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JBL HDI-4500 Center Channel Speaker Review

hardisj

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Full written review is on my site here:
https://www.erinsaudiocorner.com/loudspeakers/jbl_hdi-4500/



JBL HDI-4500 Center Channel Speaker Review
  • Thursday, Apr 1, 2021



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Foreword
The review on this website is a brief overview and summary of the objective performance of this speaker. It is not intended to be a deep dive. Moreso, this is information for those who prefer “just the facts” and prefer to have the data without the filler.


I reviewed the big brother JBL HDI-3800 floorstanding speakers here if you are interested in those as well.



Information and Photos

Note: JBL was kind enough to loan me this item for test. I was not paid for my review and was not told what to say.
The JBL HDI-4500 is 2.5-way center channel speaker. The below is from the manufacturer’s website:
Designed and engineered in JBL’s world-famous acoustic engineering facility in Northridge, California, the HDI-4500 is the anchor of a complete HDI Series surround system. This center channel loudspeaker features a 2 ½-way design with patented High-Definition Imaging (HDI™) waveguide technology, the patented 2410H-2 1-inch (25mm) compression driver, and quadruple 5.25-inch (130mm) Advanced Aluminum Matrix cone woofers for powerful dynamics and incredibly accurate sound reproduction. The HDI-4500 enclosure is heavily braced to provide a solid acoustic foundation, and incorporates a bass reflex design with dual rear-firing, computer-optimized flared ports. The sophisticated curved cabinet features a modern design finished in a choice of automotive-grade painted High Gloss Black, or furniture-grade satin Walnut or Gray Oak wood veneers. A black cloth, magnetically attached grille completes the elegant appearance.​

MSRP for the single speaker is approximately $1750 USD.

And here are some specs, again from the manufacturer’s website:


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CTA-2034 (SPINORAMA) and Accompanying Data

All data collected using Klippel’s Near-Field Scanner. The Near-Field-Scanner 3D (NFS) offers a fully automated acoustic measurement of direct sound radiated from the source under test. The radiated sound is determined in any desired distance and angle in the 3D space outside the scanning surface. Directivity, sound power, SPL response and many more key figures are obtained for any kind of loudspeaker and audio system in near field applications (e.g. studio monitors, mobile devices) as well as far field applications (e.g. professional audio systems). Utilizing a minimum of measurement points, a comprehensive data set is generated containing the loudspeaker’s high resolution, free field sound radiation in the near and far field. For a detailed explanation of how the NFS works and the science behind it, please watch the below discussion with designer Christian Bellmann:

A picture of the setup in my garage:
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The reference plane in this test is at the tweeter. T
he speaker was tested in ported configuration (the port was not sealed).
All testing in this review was done without grille.
The speaker was tested in the horizontal configuration (as it is expected this is how it will be used in the real world).


Measurements are provided in a format in accordance with the Standard Method of Measurement for In-Home Loudspeakers (ANSI/CTA-2034-A R-2020). For more information, please see this link.

CTA-2034 / SPINORAMA:
JBL%20HDI-4500%20--%20CEA2034.png


Early Reflections Breakout:
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Estimated In-Room Response:
Estimated%20In-Room%20Response.png


Horizontal Frequency Response (0° to ±90°):
SPL%20Horizontal.png


Vertical Frequency Response (0° to ±40°):
SPL%20Vertical.png


Horizontal Contour Plot (not normalized):
JBL%20HDI-4500_Horizontal_Spectrogram_Full.png


Horizontal Contour Plot (normalized):
JBL%20HDI-4500%20Beamwidth_Horizontal.png


Vertical Contour Plot (not normalized):
JBL%20HDI-4500_Vertical_Spectrogram_Full.png


Vertical Contour Plot (normalized):
JBL%20HDI-4500%20Beamwidth_Vertical.png




Additional Measurements

Impedance Magnitude and Phase + Equivalent Peak Dissipation Resistance (EPDR)

For those who do not know what EPDR is (ahem, me until 2020), Keith Howard came up with this metric which he defined in a 2007 article for Stereophile as:
… simply the resistive load that would give rise to the same peak device dissipation as the speaker itself.
A note from Dr. Jack Oclee-Brown of Kef (who supplied the formula for calculating EPDR):
Just a note of caution that the EPDR derivation is based on a class-B output stage so it’s valid for typical class-AB amps but certainly not for class-A and probably has only marginal relevance for class-D amps (would love to hear from a class-D expert on this topic).
JBL%20HDI-4500_Impedance_0.1v.png





