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Klipsch RP-8000F Tower Speaker Measurements and Analysis

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RP8000 outdoors testing3.jpg

The Klipsch RP-8000F speakers were measured in free-air at a height of 4 feet at a 2-meter distance from the microphone, with the microphone raised to a 7’ elevation that was level with and aimed at the tweeter center. The measurements were gated at 5-milliseconds. In this time window, some resolution is lost below 400 Hz and accuracy is completely lost below 200 Hz. Measurements have been smoothed at a 1/24 octave resolution.

 RP8000 waterfall response 3D.jpg

RP8000 waterfall response 2D.jpg

Klipsch RP-8000F Horizontal Response +/- 100 degrees

The above graphs depict the Klipsch RP-8000F’s direct-axis and horizontal dispersion out to a 90-degree angle in five-degree increments. The first thing to note is how remarkably flat the direct axis response is. For all of Klipsch’s reputation of having sizzling hot treble, it just isn’t here. This is a very neutral response. The region between 1.5 kHz and 4 kHz does have an approximately 2 dB shallowness, and that slightly recessed upper midrange might make the speaker sound slightly bright compared to a totally neutral response, but it wouldn’t be very noticeable otherwise. In fact, in my listening, I wouldn’t have characterized the speaker as ‘bright’, although not ‘warm’ either. It sounded neutral to my ears, and that is basically what is being displayed in these measurements. What’s more is that this midrange recession happens right below the range where most treble tone controls attenuate, so those who want a warmer sound can simply bring down the treble tone control by a few dB. One small blemish that we see in these graphs is there is a null around the crossover point that ends up turning into a fairly high Q dip at far-axis angles. This isn’t really a serious flaw since it is not a very wide bandwidth dip, and it doesn’t subtract much until one is very far off-axis, but I don’t think very many people are going to be listening to these things at angles greater than 50 degrees. It is an imperfection, but it isn’t likely to be very audible.

We do see some interesting diffraction effects occur off-axis at very high frequencies, and these may be coming from the interior of the horn. They are not likely to be audible at all for a variety of reasons. One reason is that they are far too narrow bandwidth to make a serious difference, and another is that, as diffraction effects, they change in frequency at different angles and different distances, so they would not be a persistent tonal effect. They also occur at such high-frequency bands that many people are not very sensitive at that range and wouldn’t be able to discern small ripples of such modest amplitudes. They are an interesting acoustic effect to observe in measurements but are not likely to mar the sound. The bottom line for this set of measurements is that the RP-8000F is showing itself to be a relatively accurate loudspeaker.   

RP8000 polar map.jpg 

Klipsch RP-8000F Polar Map of Horizontal Response +/- 100 degrees 

The above graphs show the same information that the preceding graphs but depict it in a way that can offer new insight regarding these speakers’ behavior. Instead of using individual raised lines to illustrate amplitude, these polar maps use color to portray amplitude, and this allows the use of a purely angle/frequency axis perspective. The advantage of these graphs is they can let us see broader trends of the speaker’s behavior more easily. There is a lot of good news in this polar map of the RP-8000F’s horizontal response. We can see that the hybrid tractrix horn does a pretty good job of controlling dispersion all the way up to nearly 16 kHz. Between 15 to 16 kHz, the tweeter is beaming pretty hard, so it is not really interacting with the horn anymore. That is not a big deal since not many adults can hear well at such high frequencies, but those who don’t want to miss this range should listen within a +/- 15-degree angle of direct axis. The horn keeps dispersion pretty stable within about 35 degrees of direct axis from about 2 kHz and above, with some minor flares near the bottom of its passband. Although there is waistbanding around the crossover frequency of 1,750 Hz, the 8” woofers are otherwise well-matched in directivity to the horn in this region in that they do not make for a dramatic shift in dispersion around the crossover point. An advantage with a relatively narrow dispersion pattern like this is that these speakers will not be as adversely affected if they are placed near a sidewall since there isn’t as much lateral acoustic energy to reflect off of nearby surfaces. The dispersion pattern here isn’t absolutely perfect, but it is pretty good, and the result is that listeners should experience a fairly consistent sound anywhere within a 30-degree angle of direct axis, which is an angle that will cover most listening positions in a normal room.

 RP8000 bass response2.jpg

Klipsch RP-8000F Low-Frequency Groundplane Response 

The above graph shows the Klipsch RP-8000F low-frequency response that I captured using groundplane measurements (where the speaker and microphone are on the ground at a 2-meter distance in a wide open area). In this response, we see a very slight roll-off from 200 Hz to just under 50 Hz, and 40 Hz is clearly the port-tuning frequency. In other speakers of this price class, we have seen a more aggressive roll-off down to port tuning so that the speakers do not risk overloading the low-frequency response of room and so the low end of their +/-3dB spec has largely been with room acoustics factored in. Klipsch seems to subscribe to this strategy but not nearly to the same degree, so their anechoic low-frequency response is less tapered off than other tower speakers in its class. The disadvantage is that a small room or congested area might boost the low-frequencies to an unnaturally bass-heavy sound. Klipsch may be betting that few people are going to place large tower speakers with dual 8” woofers in a small room, which is a sensible bet to make. With this kind of bass response, users may want to keep these speakers away from corners and side walls for the most natural bass sound.

