Triggered by the frequent criticism from gr-research of the simple two-way loudspeakers, especially the standard hi-fi floorstanding speakers from Klipsch, I took a pair of old RF15s from the cellar and put them on the measuring table.
That was some time ago now.
After a lot of back and forth, I decided to follow Danny's general recommendations. I designed several concepts of potential crossovers/filters. From the two-way system to the three-way to the two-and-a-half system, everything was included.
Everything was recorded using measurement technology; I use CLIO and both a Dayton and a well-known Bayerdynamic measurement microphone. The entire program was used as methods: ground plane, tripod, various excitations, distances, just the normal madness -> measurements in a low-reflection room/chamber (RAR) would also have been possible.
The HT with its horn differed a lot from the two speakers, let's get this out of the way right away. This difference in SPL was clearly audible later with the new crossovers.
(...)
That was some time ago now.
After a lot of back and forth, I decided to follow Danny's general recommendations. I designed several concepts of potential crossovers/filters. From the two-way system to the three-way to the two-and-a-half system, everything was included.
Everything was recorded using measurement technology; I use CLIO and both a Dayton and a well-known Bayerdynamic measurement microphone. The entire program was used as methods: ground plane, tripod, various excitations, distances, just the normal madness -> measurements in a low-reflection room/chamber (RAR) would also have been possible.
The HT with its horn differed a lot from the two speakers, let's get this out of the way right away. This difference in SPL was clearly audible later with the new crossovers.
(...)
All subsequent designs now largely took this circumstance into account, but I managed to fully compensate for this inherent HT driver problem in the 2+1/2 or 3 way concepts, even if the measurement report and the simulation gave a different impression.
Every new crossover (also completely independent of high-priced component quality) and concept could not convince me. Yes, the last 2+1/2 scenario generated pretty good frequency response records, and the impedance curve was also smoothed later.
However, this technically more perfect overall result was only convincing in the immediate vicinity. At somewhat greater distances, the speaker no longer really reproduced anything, it was no longer able to captivate and create a spatial effect - it even lacked liveliness and punch.
So I put the project on ice again.
(...)
Every new crossover (also completely independent of high-priced component quality) and concept could not convince me. Yes, the last 2+1/2 scenario generated pretty good frequency response records, and the impedance curve was also smoothed later.
However, this technically more perfect overall result was only convincing in the immediate vicinity. At somewhat greater distances, the speaker no longer really reproduced anything, it was no longer able to captivate and create a spatial effect - it even lacked liveliness and punch.
So I put the project on ice again.
(...)
Really disappointed, I decided at some point to fully restore the original concept and filter.
Without any verifying measurements and with slightly different components, the cheapest bipolar electrolytic capacitors and air coils, slightly different capacitance values - for simplicity and availability - I got to work 8 days ago.
For 7 days now, the ancient Klipsch has been playing flawlessly again - just as I would expect from an entry-level Klipsch.
#
Have you had similar experiences?
From this project, I can only advise you not to touch the original filter, the crossover.
kindly,
HBt.
Without any verifying measurements and with slightly different components, the cheapest bipolar electrolytic capacitors and air coils, slightly different capacitance values - for simplicity and availability - I got to work 8 days ago.
For 7 days now, the ancient Klipsch has been playing flawlessly again - just as I would expect from an entry-level Klipsch.
#
Have you had similar experiences?
From this project, I can only advise you not to touch the original filter, the crossover.
kindly,
HBt.
Maybe the TSP of my woofers, determined after more than 15 years of daily use and a break in the basement.
No1
No2
No3
No4
No1
- Piston Diameter = 110 mm
- f(s)= 60.46 Hz
- R(e)= 6.108 Ohms
- Z(max)= 64.28 Ohms
- Q(ms)= 4.617
- Q(es)= 0.4848
- Q(ts)= 0.4388
- V(as)= 11.16 liters (0.3941 cubic feet)
- L(e)= 0.6825 mH
- n(0)= 0.4851 %
- SPL= 88.96 1W/1m
- M(ms)= 7.874 grams
- C(ms)= 0.88 mm/N
- BL= 6.139
- K(r)= 0.335
- X(r)= 0.3468
- K(i)= 0.007056
- X(i)= 0.6986
No2
- Piston Diameter = 110 mm
- f(s)= 59.92 Hz
- R(e)= 6.25 Ohms
- Z(max)= 74.02 Ohms
- Q(ms)= 4.543
- Q(es)= 0.419
- Q(ts)= 0.3836
- V(as)= 11.36 liters (0.4012 cubic feet)
- L(e)= 0.7164 mH
- n(0)= 0.5564 %
- SPL= 89.55 1W/1m
- M(ms)= 7.873 grams
- C(ms)= 0.896 mm/N
- BL= 6.65
- K(r)= 0.3507
- X(r)= 0.3483
- K(i)= 0.008953
- X(i)= 0.6817
No3
- Piston Diameter = 110 mm
- f(s)= 63.83 Hz
- R(e)= 6.124 Ohms
- Z(max)= 66.08 Ohms
- Q(ms)= 4.34
- Q(es)= 0.4432
- Q(ts)= 0.4022
- V(as)= 10.01 liters (0.3537 cubic feet)
- L(e)= 0.7265 mH
- n(0)= 0.5601 %
- SPL= 89.58 1W/1m
- M(ms)= 7.871 grams
- C(ms)= 0.79 mm/N
- BL= 6.604
- K(r)= 0.4816
- X(r)= 0.3193
- K(i)= 0.004103
- X(i)= 0.7493
No4
- Piston Diameter = 110 mm
- f(s)= 59.92 Hz
- R(e)= 6.157 Ohms
- Z(max)= 65.31 Ohms
- Q(ms)= 4.527
- Q(es)= 0.4711
- Q(ts)= 0.4267
- V(as)= 11.36 liters (0.4012 cubic feet)
- L(e)= 0.688 mH
- n(0)= 0.4948 %
- SPL= 89.04 1W/1m
- M(ms)= 7.873 grams
- C(ms)= 0.896 mm/N
- BL= 6.224
- K(r)= 0.3592
- X(r)= 0.3416
- K(i)= 0.009942
- X(i)= 0.6678
Attachments
Difficult to answer, because technically speaking and also confirmed by measurements, the modified speaker was better. At close range and optimally positioned, it was actually perfect, except for the small level difference in the treble range between the two channels. Perhaps it should also be mentioned that in my case the speakers are not positioned with their backs to a wall; their backs face another, open room. The acoustics are not easy to handle, but at some point I figured out the trick (around 1996).