Harmonic Distortion
Harmonic Distortion at 89dB @ 1m:
JBL%20HDI-4500%20--%20Harmonic%20Distortion%20%2889dB%20%40%201m%29.png


Harmonic Distortion at 97dB @ 1m:
JBL%20HDI-4500%20--%20Harmonic%20Distortion%20%2897dB%20%40%201m%29.png





“Globe” Plots
Horizontal Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
JBL%20HDI-4500_360_Horizontal_Polar.png







Vertical Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
JBL%20HDI-4500_360_Vertical_Polar.png







Parting / Random Thoughts
Generally speaking, it is ideal to use three of the same speakers when building an L/C/R setup and to also keep the same orientation (i.e., all standing). The reason for this is to keep the same speaker quality between the entire front speakers so as dialogue/effects traverses one side to the other of the soundstage the sound “footprint” (if you will) remains the same. This is logical. However, this is typically not feasible unless you are using an acoustically transparent screen with a projection setup. The overwhelming majority of home theater enthusiasts do not have this luxury and instead opt to use a conventional center channel such as the one I have tested here. The issue with these kind of speakers is they are - essentially - floorstanding speakers, laid on their side. This orientation drastically changes the sound you hear at the listening position. Why does this happen? Well, as you can imagine, a single sound source such as a single woofer would have no effect as you turn it on its side because nothing about the radiation pattern changes; it is still that single woofer no matter how you turn it. A single woofer will not produce the full frequency range as well as a multi-way system (midwoofer+tweeter, midwoofer+midrange+tweeter, etc.). But a multi-way has issues of its own. As you incorporate more drive units into a speaker, the more susceptible a poor design is to poor sound. Those drive units have to go somewhere and you have to design a crossover network for them that allows the speaker to project sound in a radiation pattern that isn’t plagued with mismatches in directivity. Making a good horizontally-oriented center channel is tough. Especially for higher output capability. In order to manage these two you need multiple drive units with good horizontal and vertical directivity. The latter isn’t too hard. The former is. I say all of that to say this: when evaluating a horizontal center channel you know you are already starting with a disadvantage compared to a typical bookshelf or floorstanding speaker. As I said, if one is able, they should orient the center channel vertically (unless, in the rare case, the speaker is designed solely to be oriented horizontally).

Now, with that critical caveat laid out, allow me to highlight some things I think will be useful to those who are considering or plan to purchase the HDI-4500:
  • The on-axis response averages approximately 89dB @ 2.83v/1m.
  • Linearity is pretty good here with a mild trough in the midrange relative to the 1kHz response. In terms of how this will sound, you can expect a mildly “hollow” midrange quality.
  • The high-frequency linearity varies significantly above 9kHz. I believe these are diffraction effects of the waveguide with the proximity of the compression driver to the waveguide throat. How audible are these? Well, that’s a tough one to answer for me, at least. There is a 4dB dip at 10kHz in every angle. The narrow-Q shape and the fact that it is a dip lead me to believe it’s not much of an issue. From there the response picks up and peaks around 15kHz before peaking again at 20kHz+. I can’t provide a real assessment on this because I didn’t come across music that highlighted this, at least in a meaningful or noticeable way. Ideally the response would be more linear here.
  • The low-frequency extension on this speaker is reasonable, in my opinion, for its size. In my listening tests I found it to pack a lot of “punch” but it didn’t dig very low and a good subwoofer crossed somewhere above the 60-80Hz region is my recommendation.
  • You can see directivity changes at the stated crossover points of 600Hz and 2200Hz. Midbass-to-midrange and midrange-to-tweeter, respectively. The latter didn’t seem to be as much of a problem as the former which I get in to in the next bullet point.
  • With respect to seating position, it is apparent that sitting more than ±20° to the side of this speaker results in a very recessed midrange quality. The data shows this, notably in the horizontal globe plot by the orange/yellow area in the 300-800Hz region. (The other sets of horizontal SPL data show this, too.) Listening to the speaker is no different in this regard. There is a *noticeable* loss in speech intelligibility when sitting to the sides of the speaker at an angle greater than 20°. However, if you do some napkin-math you can find that this limit is well-within most seating setups. For example, if you are 8 feet from the speaker to the main listening position then using a maximum angle of 20° off-axis of the center channel means that your buddy/spouse/kid/dog can sit about 3 feet to the side of you. That's reasonable. At 12 feet from the center channel, the person next to you can sit a little over 4 feet from you. That is feasible for most as well. While the ±20° horizontal angle is my maximum off-axis recommendation, there is a loss in output in the 1-2kHz region at this angle. The ±10° region provides a more uniform sound pattern but it is unlikely that this is achievable in most modern seating situations unless there is no listener directly on-axis. Bottom line? Stay within ±20° of the tweeter axis to the sides and you'll be OK. Go beyond that and dialogue will suffer for off-axis listeners.
  • Now, let’s look at the vertical response window. The vertical response window looks good between ±40-50° so while you would want to aim the speaker at the listening position, you have a bit more flexibility in positioning here. In other words, if you have to place the center channel below your TV in your living room, you’ll be OK as long as you tilt the speaker up and aim it toward your listening position. You have much more leeway here than you do in the horizontal axis.
  • The impedance is stated at 4 ohm nominal. The impedance plot shows this to be quite true. I drove this with a Parasound 200 Integrated Amplifier with no issue (rated for 110w @ 4/8 ohm).
  • Output levels. I drove this speaker hard for both music and movies and was able to achieve quite high output. Approximately 100dB at 12 feet with no mechanical issues (port noise, speakers bottoming out, etc.). Distortion on this speaker is also quite low.


