at work. They, and their associated electronics, were put in storage in May 2021 when I began working from home. Prior to the tweeter face plate change, listening was done for one week in order to re-familiarize myself with the CRS+s' sound. The associated electronics in the home theater system were as follows:
1. Bryston BDP-1 digital music player.
2. Oppo UDP-205 universal disc player used as a DAC.
3. Yamaha CX-A5100 preamplifier-processor in "straight through" (no EQ) configuration.
4. Adcom GFA-565se power amplifier (350 wpc into 4 ohms).
5. PS Audio P5 AC Regenerator for BDP-1 digital player and Oppo UDP-205 universal disc player.
6. PS Audio P10 AC Regenerator for Adcom GFA-565se power amplifier.
7. Douglas Connection DCF-92 speaker sables.
8. Signal Cable Silver Resolution XLR interconnects (preamp To power Amp).
9. Revelation Audio Labs Prophecy Cryo-Silver Dual-Conduit USB cable (digital player to DAC).
10. Monster Cable Z200i XLR interconnects (DAC analog out to preamp processor).
11. PS Audio AC-5 power cords for AC Regenerators.
12. PS Audio Statement SC power cords for all electronic components.
Figure 9. Response measurements were taken with OmniMic software, with the microphone 8 feet from the center of the speaker plane and 42 inches from the floor (ear height). The listening position was 12 feet from the center of the speaker plane. The microphone remained in position during listening evaluations.
Individual tweeter and driver frequency response, phase angle, and electrical and mechanical parameters (Thiele-Small) were taken with Dayton Audio DATS VS software.
The listening/measurement regimen was as follows:
1. CRS+ speakers taken out of storage and listened to for seven days.
2. Room response measurements done with speakers at end of seven day listening period.
3. Tweeter measured with plastic and with metal face plates.
4. Listening evaluation done with metal tweeter face plates.
5. Room response measurements done with speakers after metal tweeter face plates installed.
6. Listening evaluation done with phase plugged drivers installed.
7. Room response measurements done with phase plugged drivers installed.
8. Listening evaluation done with original drivers re-installed.
Figure 10. The CRS+s were spaced 43.25 inches apart (inner side to inner side). The TV served as the "rear wall". The CRS+'s rears were 5 inches from the TV screen. It would have been better to take the LSiM 707s out of the room...but then I remembered the tedious toe-in and leveling ritual using laser levels and trigonometric math. It also would have been better to set up the CRS+s in my "big rig" with the nice Pass Labs electronics...but then I remembered that The Monoliths don't like to have their cables disturbed. For the uninitiated who don't know what "The Monoliths" are, see figure 11 below.
Figure 11. "The Monoliths" - SDA SRS 1.2TL True Stereo loudspeakers.
Figure 12. The Monoliths' right speaker cable configuration. They don't like having their cables messed with.
Listening Evaluations
The baseline configuration was with the original MW6510s, MW6511s, and RD0198 tweeters with plastic face plates. With this configuration the speakers sonically "vanished". There were no artifacts of sound emanating from a loudspeaker whatsoever. There were just focused and stable sound images suspended in space extending beyond the front and rear of the speaker plane and beyond the outside edges of the cabinets. The center stage was sharply defined with excellent layering of sound images front to rear.
When the plastic tweeter face plates were replaced with the aluminum plates, there was further refinement in sound quality: More sharply defined bass articulation and bass growl. More detail in background percussion instruments. More overall clarity and detail.
When the original drivers were replaced with the phase plugged drivers, there was a loss of clarity and detail. The center images became less sharply defined and diffuse. Images that were previously projected 3 feet forward of the speaker plane receded to the speaker plane. There was less detail in background instruments such as small percussion instruments. Piano notes lost some of their sparkle and percussive qualities. My results are the opposite of what was achieved with conventional Polk speakers (5B, 8TL, etc.) and with an experimental setup done by @xschop with CRS+ crossovers and drivers in horizontal MTM configuration.
