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Klipsch R-41M Bookshelf Speaker Review

bigx5murf

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Most of the Klipsch I've heard have been on the hot side. Except for my KG4, which sound pretty balanced. Funny so many Klipsch fans treat the KG series as the red headed step child, and praise the high end of other models. Then go and recommend Crites titanium diaphragm upgrades, which for sure will heat up the high end some more.
 

QMuse

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The green circle I've drawn is the tweeter's step. The blue circle could be some very odd tweeter behaviour, but it's extremely likely it's the beginning of the woofer's step (which of course peaks after the tweeter's step, but which IMO almost certainly begins 0.2ms before it):

View attachment 50892

That will be the last I labour this point ;)


Hi guys! Long time reader but I thought time has come to write my first post to try to clear the confusion about this. :)

Actually, there is nothing dramatic and strange happening with Klipsch's step response. In fact, apart from response being inverted, as both drivers are connected with negative acoustic polarity, this step response is actually very typical for a 2-way speaker.

Step response topic has been very well explained by Joe D'Appolito in this article so let's take a look at what he wrote and the graphs he presented.
This is how typical step response of a 2-way speaker looks:

Pic1.JPG


Yep, that's the same one as the one measured with Klipsch, except this one has not been inverted. This graph actually consists of a sum of 2 step responses, tweeter and midwoofer. Luckilly, I can borrow that graph as well from D'Appolitos article:


Pic2.JPG


And the mistery is solved! :)
Let me also do some very basic and ugly drawing just to point out midwoofer is legging behind tweeter app. 0.38 ms, which is also quite typical value for a 2 way systems. If the tweeter wouldn't be sitting in a deep waveguide the difference would be slightly larger but that small difference in timing would anyhow have no impact on perceived SQ. There is also nothing on this graph suggesting poor crossover integration - the "kink" in step response is coming from summation of the tweeter's part that is still oscillating with the smooth part of the midwoofer response.


Klipsch R-41M.png
 
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andreasmaaan

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Sure, I was talking about low pass filters making the woofer slope more gradual. Also, I'm not sure, but higher order filters add some kind of delay to the step response, right?

All minimum phase filters (both low- and high-pass) add delay.* And yes, the magnitude of the delay is linearly proportional to the slope of the filter, so the greater the slope of the filter, the greater the delay. For example, a 24dB/octave filter introcudes twice the delay of a 12dB/octave filter.

FWIW, there's also an inverse linear relationship between the frequency of the filter and the magnitude of the delay. So if you halve the filter frequency, you double the delay.

To give an example to illustrate these relationships, a 12dB/octave high-pass filter at 2000Hz introduces the same delay as a 24dB/octave filter at 4000Hz (but each delay is obviously centred around a different frequency).

*Having said that, certain minimum phase filters sum to a constant (flat) group delay when the high-pass and low-pass sections are time-aligned.
 

KSTR

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How did you determine that the first dip is the woofer and not a tweeter in opposite polarity? Based on the fact that the tweeter is in a deep waveguide? Now that you mentioned the waveguide, your and @andreasmaaan 's suggestion makes more sense than mine. I was originally thinking of something like this
View attachment 50898
Yep, the waveguide is the key, we can see the tweeter's diaphragm is a few cm behind the deepest point of woofer cone. The delay is about 110us which corresponds to 3.8cm which looks just about right.
For the question why the first falling slope is not the initial tweeter step, this is because the next rising edge is much larger which is not a typical highpass response, also note that it would sit on top of the falling initial woofer slope which means the edge height is displayed less than we would see without woofer which makes it even more unlikely that the assumption of inverted tweeter is correct. The only way to really know is looking at the individual step responses, not the sum.

Step responses are not so easy to read, in practice one cannot make any valid interpretation unless much more details about the speaker are given, like in this case: 2-way speaker with set back tweeter.
 

Soniclife

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Ok, I ordered one. What the heck I am going to do with these speakers...I have no idea....
You should probably start a thread asking for help, hopefully someone local to you is able to help, or is there a local shop you could cut a deal with?
 

Francis Vaughan

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Hmmm. So these things have a rear port, and a wall mounting keyhole on the back. What excellent thinking.

One notes that the spec sheet only says that the speakers are "8 ohm compatible". Which is about as weasely as it gets.

I'm curious as to whether the drivers are actually screwed in place, or whether the nice copper coloured cap heads are just moulded into the plastic.
 

anmpr1

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Klipschorns and La Scalas are ancient designs kept around as novelties. Their charm isn't fidelity, it's being ancient.
.
I don't think that's the case at all. Some foks who own them might do it for the nostalgia. Others hear them and say they sound unboxy and lifelike, more so than the typical box speaker. In one of the JBL threads the 'voiced or formatted sound' was discussed and I commented:

In a reference to some of Floyd Toole's work [Sound Reproduction – The Acoustics and Psychoacoustics of Loudspeakers and Rooms] and the JBL 4310 and L100, Toole writes how they exhibited “...a collection of strong resonances that were audible, but seemingly ignored or admired by many.”

