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Klipsch RP-600M Speaker Review

amirm

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#1
This is a review and detailed measurements of the Klipsch RP-600M Speaker Review. I purchased them from Amazon a couple of weeks ago. The current cost on Amazon is US $629 including Prime shipping. I however found a refurbished one for $450 I think. It looks brand new in the box though. "RP" stands for Reference Premier so it better do well!

As I have said in my previous reviews of Klipsch speakers, they are a genius in marketing department and that is reflected in the super nice look of RP-600M:

Klipsch RP-600M Bookshelf Speaker Audio Review.jpg

Beauty can be surprisingly skin deep though as one looks at the back and notices thin metal bridging the somewhat crude terminals:

Klipsch RP-600M Bookshelf Speaker Back Panel Connectors Biwire Audio Review.jpg
Wish they had put in just one set of better quality binding posts. It does the job though.

The RP-600M is super popular with tons of bloggers giving it praise mixed with other wording that one cannot make sense out of. Stereophile also reviewed it and Herb Reichert had this to say about their sound:

1584658869816.png


Vibrantly present? We will see about that. :) JA had this to say about the measurements:

1584658938453.png


Interesting that these aspects would translate into what Herb had to say.

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 anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

All measurements are reference to tweeter axis with the grill removed. Frequency resolution is 2.7 Hz. Over 1000 measurement points were used to assure high precision in higher frequencies.

Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker can be used. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

Klipsch RP-600M Bookshelf Speaker Spinorma CEA-2034 Audio Measurements.png


Good grief. Look at how the two drivers are crossed with that giant dip. It seems to me this is on-purpose as all they had to do was to set the crossover frequencies a bit different and the hole would not be this deep. They must think what sells is bass and treble, and damn everything else in the middle.

Directivity (on and off-axis similarity) looks very good though. In theory then, that dip would be one we can fill in with equalization.

This would not be a Klipsch speaker without some terrible peaking although the amount is rather mild here compared to what they could do. Likewise, they publish fantasy stories about sensitivity. As I note, in bass frequencies where you need sensitivity, you still need tons of power. But maybe the highs bother you so much you won't want to turn it up that much!

Predicted in-room response tells us what we already (for good and bad);
Klipsch RP-600M Bookshelf Speaker Spinorma CEA-2034 Predicted In-room Response Audio Measureme...png


Because on and off-axis response is similar, we get the same shape graph as our spinorama on-axis with a bit of tilt down which we can all appreciate.

Early reflections all have the same dip as noted repeatedly:

Klipsch RP-600M Bookshelf Speaker Spinorma CEA-2034 Early Reflections Audio Measurements.png


On many speakers, on-axis is flat in this region and it is off-axis that causes the dip. Here all axis have the same hole.

Impedance predictably dips a lot lower than Klipsch lets on:

Klipsch RP-600M Bookshelf Speaker Impedance and Phase Audio Measurements.png


Distortion shows that the woofer is starting to suffer before it is retired by the tweeter:

Klipsch RP-600M Bookshelf Speaker Ditortion Audio Measurements.png


So maybe that is the reason for not pulling its response up higher? Nah. They wanted this kind of response.

I let you hunt around for resonances in the waterfall:

Klipsch RP-600M Bookshelf Speaker CSD Waterfall Audio Measurements.png


Story is already told on directivity but here are the pretty graphs anyway:

Klipsch RP-600M Bookshelf Speaker Horizontal Contour Audio Measurements.png


Klipsch RP-600M Bookshelf Speaker Vertical Contourl Audio Measurements.png


Speaker Listening Test
For those of you bothered by these remarks, please skip to the conclusions. Don't want you to suffer needlessly....

I powered the Klipsch RP-600M using my main system (amplification 1000+ watts). I was expecting bad sound but man, this is really, really bad sound. No detail. Muddy bass and somewhat but not extremely bright. I dial in my room mode bass correction and that helps a tiny bit but suffering continues as I go to track after track.

Testing the theory that the crossover dip can be repaired with EQ, I dialed that in using Roon parametric EQ. And while I was at it, I pulled down the extreme highs as well. This is the end result:

Roon Filters.PNG


The yellow filter above fixing the hole was stunning! It transformed the speaker into a completely different device. Back was the detail, and beautiful vocals. Our hearing is the most sensitive in 2 to 5 kHz so you don't want a speaker pull down that area or you lose detail. There was a trade off in making the sound a bit bright if you push the Gain higher. Still, it sounded good up to 5+ dB of boost.

