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GR Research Klipsch RP-600M Upgrade Review (speaker)

Rate this speaker mod:

  • 1. Poor (headless panther)

    Votes: 10 5.2%
  • 2. Not terrible (postman panther)

    Votes: 40 20.9%
  • 3. Fine (happy panther

    Votes: 118 61.8%
  • 4. Great (golfing panther)

    Votes: 23 12.0%

  • Total voters
    191

tvih

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Lots of padding. GR has to recoup R&D and make a profit as a biz and they like to do this by padding the parts rather than selling just the crossover design.

If for 2 channel, Just use PEQ. The directivity is already pretty good so eq handles the responce mod easily.
Heh, yeah, while this is indeed an upgrade, aside from using free computer EQ for the same money you could buy a miniDSP 2x4 HD and get proper room correction and sub integration. Well ok, it wouldn't cover the cost of the mic, but even so.
 

Laserjock

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These are $700 plus tax. , I paid 300 plus 244 for kit. Have seen zero dbr62 reference on the used market. Trust me, I’ve looked.


Used RP600M with GR Kit $544

Reserve r200 $749
(never seen used) even more beaming than 600M
Selah DIY $630 starting if not more now with the pandemic for the kit without no MDF or flatpack
Q350 seen used for $700
in my area quite a bit of ringing from 500 to 1K, distortion is horrible when turned up starting at 100hz
Airmotive t2+ $1000 and is a tower
r100 $649 closer in price but quite a bit of distortion
Monolith 365IW In wall speaker?!?!?! really?
Revel m16 $1000
RP600m II $749

An old post but doesn’t say they have sold yet..
 

Keith Conroy

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This is a review of a Klipsch RP-600M which has been upgraded to a new crossover, binding posts and "No Rez" by GR Research. The kit costs US $244.
View attachment 215422

OK, so there is nothing externally which is different. :) I can't open the unit to show the different bits but here is the back with new binding posts (two are in parallel):
View attachment 215423

I performed all of my testing using the standard binding post.

My old review of RP-600M did not have the latest measurements so what you see is me adding those measurements.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

Reference axis is the tweeter.

Klipsch RP600M With GR Research Mods Measurements
I am going to contrast the stock version with the new. The former will always be on the left. Let's start with the all important spin/frequency response:

View attachment 215424

The stock version is fatally flawed in crossover region with that large hole. GR Mod uses a first order (?) filter to make the two drivers roll off slower and thereby, filling that whole. This gives us a much more flat on-axis response. There is a cost though in sensitivity which drops by 3 or so dB.

We can see the correction better in near-field measurement:
View attachment 215426

There were to port/cabinet resonances in the stock version which are gone now. Whether this is due to padding being different, I can't tell. But it is certainly welcome.

The fix naturally improves the early window response:
View attachment 215427

And with it, predicted in-room response:
View attachment 215428

So very good job there. Let's now look at distortion. This was tricky as I had to match levels. Doing so with speakers of different response is non-trivial but I got close:

View attachment 215429

At 86 dBSPL above, it is hard to see much of a difference. Going up to 96 dB gives us more data:

View attachment 215430

Stock unit has that broad distortion hump. That is much reduced with the mod but now there is a sharp resonance. There is some reduction of distortion at the far side of the spectrum with the mod.

Company makes a lot of hay out of CSD waterfalls so let's look at that:
View attachment 215431

Seems like some reduction in resonances. The peak in the stock speaker around 800 Hz is gone which results in less ringing there.

Impedance and phase plots also show similar improvement:
View attachment 215432

Impedance is also brought up a bit which is nice.

I was interested to see the impact on directivity. Alas, my Klippel software is no longer compatible with old files to view/generate them. :( I have to find out why so here are the data for the modded one:

View attachment 215433

We see controlled directivity courtesy of that waveguide although the tweeter does start to beam/narrow. Even prior, we have rather narrow angle which likely helped with extra energy/sensitivity in that region.
View attachment 215434

Vertically we have the standard issues with 2-way design so stay at tweeter height:

View attachment 215435

Listening Tests
I started listening to the stock RP-600M and immediately noticed its brightness and lack of spectrum in mid frequencies. I switched it out for the modded version and improvement was substantial. The sound was tonally very balanced now. I thought the highs were a little unnatural so switched out the speaker for Revel M105. There was too little bass in that smaller speaker to compete so I put it aside and put on the Revel M15. The Revel projected a much larger/diffused sound which I much preferred to the RP-600M. I switched back to it and the vocals seemed to shrink to the middle of the RP-600M cone. This is backed by the directivity plot (which I had not seen at the time).