The solid bass response down to 40 Hz means that for most types of music, the addition of a subwoofer is not needed. Room acoustics will likely take that response down a bit lower as well, and few types of music dig lower than the upper 30 Hz range. Pipe organ aficionados and bass-heavy electronic music fans may still want to use subs, since those music types do dip under the tuning frequency of this speaker. This kind of extension will not be able to capture all of the deep bass in many modern action or science fiction movies either. Nonetheless, the RP-8000F is a fairly capable speaker for low frequencies. 

 RP8000 Impedance.jpg

Klipsch RP-8000F Impedance and Phase Response 

The Klipsch RP-8000F is a high-fidelity speaker that faithfully reproduces the sound of the source content.

The above graphs show the electrical behavior of the Klipsch RP-8000F. Klipsch specifies this speaker with a nominal impedance “compatible with 8 ohms” which is a fairly ambiguous spec. I take that to mean you can safely use this speaker on amplifiers that are only rated for 8-ohm loads, and that is largely true. There isn’t much here that would be problematic for most amplifiers. The impedance minima occur at 160 Hz with 5.17 ohms, but the phase angle isn’t too severe. A more challenging point may be the port tuning frequency at 40 Hz which sees a 5.7-ohm impedance dip at a steep phase angle. That may be tough on feeble amplifiers if you crank them hard, but even an amp in a mid-range AVR should be able to handle these speakers without much of an issue. The use of a subwoofer here would make these speakers a much easier electrical load by alleviating the amplifier of having to power the port frequency range.

What helps to make the RP-8000F an easier load than many other speakers is its above average sensitivity. I measured its sensitivity as 92.1 dB for 2.83v at 1 meter. That isn’t bad; it’s better than most speakers in this type and price class. However, it is significantly below what Klipsch specifies for it which is 98 dB for 2.83v at 1 meter. That is quadruple the sensitivity that I measured. Klipsch is using an in-room estimation of sensitivity that factors in a quarter-space environment over a greater distance. It is true that the in-room sensitivity would be increased, but I think that should be stated in their specs if that is their reasoning for their sensitivity rating. We've seen this discrepancy in other Klipsch products so it doesn't seem to be a statistical outlier in how the brand rates sensitivity of their products.

Conclusion

As a speaker brand, Klipsch has faRP8000 pair full flash2.jpgshioned and honed a reputation for themselves that the RP-8000F doesn’t quite live up to- and that’s a good thing, in my opinion. The RP-8000F is better than a mere “rock’n’roll” speaker. It is a high-fidelity speaker that faithfully reproduces the sound of the source content. Users who want a signature ‘rock’n’roll’ response of hot treble and hot midbass may want to use an equalizer with these speakers. These speakers look a lot more aggressive than they sound, thankfully. Without the grilles, they have an almost muscle car look. Historically speaking, muscle cars could go fast in a straight line but didn’t have great handling otherwise. An analog in the loudspeaker world might be something that can get very loud but doesn’t have a very linear frequency response. In both cases, what is missing is control over all of that power. This is not at all the case with the RP-8000F.

Before wrapping this review up, I will enumerate some of the pros and cons of this product, and, as always, I will start with the cons. There are only two, and only one concerns the RP-8000F itself. The first is that the crossover doesn’t quite provide a perfectly seamless transition from woofer to tweeter. It isn’t terrible, and it isn’t even likely to be very audible, so this complaint might be totally academic, but I think that perhaps the crossover could be made so that the woofer/tweeter transition is nearly invisible so that there is no off-axis evidence of it. That might require a much more complex crossover which would raise costs considerably though, so it might be a case of diminishing returns, but it would be a nice touch, even if only for merely theoretical benefits.

RP8000 tweeter close up5.jpg

The other ‘con’ in our pros and cons list concerns its sensitivity spec, which is rather inflated on the face of it. This is not a 98 dB/2.83v/1 meter sensitive speaker, and it’s not even close to that level. But here my beef is with Klipsch’s marketing and not the speaker itself. Its sensitivity is just fine at 92.1 dB for 2.83v at 1 meter, and as I said before, that is above average. The speaker itself is very good, but this reported spec is not accurate by the norms that sensitivity is normally reported. This is a powerful speaker that few owners will ever drive to the maximum limits of their amplifier, so the sensitivity spec doesn’t need to be represented in this misleading manner. If Klipsch wants to emphasize that aspect of the speaker, they just give the true sensitivity spec some context.