Support / Contribute
If you like what you see here and want to help me keep it going, please consider donating via the PayPal Contribute button located on my site. Donations help me pay for new items to test, hardware, miscellaneous items and costs of the site’s server space and bandwidth. All of which I otherwise pay out of pocket. So, if you can help chip in a few bucks, know that it is very much appreciated.

You can also join my Facebook and YouTube pages if you would like to follow along with updates.
 
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Ground-Plane measurement vs NFS

Because there has been concern over the accuracy of the NFS with large/complex speakers in the low-frequency region I have provided evidence that the NFS measurements provided for this speaker are accurate in the LF.

Below you see the on-axis CTA-2034 response in black overlaid on top of the ground-plane measurement in teal. Nearly perfect match below 200Hz*. And, ironically, the HDI-4500 is the one that has been the most troublesome with fitting in the LF. I have literally measured that speaker 6 times to dial in the LF accuracy. Go figure, right?



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*Keep in mind the GP and NFS measurements are expected to be different above a few hundred Hz because I didn't tilt the speaker down to be aimed directly at the mic for the GP test. The GP measurement was only for the low frequency.
 
So that spike up near 20k seems to be consistent among this whole line. Audible? Probably not, but certainly not the prettiest thing I've ever seen.

Anyway, thanks for this review Erin - Always interesting to see.
 
Looks solid for a 2.5-way (doesn’t look worse than any 3-way measured in regards to horizontal off-axis.

As Dennis Murphy suggested in another post, turn this speaker vertical and it‘s Spinorama would be much better but he suggests you won’t really hear a difference (so him saying don’t worry too much about the poor horizontal off-axis of a transitional MTM center).
 
Hope you get to review the KEF RC2 one day Erin. Given the off (vertical) axis placement realities of horizontal centers, I think the concentric design would prove to be of substantial benefit, especially if it performs in line with the R3.
 
Looks solid for a 2.5-way (doesn’t look worse than any 3-way measured in regards to horizontal off-axis.

As Dennis Murphy suggested in another post, turn this speaker vertical and it‘s Spinorama would be much better but he suggests you won’t really hear a difference (so him saying don’t worry too much about the poor horizontal off-axis of a transitional MTM center).

If I may speak for Dennis, I think he would emphasize that there isn't that great of difference between the horizontally placed and the vertically placed speaker when listening on axis. At least that's the conclusion I came to when I did my little test of comparing a horizontal MTM with the same speaker placed vertical.

The poor horizontal dispersion of a horizontal MTM can be an issue for listeners well off-axis, because the sound they hear isn't nearly the same as the sound heard by an on-axis listener.
 
I haver not read through yet. The pics are gorgeous.
 
turn this speaker vertical and it‘s Spinorama would be much better

I have the data for a direct comparison between horizontal and vertical orientation. This isn't the same as I posted in my review and you'll have to ignore the response below 40Hz. This wasn't the "final" dataset but it's enough to compare between the two.

As expected, the difference lies in the listening window, slightly in the early reflections and also the DI results (since they are based on the LW).


Here you go...

Horizontal orientation (as intended to be used):
JBL HDI-4500 -- CEA2034  Sideways.png






Vertical orientation:

JBL HDI-4500 -- CEA2034  Standing Upright.png
 
Hope you get to review the KEF RC2 one day Erin. Given the off (vertical) axis placement realities of horizontal centers, I think the concentric design would prove to be of substantial benefit, especially if it performs in line with the R3.