The dynamics were a bit more limited with the mod due to its lower sensitivity. And by this I mean it started to get distorted a bit less than the stock speaker did. Impact was in bass frequencies which became progressively ugly. That said, this was happening at fairly high playback level and with one speaker. So as a practical matter it should be fine if you have enough amplification power.

Conclusions
The flaw in stock RP-600M is so obvious and so is the solution. It was reassuring to see GR Research correcting the response and smartly using lower order filters as to keep the cost down. The difference is dramatic. I can't listen to the stock version. But with the mod, the combination was definitely a contender. You lose some sensitivity so better have a good sized amplifier. The narrow directivity is not to my taste but may be to yours.

Overall, this is a job well done by GR Research and I am going to recommend it to owners if they are not inclined to use my software EQ fix.

-----------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
Overall this is another one of your technically well done reviews. I think it was a mistake to not show the kit & describe whats in it. To me, this review also shows another important personal point about you. You let the data drive this review. You left politics at the door, which for me is refreshing. You had tested another GR Research product & it did not fair well. Obviously there have been some politics from GR on the internet related to that! So now you tested another new GR product. The data showed an improvement over the stock Klipsch and you reported it as such. Good job, because if your an engineer you have to stay true to the data!
 

abdo123

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Heh, yeah, while this is indeed an upgrade, aside from using free computer EQ for the same money you could buy a miniDSP 2x4 HD and get proper room correction and sub integration. Well ok, it wouldn't cover the cost of the mic, but even so.
I think this is very attractive for home theatre people where you just want to plug something passive to an AVR and enjoy.
 

ZööZ

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I would be interested to hear which passive speakers on this forum measured better than this at the same price range.
Wharfedale Diamond 12.1?

EDIT just realised you propably meant with the mod, without the mod 12.1 has better preference score but worse bass distortion ( only 5") and with sub it has a tad better preference rating even compared to the modded klipsch. no idea how applicable the preference score is in real world especially given the diamonds bbc dip.
 
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tvih

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I think this is very attractive for home theatre people where you just want to plug something passive to an AVR and enjoy.
I don't think most people like that would even notice the difference or care about it. And if they did then it goes back to just buying a better speaker to begin with. Swapping out crossovers seems poorly suited for someone with a plug and play mentality.

Or room correction by the AVR might fix the problem, but then the EQ would make the upgrade itself pointless anyway.
 
OP
amirm

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I think it was a mistake to not show the kit & describe whats in it.
I don't have access to the kit. The owner did the mod and I don't want to disassemble the speaker just to take a picture. Company has a video on the mod.
 

beaRA

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I enjoyed the KEF Q350, it has much better bass in play than the testing suggests. Nice tonality with a very mellow trend. Most mellow KEF I have used.

I thought the R200 was POS. Worst speaker I have tested over $300 maybe ever.
I personally can't stand that tweeter nor the horrible drop off in the off axis high frequency range that starts at 5k. No air, no vibrancy, no excitement. Oddly though well in the past in a different house I did kind of like the L200. Possible change in taste, possibly the change in rooms which are meaningfully different, maybe mine where defective but Polk suggested no. I will never know. I did not use the L200 very much, maybe an hour or two. I was just borrowing them for a day or so.

Revel M16.
Best speaker I have used that costs $1000 or less.
I vastly preferred to some strong competitors such as the KEF R3 amoung others. Note "vast" is becoming a rare term in my vocab as many things are close but like some others that Revel sound just got me. So good for the money.
I think you are downplaying the possibility of your R200 pair being defective too much. Measurements of that tweeter shared in your thread by many users (including myself) don't match your own. It could be the directivity is still not to your taste, but unequivocally calling it a POS without the full context of your situation is not fair.
 

dfuller

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The Klipsch are built for modern electronic music where tone and accuracy aren't as important.
I despise this line of thinking - why would it be less important by genre? It mostly just sounds like "oh, that isn't real music, you don't need good speakers for that".
 

ROOSKIE

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Here is a previous iteration of the speaker, the RB-5.

View attachment 215552

View attachment 215553

It was much better than this (unmodified) version and it is certainly good to see the company fix what they changed in the new version. I think Amir and everyone got it right in the old review and in those similar to it. The speaker was modified to stand out in show rooms. Once they were being sold at Best Buy along with all sorts of other speakers, getting it sold by any means was the goal. They know exactly what they are doing. Hopefully things are changing now. Seems that there was pressure, which shows sites like this are working.
I beleive that knock on these is the horn so horn sounding.
I think you are downplaying the possibility of your R200 pair being defective too much. Measurements of that tweeter shared in your thread by many users (including myself) don't match your own. It could be the directivity is still not to your taste, but unequivocally calling it a POS without the full context of your situation is not fair.
You are correct.
I should not have said POS.
I will actually edit that.
Was having a triggered flashback to all the time I spend on them and them dealing with Polk. Who were nice but in 2022 customer service is tough to deal with due to such distances and device barriers and more.
 

ta240

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What is the consensus on why the speakers were originally designed that way? Did they cut corners and that is just what they ended up with? Or was it by design to make them stand out in large stores as being lively and make them sound like they were more efficient?
 