Danny R. is absolutely right, but in the far field and moving freely around the room, a modification simply doesn't fit.
The crossover, which has now been evaluated quickly and not yet by measurement, brings everything back into balance more lively and with a seemingly better fundamental range.
It actually corresponds to the original.
There may also be something fundamentally wrong with the 2+1/2 concept per se, in terms of sound, i.e. a completely subjective assessment.
The short answer is yes.
However, it is important to know that there is no official recommendation/investigation or kit from gr-research for the RF15. Not to my knowledge. However, the fact that Danny often complains about this special construction and the XO is also given here. Basically, due to the system - that's why I wanted to give this basic recommendation for the Klipsch floorstanding speakers a chance.
And in the end I wasn't satisfied enough with them to use them on a daily basis. My personal conclusion is therefore to leave the Klipsch RF15 in its original condition.
However, it is important to know that there is no official recommendation/investigation or kit from gr-research for the RF15. Not to my knowledge. However, the fact that Danny often complains about this special construction and the XO is also given here. Basically, due to the system - that's why I wanted to give this basic recommendation for the Klipsch floorstanding speakers a chance.
And in the end I wasn't satisfied enough with them to use them on a daily basis. My personal conclusion is therefore to leave the Klipsch RF15 in its original condition.
This is a tricky subject, firstly my real name is on the logs and secondly they show the product unadorned. I could of course call up CLIO again and edit the raw data sets so that everything looks much nicer than it actually is.
Basically, the descriptions only confirm what you can already theoretically deduce quite clearly from the structure and geometry of the tweeter horn, at the same time the driver (can you even call it or the interaction with the stem a compression driver? or is it more a kind of waveguide?) ...
The woofers are fine, absolutely - but the HT driver might be better for spoiled hi-fi eyes. I suspect that this is also due to a large dispersion in production. You also have to bear in mind that the RF15 was a very inexpensive product.
Basically, my measurements coincide with those that gr-research has repeatedly criticized in the past.
But one thing you always have to keep in mind is that the Klipsch engineers know why they implemented their solution.
In any case, this old entry-level speaker is 100% suitable for getting the listener positively enthusiastic about the P. Klipsch myth. Once infected, you can't get away from it.
Dear dkfan9,
please let me think about it for a few days - the material is extensive. You can also send me a PM as a reminder. First of all, I state that it makes no real sense to change the system to 2+1/2 or even 3 way.
Perhaps a short, inspiring excursion to the (edited) statements on system theory by Dr. Roland Gauder (Isophon now Gauder Akustik) is worthwhile. Even if he talks a lot. He gets to the heart of the matter, namely that we are not arbitrarily free in our choice of network and the resulting crossover frequency.
And this is exactly what you can immediately recognize from the unvarnished measurement records, and even more so.
#
And regardless of that, I'm somehow in love with my low-cost-product and Klipsch.
regards,
HBt.
Basically, the descriptions only confirm what you can already theoretically deduce quite clearly from the structure and geometry of the tweeter horn, at the same time the driver (can you even call it or the interaction with the stem a compression driver? or is it more a kind of waveguide?) ...
The woofers are fine, absolutely - but the HT driver might be better for spoiled hi-fi eyes. I suspect that this is also due to a large dispersion in production. You also have to bear in mind that the RF15 was a very inexpensive product.
Basically, my measurements coincide with those that gr-research has repeatedly criticized in the past.
But one thing you always have to keep in mind is that the Klipsch engineers know why they implemented their solution.
In any case, this old entry-level speaker is 100% suitable for getting the listener positively enthusiastic about the P. Klipsch myth. Once infected, you can't get away from it.
Dear dkfan9,
please let me think about it for a few days - the material is extensive. You can also send me a PM as a reminder. First of all, I state that it makes no real sense to change the system to 2+1/2 or even 3 way.
Perhaps a short, inspiring excursion to the (edited) statements on system theory by Dr. Roland Gauder (Isophon now Gauder Akustik) is worthwhile. Even if he talks a lot. He gets to the heart of the matter, namely that we are not arbitrarily free in our choice of network and the resulting crossover frequency.
And this is exactly what you can immediately recognize from the unvarnished measurement records, and even more so.
#
And regardless of that, I'm somehow in love with my low-cost-product and Klipsch.
regards,
HBt.
Exactly!
Not only the excitation signal plays a major role, but also terz-weighted noise (and RTA) ... in space, at different coordinates ... and the many interactions ...
Acoustics is a field all of its own, which I only ever touch on in passing. Semi-professional is already too ambitious to classify myself there. But it is also a field of control engineering and communications engineering
.
Maybe it would be good to start your own thread regarding this floorstanding speaker. All geometric data; areas, volumes, positions, the horn, the port ... and a few electrical ones are also very important.