The roll off was mostly good but too crude.

Normally I don't suggest letting automated room EQ fix the speaker but in this case, I would let it beat it into shape.

My quick fixes were good enough for me to sit there and want to enjoy some tracks of music! I pity on people who buy this speaker with no means of EQ.

Conclusions
Out of the box, the Klipsch RP-600M throws out the rule book, thinking that if you just sold boosted lows and highs and leaving mids behind is a good idea. It is not. Objective and subjective testing shows this to be a horrible choice ranking the speaker as one of the worst I have tested. Dial in some simple EQ though and the speaker transforms into a beauty. The "horn" is actually not a horn but a waveguide that is doing its job to provide uniform off-axis response allowing one to EQ the mid-range dip.

Since I have to score the speaker as designed, it gets my worst rating of "stay away." If you have ability to EQ, and you better do if you are hanging around this forum, then you have a good offering.

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

Cabin fever is getting to me despite glorious sunshine outside. Itching to go out but of course cannot. So I am thinking if my bank balance goes up I will be happier. So please donate using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

Cahudson42

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#5
A pigs ear into a silk purse - with EQ. Wow. We really need amir to follow up on his two initial tutorials with REW and AutoEQ.. And reviews of DSP-408 ( I dislike having any PC with miniDSP) and other DSP hardware..

I, for one, really like it when amir sees a blatant deficiency and fixes it as part of the review.
 
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Daverz

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#6
I wonder how much trouble that dip below 4 Ohms would give the typical mass-market receiver.

Inevitably, GR-Research has crossover mods that greatly improve the frequency response:


 
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#10
What's the crossover frequency for this one? 1600 Hz?

Seems like the tweeter starts roll-off well before the crossover frequency. Maybe they need to crossover this low because the woofer is horrible. Can't think of any other good reasons.

The drivers are probably also way out of phase at the normal listening axis. The frequency response might look better if you place the speakers on top of a bookshelf and then lie down on the floor. (fetal position optional)
 

gr-e

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#11
Spinorama_stock.png
Spinorama_filter1.png
Spinorama_filter3.png

The actual result may be different depending on how in-phase the drivers are
 
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MZKM

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#12
What's the crossover frequency for this one? 1600 Hz?

Seems like the tweeter starts roll-off well before the crossover frequency. Maybe they need to crossover this low because the woofer is horrible. Can't think of any other good reasons.

The drivers are probably also way out of phase at the normal listening axis. The frequency response might look better if you place the speakers on top of a bookshelf and then lie down on the floor. (fetal position optional)
Klipsch states 1500Hz.
 

napilopez

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#13
This is a really interesting case. It's pretty remarkable how good the directivity is given how flawed the on-axis is. Those DI curves are better than the vast majority of the speakers tested so far.

This suggests to me decent engineering compromised by 'tuning by ear.' Why you would tune 2K down by a good 5 dB, I have no idea, especially considering this area is already compromised by interaural crosstalk -- and even more so on a narrowish directivity design.

I wonder what Klipsch's active speakers are like.
 
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amirm

amirm

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Thread Starter #14
What's the crossover frequency for this one? 1600 Hz?

Seems like the tweeter starts roll-off well before the crossover frequency.
Here is the stereophile measurements:

 

mhardy6647

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#16
1584664308767.png

That dip is the classic "boom and sizzle" school of loudspeaker design that sold millions of speakers at places like Radio Shack from the late 1960s well into the 1980s. :( The "big sound" as my father would've referred to it (albeit in much larger monkey coffin type loudspeakers).
 

tuga

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#19
View attachment 55072
That dip is the classic "boom and sizzle" school of loudspeaker design that sold millions of speakers at places like Radio Shack from the late 1960s well into the 1980s. :( The "big sound" as my father would've referred to it (albeit in much larger monkey coffin type loudspeakers).
To my ears the boom-tizzz is more curve shaped. This speaker has the middle midrange (250-1000Hz) at the right level.
Most instruments' fundamental frequencies won't go much higher than 2-3k.

The dip in the presence region is preposterously gargantuan, though...
 

wwenze

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#20
At least the vertical directivity is consistent with the horizontal directivity. And we can say at least we won't be afraid of treble reflections. I presume spinorama already takes those into account when generating the in-room frequency response.

At this point I'm convinced the "Klipsch sound" is intentional.
 
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