USER

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I beleive that knock on these is the horn so horn sounding.

They sound good. I was anticipating them being bad like this last version and went in with prejudice but I had to admit they sounded good. Indeed the reviews I've read were positive. I heard them at a friend's house when I was setting them up for him (hence the measurements) and I brought over the Dennis Murphy Affordable Accuracy Monitors as a reference and for fun and we both preferred them. Nonetheless the Klipsch speakers were fine.
 
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Doodski

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I am still wondering about the Axiom M3. Axiom works with the NRC to measure and develop their speakers. You get international shipping. You get real veneer. And it's about $600.

I sound like a an Axiom salesman LOL. But they seem too good to be true.
I retailed Axiom for a couple of years and they sold well against Paradigm, Klipsche and Polk.
 

Jim Shaw

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I despise this line of thinking - why would it be less important by genre? It mostly just sounds like "oh, that isn't real music, you don't need good speakers for that".
It is painful to hate and despise, eh? I suspect you are intimidated by those who prefer acoustically produced music. Maybe you don't realize it, or don't want to. There's an important difference between electronic and 'manufactured' music -- and acoustical music. The difference is that we don't have any frame of reference or calibration for what manufactured music should sound like. With acoustic music, regardless of taste, we can hear the music performed live and form a judgment as to its similarity. Manufactured music is the result of loudspeakers and sound mixers in the performance process. There's no telling how it was made or what was done to it before we first hear it.

For example, I have a very good idea of what a wooden guitar with gut or metal strings sounds like. I don't know what a synthesizer sounds like. It depends.
I know a string double bass. I don't know what an amplified bass guitar should sound like.
I know what a grand piano sounds like, as well as an old Rhodes. I don't know what a custom synthesizer piano must be like. It depends
I know what tympani (kettle drum set) sounds like. I don't know what an electronic kick drum must sound like. It depends.

It's not just taste. I cannot dance to Beethoven. I can to EDM. I can't take EDM seriously. It wasn't meant to be; it's for dancing and fun.

The audiophiles I pay attention to will play acoustic music because they can calibrate it to what their ear remembers. That's pretty hard to do with music that was manufactured in digital circuits. Then perhaps, they put on Avalon to make babies...
 

uwotm8

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Been dying to hear a pair of Revels!
I'd like to hear them too because for now - if we don't mind some exotic 100k+ systems - only Dynaudio really got me (those ones with canonic 3" voice coil and inner magnets woofers - same size with budget 1" coil such as LYD 5, X12 etc can't do that in-house hammering bass). KEFs, Focals etc - "well, these are speakers, ok":)
 
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hestejoe

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Overall a good mod. I wonder how a purely EQ adjustment would fair; the vertical performance of this mod is a bit worse than stock, so using this mod in the near-field may not be best.

Could this be a unique version to compare the original, the hardware modded and an EQ'ed based on the measurements? I would surely be very interested if @amirm could have the time to do so. At least it wouldn't drain his wallet.
 

voodooless

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So guess what someone with real knowledge of filters could do to these
For example, I have a very good idea of what a wooden guitar with gut or metal strings sounds like.
But do you know if the artist wanted you to actually hear a wooden guitar as it should sound? Or differently? Even for real live acoustic recordings it’s all about interpretation of the recording. A microphone captures sound differently from your ears. It has a different profile and many times a totally different location. It’s all just an elaborate illusion regardless of what music is recorded.
I cannot dance to Beethoven.
Oh but you can ;)

The audiophiles I pay attention to will play acoustic music because they can calibrate it to what their ear remembers. That's pretty hard to do with music that was manufactured in digital circuits. Then perhaps, they put on Avalon to make babies...
So what? It’s whatever the artist makes… some art is photo realistic, others looks like some blue sneers on a yellow background… some like this, others like that… both works of art need a proper room and lighting to reach their full potential.
 

dorirod

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These are $700 plus tax. , I paid 300 plus 244 for kit. Have seen zero dbr62 reference on the used market. Trust me, I’ve looked.

Amazon has a pair used for $490
 

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