That's a good point. Maybe at some point I can reach out to them and see if they would be willing to loan me one of their center channel speakers to review.

I'm hoping maybe I'll get a crack at the Blade one day. :D:D:D (May not be able to put it on the NFS, I just want to listen to them)
 
This center design always struck me as the odd box out in the line, because of the obviously compromised driver placement. The measurements IMO confirm that.
 
Horizontal dispersion looks horrible. Is is this bad with other 2 way center speakers?
 
Horizontal dispersion looks horrible. Is is this bad with other 2 way center speakers?
Actually it is a 2.5 way with relatively low crossover frequency, most common 2-way MTMs are even worse there...
 
Horizontal dispersion looks horrible. Is is this bad with other 2 way center speakers?
Look at the RC263 and Sierra Horizon reviews, the horizontal performance is similar.

Then look at the CBM-340 review, the horizontal performance is terrible, I think the red in the polar plot was like +/-10° at the worst.
 
Someone made a comment on my YT page about why we still see toppled MTM designs for center channel speakers. And, while I agree they are far from ideal, I just don't know what the options are for a regular Joe/Jane who doesn't have the luxury of mounting a large center channel under their living room TV or vertically orienting a speaker behind an acoustically transparent screen.

Coaxial/concentric designs will still have issues with SPL (and modulation of HF) if you don't flank them with woofers.
Smaller CTC means smaller drivers which means lower SPL.
Center channels with a vertically oriented M/T but woofers to the side are quite large by comparison and won't likely fit the decor of the room. And they look gaudy (in my humble opinion).

As @Haint mentioned above, it would be interesting to see one of Kef's offerings in the center channel realm. If anyone is apt to pull off a better design that allows less-critical listening angles then I would say it is them thanks to their uni-Q concentric speaker. It would still have to be an MTM but if they can keep the CTC around 13.5-inches (half-wavelength at 500Hz to keep lobing minimal) and with a steep enough slope, they could pull it off.
 
Hope you get to review the KEF RC2 one day Erin. Given the off (vertical) axis placement realities of horizontal centers, I think the concentric design would prove to be of substantial benefit, especially if it performs in line with the R3.
I have Kef R200C in my home cinema replacing the JBL Studio 235C and although is not as sensitive the sound is smoother and better balanced on and off axis
 
Someone made a comment on my YT page about why we still see toppled MTM designs for center channel speakers. And, while I agree they are far from ideal, I just don't know what the options are for a regular Joe/Jane who doesn't have the luxury of mounting a large center channel under their living room TV or vertically orienting a speaker behind an acoustically transparent screen.

Another option is to use 3 identical horizontally oriented channels. Either use 3 center channels that measure well (like the 3 way revels), or active monitors like the KH 310.

They have an excellent CTA 2034, are sealed, have tons of mounting hardware, and can even be flush or recessed mounted in a wall. It works for me!

3C01E13B-3260-460C-A09B-54C48E108858.jpeg


9BC1CBB7-CB96-466A-8F86-6EC55F37DB3B.jpeg
 
Someone made a comment on my YT page about why we still see toppled MTM designs for center channel speakers. And, while I agree they are far from ideal, I just don't know what the options are for a regular Joe/Jane who doesn't have the luxury of mounting a large center channel under their living room TV or vertically orienting a speaker behind an acoustically transparent screen.
I do wonder why you don't see something like this more often, which looks like a decent compromise (Focal Twin 6 Be... I think Infinity used to have have similar ones at one point):
1617381180089.jpeg


 
it would be interesting to see one of Kef's offerings in the center channel realm. If anyone is apt to pull off a better design that allows less-critical listening angles then I would say it is them thanks to their uni-Q concentric speaker. It would still have to be an MTM but if they can keep the CTC around 13.5-inches (half-wavelength at 500Hz to keep lobing minimal) and with a steep enough slope, they could pull it off.

Kef R3/R2C have the woofer crossover at 400hz, which should be low enough that the woofer location/count don't really matter very much for dispersion.

Add to that that the Kef have somewhat narrower dispersion, and don't seem to have any trouble playing loud(at least in the 3-way versions), plus there are floorstanders available and even in-ceiling speakers using the Uni-Q, and I do think they ought to be one of the top picks for HT, at least if you can't afford Genelec Ones ;)
 
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