Let’s now go over some of the highlights of the RP-8000F. The first, as I have mentioned, is the neutralRP8000 outdoors8.jpg sound. This speaker does not significantly emphasize any particular frequency band and has a tonally balanced character. Furthermore, it has fairly good directivity control with good off-axis uniformity, so non-direct axis sound correlates nicely with direct sound. That means that it will have the same tonal balance in a 60-degree angle across the front of the speaker. It also means that reflected sound will not be dissimilar to direct sound, so a gob of acoustic treatments are not going to be needed to make it sound better. To put it simply, this is a speaker of very good sound quality that sounds good with any content.

Aesthetically these speakers also look good, at least in the gloss black edition that we have in for review. That gloss black is a $300 surcharge for the pair over the standard RP-8000F finish, but that premium sure does make these speakers look slick. The standard edition looks fine and might be a better value if money is tight and the buyer’s highest priority is the sound. Those using these things around a projection screen might want to think twice about the gloss black finish as well, as this kind of finish reflects light back into a projection screen pretty easily.

Their dynamic range is very good, as one would imagine given their design. They can get loud with even modest amplification, my griping about the inflated sensitivity spec notwithstanding. They have punchy and deep bass with a true anechoic response that is solid down to 40 Hz. The RP-8000Fs are not a very taxing electrical load either, and most amplifiers are suitable for driving them.RP8000 logo.jpg

The RP-8000 might look like a muscle car, but it drives like a sports car. It is a well-engineered, well-crafted loudspeaker whose performance doesn’t quite match its aesthetic. It looks like it was made for ear-splitting, loud music, but the fact is it handles all content with finesse and equanimity. Klipsch aimed for accuracy as a performance target and has largely achieved it. I commend Klipsch for that and hope they continue making speakers this good.

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

  • StarStarStarStarStar — Excellent
  • StarStarStarStar — Very Good
  • StarStarStar — Good
  • StarStar — Fair
  • Star — Poor
MetricRating
Build QualityStarStarStarStar
AppearanceStarStarStarStar
Treble ExtensionStarStarStarStarStar
Treble SmoothnessStarStarStarStar
Midrange AccuracyStarStarStarStar
Bass ExtensionStarStarStarStar
Bass AccuracyStarStarStarStarStar
ImagingStarStarStarStarStar
Dynamic RangeStarStarStarStarStar
Fit and FinishStarStarStarStar
PerformanceStarStarStarStarStar
ValueStarStarStarStarStar

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About the author:

James Larson is Audioholics' primary loudspeaker and subwoofer reviewer on account of his deep knowledge of loudspeaker functioning and performance and also his overall enthusiasm toward moving the state of audio science forward.

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Recent Forum Posts:

JengaHit posts on May 17, 2019 02:17
Danzilla31, post: 1316817, member: 85700
Although they are more controlled with the dispersion I have no problem setting up a wide sweet spot in my room with them.
I've been able to set up a ~6-7 ft wide sweet spot with my Hsu CCB-8's using time-intensity trading/extreme toe-in (as they are controlled directivity/narrow dispersion speakers); for movies in a 2.1 set-up like mine this is the best way to accomodate multiple listeners without using a center speaker. I was curious if the RP-8000's could achieve the same effect. Narrow-dispersion speakers are well suited to time-intensity trading. Have my eye on the RP-8000's. Looks like a superb tower-speaker value.
Ybills15 posts on May 16, 2019 22:40
I know this may be a little late but the 8000f models are currently on sale on crutchfield and amazon for 958 a pair! Also there is a package on amazon that will throw in the 504c with two RP 8000f's for 1299 which I took advantage of about a month ago! Absolutely no regrets!
Danzilla31 posts on May 16, 2019 12:06
JengaHit, post: 1316726, member: 88330
As the 8000's are narrow dispersion, has anyone experimented with time-intensity trading (extreme toe-in, axis crossing 1-2 ft in front of listening position) to widen the sweet spot for 2-ch listening with them?
Although they are more controlled with the dispersion I have no problem setting up a wide sweet spot in my room with them.
JengaHit posts on May 16, 2019 00:36
As the 8000's are narrow dispersion, has anyone experimented with time-intensity trading (extreme toe-in, axis crossing 1-2 ft in front of listening position) to widen the sweet spot for 2-ch listening with them?
HowardS posts on April 29, 2019 11:02
bigkrazy155, post: 1313549, member: 88650
I'm trying to figure out if the 8000s would be overkill for my room. It measures 22ft x 11ft x 7.5ft (basement foundation/tile floor, drywall and drop ceiling). It does open into a reasonably sized stairwell (close to 1000 ft cubed) that has a door at the top. Usage will be 90/10 in favor of movies and I'm going to get subs regardless. The primary seating position will be about 10 - 12 ft from the LRC.

I'm pondering the 8000 vs 6000 vs 5000 or the 600m on stands. Any input would be greatly appreciated. Thanks!

I have my 8000Fs in a smaller room than yours as I am waiting on my home to be built. They would not be overkill for your setup, in fact, I wouldn't go with anything smaller.
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