Re-installing the original drivers restored the "magic". In the good old days when Polk's engineering department was easily and readily accessible, I would have asked them to comment on my results. However, those days are long gone.
Figure 13. Anodized aluminum face plate installed. Such Good Sound!
Figure 14. Phase plugged drivers installed.
Proud and loyal citizen of the Digital Domain and Solid State Country!
Comments
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Measurements
[Note: Right clicking on the plots and opening them in a new tab will show the plots in larger detail.]
Figure 15. Frequency response of baseline configuration with original drivers and plastic tweeter face plate.
Figure 16. Frequency response of configuration with original drivers and aluminum tweeter face plate.
Figure 17. Frequency response of configuration with phase plugged drivers and aluminum tweeter face plate.
Two phase plugged MW6510s were purchased from @xschop. Two of my extra MW6511s were sent to @xschop for phase plug modification. Before and after frequency and phase angle plots of the MW6511s are shown in figures 18-21. Beginning at 2 kHz, there is a reduction in phase angle and impedance.
Figure 18. MW6511 #1 frequency response and phase measurement before phase plug modification.
Figure 19. MW6511 #1 frequency response and phase measurement after phase plug modification.
Figure 20. MW6511 #2 frequency response and phase measurement before phase plug modification.
Figure 21. MW6511 #2 frequency response and phase measurement after phase plug modification.
Of course, I was not able to do before/after phase and frequency plots of the MW6510 drivers. I did compare plots of the phase plugged MW6510s to the CRS+'s original 6510s. The results were similar to what is shown in figures 18-21.
Figure 22. Left RD0198 tweeter frequency response and phase measurement with plastic face plate.
Figure 23. Left RD0198 tweeter frequency response and phase measurement with aluminum face plate.
Figure 24. Right RD0198 tweeter frequency response and phase measurement with plastic face plate.
Figure 25. Right RD0198 tweeter frequency response and phase measurement with aluminum face plate.
Figure 26. The CRS+s have a metal mesh grille over the rear-firing passive radiator. That made it inconvenient to do the finger "pressure test" for leaks.
After removing the passive radiator grille, pressing on the passive radiator resulted in the drivers bulging out and talking two seconds to come to rest (counting 1001, 1002). The drivers did not return to their original position until the passive radiator was released. The results were the same for the original and phase plugged drivers.
Conclusion
Everyone's ears, systems, room, and SDAs are different. If you have the extra cash, extra drivers, and extra time to try the phase plug modification, I wouldn't discourage it. You might like it. I don't expect that anyone would be disappointed with the aluminum face plate modification.Post edited by DarqueKnight onProud and loyal citizen of the Digital Domain and Solid State Country! -
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The one person that can post and make it feel like old times..
So the phase plug drivers are ones you modified? I have the extra drivers but not a modification I have the desire to try, nor the foam on the inside of the baskets, I highly commend you on giving this a shot, and thank you for giving the time to give us a wright up..
I as well love the aluminum tweeter face plates..
Thanks Ray!! -
Thanks for the write up Ray, as always your dedication to excellent reviews is outstanding.
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Ray, great write up and experimentation.
At your leisure, can you check the polarity of the 6510's?
It dawned on me I did not check polarity as I got them from another member and put on storage after plugging those awhile back.
Of the 30 or so drivers I've plugged/ fixed shifted magnets, I have had 2 drivers that came with the magnets installed flipped from factory.
From my notes on the CRS+ build the stereo driver is crossed at 2k Hz and the SDA driver at half that. Scratching my head why the 3khz anomaly and 7khz anomaly. Diffraction possibly?
Don't take experimental gene therapies from known eugenicists. -
So the phase plug drivers are ones you modified?
No. The modified MW6510s I bought from@xschop. I sent two of my spare MW6511s to him for modification.
Proud and loyal citizen of the Digital Domain and Solid State Country! -
At your leisure, can you check the polarity of the 6510's?