There was no 'seeming' about it, and definitely there was no big 'secret' needing to be unearthed. They sold because a vast number of consumers just plain didn't like the [typical box speaker], which was closed in, dull, and essentially lifeless. Not only that, but required a lot of power to come alive, if you could even get it there.

This still holds. It's a sense of immediacy and effortlessness that you don't often get with a lot of box speakers. Electrostatics come close but are a different breed altogether. That said, I don't know about these little speakers. But for $200.00 my guess is that they provide what home theater apartment dwellers on a budget are happy with. Especially with three more and a sub. That's their point. To hold them up to this sort of critical analysis seems to miss it. In any case the measurements should come as no surprise to anyone.

Although it is not the current model, Richard Heyser took one of the large ones apart here:

http://www.soundhifi.com/klipsch/86horn.htm
 

gr-e

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Yep, the waveguide is the key, we can see the tweeter's diaphragm is a few cm behind the deepest point of woofer cone. The delay is about 110us which corresponds to 3.8cm which looks just about right.
Still leaves me wondering why the RP-600m with similar driver offset behaves differently
1582203694777.png
 

Juhazi

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gr-e - look what happens right after 4ms, there's the hickup. Just different x-axis scale and most likely measured at longer distance.

anmpr1 - Americans must remember, that Klipsch, Lansing and JBL horns, panels and other large speakers have never been popular abroad. Japanese have a strange cult of refurbished vintage gear and that's it. We Europeans have our own strange favourites eg. BBC monitors, Quad ESL, Gradients ets.
 
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gr-e

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It's larger woofer has an acoustic centre that is deeper, and therefore further from the microphone, than the 4" woofer in the R-41m.
But the RP-600m has a deeper waveguide
gr-e - look what happens right aften 4ms, there's the hickup. Just different x-axis scale and most likely measured at longer distance.
I'm only looking at which driver arrives first rn

Wish we could see separate driver measurements, too bad this one doesn't have dual binding posts
 

anmpr1

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Yardsale, fleamarket, or donate to charity sales. :)
Or an ASR essay contest: "Why I dislike these speakers more than any other speaker on the market!" The winner gets the pair, from here on out able to live in eternal sonic agony! :cool:
 

andreasmaaan

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But the RP-600m has a deeper waveguide

Good point :)

It's certainly wider, I'm not sure it's necessarily deeper, but you'd expect it to be.

Anyway, I just looked at Stereophile's measurements. The RP-600m uses an entirely different crossover topolgy, with both drivers connected in-phase and with a 4th order acoustic slope (it seems).

I'm not sure it's possible to know for sure without seeing the individual step responses in this case.

It's possible the added depth of the larger woofer is greater than the added depth of the larger tweeter, it's possible that the crossover slopes are not perfectly aligned, or it's possible that the wiggle in the step response that JA identified as a misalignment is in fact a resonance in the output of one of the drive units or the port. Or a combination of the above.
 

Frank Dernie

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Presumably all the treble resonances are due to the horn/waveguide?
Every speaker of this type I have seen measured has them.
 

QMuse

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Still leaves me wondering why the RP-600m with similar driver offset behaves differently
View attachment 50944

It actually doesn't. :)

Main difference is in this case is that both drivers are coonected with positive acoustic polarity so once you invert R-41M step response they would become similar. Time difference between peaks of responses of tweeter and midwoofer is also similar with this graph, app 0.38 ms.

1582203694777.png


What you shouldn't compare is height and depth of those spikes as those are very much related to the # of cycles/octaves of frequency dependent windowing applied when generating graph like this. Same thing applies to comparison of any time-domain graphs (phase, GD, etc) - they all very much depend on applied FDW which makes comparison betweeen graphs very hard as their y-axis values are very much dependent on FDW.
 

KSTR

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Still leaves me wondering why the RP-600m with similar driver offset behaves differently
View attachment 50944
Their conclusion "the tweeter's step has begun to decay..." is plain wrong, for the reasons mentioned. The assumption that the speaker's main lobe is tilted downward is most probaly invalid. One simply cannot infer such info from a step reponse, you either need to have vertical polars or individual mag/phase responses of the drivers.

The 600 has higher crossover frequency and, more importantly, a supposedly much better designed crossover with steeper slopes. Crossover parts are a big factor for BOM cost, that's why on the very cheap lines designers try to get away with the lowest part count and the cheapest stuff.

A quick sim with for the 600 (assumed flat to +-0.2dB) with 1.5kHz XO and 5th order (acoustically, as always) on the woofer (ported @50Hz) and 4th order on the tweeter (set back by 100us), both drivers in phase, gives the following step response which is not that far off.
In that sim I actually have some 60° phase offset at XO (not a good idea, but used for the sake of demonstration), the tweeter lagging, which makes the main lobe tilt upwards, not downwards, which illustrates the above point.
1582207252371.png

If you look hard, the initial rise of the woofer can still be identified
 
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