It dawned on me I did not check polarity as I got them from another member and put on storage after plugging those awhile back.
I used a 1.5V AA battery to check polarity. The cones moved up when the positive terminal of the battery was connected to the positive terminal of each 6510. The cones moved down when the positive terminal of the battery was connected to the negative terminal of each 6510.
Proud and loyal citizen of the Digital Domain and Solid State Country! -
Good deal. Did you check your 6511s also?
Also after install, did your 6511's cones come back to rest at the base of the plugs?
I posted about that when I plugged them and don't see that very often as if they were either manufactured that way or sat in storage a long time while face-up.
Don't take experimental gene therapies from known eugenicists. -
The polarity of the 6511s is correct.Also after install, did your 6511's cones come back to rest at the base of the plugs?
I posted about that when I plugged them and don't see that very often as if they were either manufactured that way or sat in storage a long time while face-up.
At rest, my 6511s look like the ones in your picture, showing about a quarter inch of flat metal below the cone. The 6510s only show the cone when at rest.
My 6511s:
My 6510s:
Proud and loyal citizen of the Digital Domain and Solid State Country! -
Thanks for taking the time to do this testing and listening Ray. It is very interesting!
A few things come to mind:
1) With the very real and significant (but not large) reduction in impedance around the crossover point area, would it be possible that the electrically conductive aluminum phase plug on top of the pole piece could be acting as a shorting ring with an overhung voice coil like this?
2) There is a pretty noticeable effect on the frequency response of the speakers and there seems to be a greater deviation (reduction in sPL) the more above 3kHz you go which is all tweeter frequencies not MW frequencies, with the stated by Polk crossover frequency of 2.5kHz. It seems to me that this is probably destructive interference caused by time delayed reflections of tweeter frequencies off of the 2 phase plugs. With the geometry of the CRS+ driver positions, this could be a greater problem than in Monitor series speakers. In my case with my 7Bs, it just so happened that I had installed anti diffraction wool pieces around my tweeter and MW that were custom made for me by VR3 prior to doing the phase plug mod.
3) I got greatly improved timbre and realism of instruments particularly cymbals and piano and I continue to be ecstatic with the improvements. @Jazzhead had a similar experience. In both of our cases tweeter diffractions off the phase plugs being an issue were probably minimalized, in his case because of the RTA12 tweeter separation and setback with the anti diffraction piece and in my case because of the anti diffraction wool.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 -
After reading the superb presentation of the intricacies involved in this undertaking by @DarqueKnight and supporting fellow Polkies, my mind went to one of my favorite TV Series of the "good old days".
That TV series is Mission Impossible on TV from 1996 - 1973. Certainly a great effort in this thread, and "Mission Impossible" perfectly describes the effort. Mr. Phelps and cast would be pleased.
"Sometimes you have to look to the past to understand where you are going in the future"Anger is just anger. It isn’t good. It isn’t bad. It just is. What you do with it is what matters.
You can use it to build or to destroy. You just have to make the choice. Jim Butcher
Harry / Marietta GA -
Gardenstater wrote: »1) With the very real and significant (but not large) reduction in impedance around the crossover point area, would it be possible that the electrically conductive aluminum phase plug on top of the pole piece could be acting as a shorting ring with an overhung voice coil like this?
That is a plausible explanation. One thing is certain: there is increased electrical conductivity coming from somewhere. A big chunk of conductive metal in the middle of the voice coil is a likely suspect.Gardenstater wrote: »2) There is a pretty noticeable effect on the frequency response of the speakers and there seems to be a greater deviation (reduction in sPL) the more above 3kHz you go which is all tweeter frequencies not MW frequencies, with the stated by Polk crossover frequency of 2.5kHz. It seems to me that this is probably destructive interference caused by time delayed reflections of tweeter frequencies off of the 2 phase plugs. With the geometry of the CRS+ driver positions, this could be a greater problem than in Monitor series speakers. In my case with my 7Bs, it just so happened that I had installed anti diffraction wool pieces around my tweeter and MW that were custom made for me by VR3 prior to doing the phase plug mod.
I agree that there is some type of acoustical destructive interference. Also, the lower impedance of the drivers at higher frequencies is allowing them to operate beyond their design specification with this crossover. In that regard, there is likely some electrical destructive interference with the tweeters. This extended high frequency response of the drivers might also be responsible for the reduction in imaging precision. Some crossover adjustments are probably needed to bring the overall response back into balance.Gardenstater wrote: »3) I got greatly improved timbre and realism of instruments particularly cymbals and piano and I continue to be ecstatic with the improvements. @Jazzhead had a similar experience. In both of our cases tweeter diffractions off the phase plugs being an issue were probably minimalized, in his case because of the RTA12 tweeter separation and setback with the anti diffraction piece and in my case because of the anti diffraction wool.
I don't doubt that excellent results were achieved with conventional speakers. This modification may not be suitable for SDAs unless some crossover modifications are made to fully accomodate it. All I can say for certain is that the phase plug modification did not work with this particular pair of SDAs.
Here are the frequency and phase plots for the 6510s. Since I purchased the 6510s with phase plugs, I could not do a before and after measurement as I did with my 6511s. The best I could do is compare the plugged 6510s to the CRS+'s original 6510s.
Left CRS+ original MW6510:
Left phase plugged MW6510:
Right CRS+ original MW6510:
Right phase plugged MW6510:
Harmonic distortion plots:
Black = Frequency Response
Red = 2nd Harmonic
Purple = 3rd Harmonic
Green = 4th Harmonic
Light Blue = 5th Harmonic
Dark Blue = Sum of 2nd-5th Harmonics
Harmonic distortion with plastic tweeter face plate:
Harmonic distortion with metal tweeter face plate:
Harmonic distortion with metal tweeter face plate and phase plugged drivers:
Proud and loyal citizen of the Digital Domain and Solid State Country! -
Of all the SDA's, the CRS tweeters are furthest from the stereo driver. When I experimented years ago on a set, I moved the tweeters as close as I could to the stereo driver and got much better imaging.
I also moved the MWs closer together, but not touching each other, as the sound stage seemed unnaturally wide with them spaced like factory.
That said, I'm still looking forward to what the plugged drivers sound like in 2Bs with their MWs butted together.
Don't take experimental gene therapies from known eugenicists. -
I think you should move on to Cerwin-Vega’s…
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I think F1 is hoarding them all. Chances are I'll find another set of Mon 10s to convert and experiment on. The bass in those put the CRS to shame and are more forgiving in placement.Don't take experimental gene therapies from known eugenicists.
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I know it's not a perfect idea, but I'd love to measure my 1C when done, so... maybe I and someone with unmolested midwoofers can somehow do a comparable measurement attempt from afar?
I used plastic for my 5B phase plugs, and was going to try it on my Monitor 12, too. I'd love to help add to the testing pool for different models.
And my replacement tweeter plates are plastic, too.
Super happy to help gather useable info!
The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * custom 5B on a system for my Dad * Ye Olde college stereo in the garage -
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@plastic_avatar Don't forget to use anti-diffraction wool in appropriate amounts and location on your baffle but I believe you already had plans to do so.
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 -
Let's be civil in our pursuit of audio bliss. For everything that we individually cherish, there are individuals and groups that would make mockery of it.Proud and loyal citizen of the Digital Domain and Solid State Country!
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DarqueKnight wrote: »...pursuit of audio bliss...
I'm insanely curious to seek out that deep center image you speak of.
I didn't pay attention to how forward presentations were tonight (still working through the wow factor of how much clearer and expansive the 1C are compared to anything I'm familiar with).
Could you share at least 1 recording that gives you that sense of depth and clarity of presence? A short note on your description of what we should listen for on our setups would be great, too.
I think having the written expectation of what to look for while I listen to a particular song is a missing piece to the evaluation puzzle.
I'd appreciate the insight and direction.The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * custom 5B on a system for my Dad * Ye Olde college stereo in the garage -
plastic_avatar wrote: »DarqueKnight wrote: »...pursuit of audio bliss...
I'm insanely curious to seek out that deep center image you speak of.
Could you share at least 1 recording that gives you that sense of depth and clarity of presence? A short note on your description of what we should listen for on our setups would be great, too.
I think having the written expectation of what to look for while I listen to a particular song is a missing piece to the evaluation puzzle.
There is a list of SDA "showcase" recordings here:
https://forum.polkaudio.com/discussion/22736/sda-playlist/p1
Here is what Herbie Hancock's "Chameleon" (from his "Headhunters" CD) sound like on my hotrodded SDA SRS 1.2TLs.
The song begins with electric bass which is in the center of the speaker plane.
Drums come in at 00:13 three feet behind the electric bass. This sound image comes from behind the rear wall.
Electric guitar starts at 00:35 and is three feet to the left of the left speaker and four feet in front of it. Electric piano starts at 00:54 and is three feet to the right of the right speaker and four feet in front of it.
Synthesizer starts at 01:12 in the speaker plane 1 foot to left of left speaker and 1 foot above the electric guitar image.
Horns start at 01:30 and are at the top of the left speaker directly above the synthesizer, as if the horn players are standing on a platform behind the synthesizer player.
The sound stage on this recording, on my speakers, is crescent shaped and 16 feet wide, 7 feet deep, and 5 feet 4 inches high. The sound images are life size with lifelike sonic "weight" and a sense of space
between instruments. I can turn my head left or right to "look" at a particular sound image and the other
images will remain firmly in their places, just like real performers on a real stage.
Electrical noise in the music signal and undamped, unwanted, mechanical vibrations smear, diminish, and obscure spatial detail. As more electrical and mechanical noise is removed, the spatial properties in the recording become clearer and more detailed.
As for what to listen to in your setup...this is personal depending on your listening tastes. I listen primarily to instrumental jazz. I know what real instruments sound like and I have heard real acoustic and electric instruments played in a small intimate setting many times. This is the sound I want to get close to in my listening room. In addition to sound instruments fixed firmly in place in the sound stage, I want to hear sonic cues reminiscent of a live performance: the sound of the wood in a double bass, sound of plucked strings on the double bass, the silky smooth sound of a saxophone reed, yet with a raspy undertone, the airy, ticklish sound of piano keys, the stick and skin sounds of the drums, the serrated rumble and growl of electric bass, etc.
Proud and loyal citizen of the Digital Domain and Solid State Country! -
I just became a little angry at my RTAs after reading that ^^^ and then listening to "Chameleon" on them.DarqueKnight wrote: »...
When the plastic tweeter face plates were replaced with the aluminum plates, there was further refinement in sound quality: More sharply defined bass articulation and bass growl. More detail in background percussion instruments. More overall clarity and detail.
...
Interesting a tweeter mod results in better bass.Brian
One-owner Polk Audio RTA 15TL speakers refreshed w/ Sonicap, Vishay/Mills and Cardas components by "pitdogg2," "xschop" billet tweeter plates and BH5 | Stereo REL Acoustics T/5x subwoofers w/ Bassline Blue cables | Rogue Audio Cronus Magnum III integrated tube amp | Technics SL-1210G turntable w/ Ortofon 2M Black LVB 250 MM cart | Sony CDP-508ESD CD player (as a transport) | LampizatOr Baltic 4 tube DAC | Nordost & DH Labs cables/interconnects | APC H15 Power Conditioner | GIK Acoustics room treatments | Degritter RCM -
DK: Thanks for the write-up! That's helpful.
I went through the SDA thread months ago and built 2 playlists to cull songs from that I own for the eval. Not a lot in there that's as detailed as what you gave me up there^ That's *exactly* what I'd love to see on song recommendations.
Again, thank you
The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * custom 5B on a system for my Dad * Ye Olde college stereo in the garage
