KEF R3 Speaker Review

[fieldcar]

Two 8" (each) in a sub enclosure which double serves as a stand? Did you do the math assuming the same width and depth as the R3 has?

Gotcha. I didn't see any mention of a very small enclosure.

I'm not a DIY wizard like some on here, but I know enough to be dangerous.
I just plugged in a decent 8" sub like the JL audio 8W3. Here are a few quick sims making a lot of assumptions.

The only way to fix the likely anemic enclosure is playing with EQ. With a ported/vented design, cubic volume makes a Helmholtz resonator... resonate. If it's sealed, EQ is really the only option.

Try something like below, and do not have the bass overlap without a ~80Hz linkwitz-riley crossover between the R3 and the subs. Otherwise, the overlap may be a cancellation nightmare. If they are actually speaker stands, you can cross them over much higher, like up to 120Hz without any directivity issues.

Your max SPL of the subs from 25-80Hz should be about 30dB higher than the R3's with less distortion.

Light grey = ported 1cuft
Dark Grey = sealed 1cuft
Red = ported 5cuft
Green = sealed 1cuft with EQ

 

[muad]

Right, good valid input. I'll do my very best!

Thanks!!

This interests me greatly. I was about to build a subwoofer stand (1x12") for my ls50 metas... But my toddlers are wilder than I anticipated and I can't have a speaker without a grill around (they won't poke it but sometimes he throws stuff before I can stop him and correct him).

So I was thinking of pivoting to using a sub stand with the R3 metas.

Is it possible the sub needs to be decoupled from the mains? As a backup I was thinking of building a wide tv unit that sits over and partially hides the subs, and place the mains on the TV unit. I figure this would help decouple them ala linkwitz.

 

[gegegege]

I have a question that is not closely related to the sound, my R3s are store demo units, they didn't give me any accessories other than the foam for bass adjustment, I searched online and seems I am missing the magnetic grills and rubber feet? Is it a big deal? Would they affect my listening experience in any way?
I am still in the return window. Thanks!

 

[Talisman]

I have a question that is not closely related to the sound, my R3s are store demo units, they didn't give me any accessories other than the foam for bass adjustment, I searched online and seems I am missing the magnetic grills and rubber feet? Is it a big deal? Would they affect my listening experience in any way?
I am still in the return window. Thanks!

If you were going to be using bare speakers then you don't care about the grilles (other than resale value) for the rubber feet, you can use any equivalent rubber feet
Enjoy your R3

 

[fineMen]

Thanks!!

This interests me greatly. I was about to build a subwoofer stand (1x12") for my ls50 metas...

Guys, I'm still talking about the R3s. The subs of mine are special, 18l of internal volume for two 8" closed box. As the measurements show, they cannot compete with the excellent bass reflex alignment of the R3s. To put it in a more catchy way, the R3's single top bass driver in an optimized ported design superseeds quadrupled mediocre driver material used in the same volume as a trivial sealed box.

A top 12" driver in ported 65l of volume clearly yields huge benefits. I tried that. But that's not what I woud define as a stand for the R3.

 

[muad]

Guys, I'm still talking about the R3s. The subs of mine are special, 18l of internal volume for two 8" closed box. As the measurements show, they cannot compete with the excellent bass reflex alignment of the R3s. To put it in a more catchy way, the R3's single top bass driver in an optimized ported design superseeds quadrupled mediocre driver material used in the same volume as a trivial sealed box.

A top 12" driver in ported 65l of volume clearly yields huge benefits. I tried that. But that's not what I woud define as a stand for the R3.

You didnt read my whole thing. I am talking about the R3 as well, in an R3 thread. So is thewas.

Im using a high quality side mounted 12, sealed with dsp boost (have to have dsp if you're going sealed), crossed around 100hz. The overall width will only be slightly wider than the R3s, and 22 inches tall. This design will destroy anything the 6" ported woofer in R3 can do, and with much lower distortion, but will require more power.

 

[fineMen]

You didnt read my whole thing. ...The overall width will only be slightly wider than the R3s, and 22 inches tall. This design will destroy anything ...

let's hope for the best! So, my measurements are no longer needed, thank you for giving note. This is Amir's (watch the spl as 105dB@1m):

 

[thewas]

So, my measurements are no longer needed

Still would be interesting to see them in direct comparison with your dual 8" sub. Also which driver did you use for your sub?

 

[fineMen]

Still would be interesting to see them in direct comparison with your dual 8" sub. Also which driver did you use for your sub?

The R3s are excellent (not only) in respect to bass alignment, period. It will be the hardest challenge to superseed its performance in a volume that is kind of determined by using the sub as a visually appealing stand for an R3. That is what I wanted to convey.

I don't have Klippel (the first Klippel on drivers, not spinorama Klippel) data for the drivers used in my particuar unsuccessful trial. The drivers are typical China made ones with bigger nominal excursion of +/- 8mm, but presumably without precautions regarding field modulation etc

 

[thewas]

The R3s are excellent (not only) in respect to bass alignment, period. It will be the hardest challenge to superseed its performance in a volume that is kind of determined by using the sub as a visually appealing stand for an R3. That is what I wanted to convey.

I don't have Klippel (the first Klippel on drivers, not spinorama Klippel) data for the drivers used in my particuar unsuccessful trial. The drivers are typical China made ones with bigger nominal excursion of +/- 8mm, but presumably without precautions regarding field modulation etc

Using no-name drivers and non ported enclose doesn't allow to generalised that a sub with the same base dimensions of a R3 cannot perform better than it in terms of distortion (around 27 liters, if extended to the rear even more).

 

[fineMen]

Using no-name drivers and non ported enclose doesn't allow to generalised that a sub with the same base dimensions of a R3 cannot perform better than it in terms of distortion (around 27 liters, if extended to the rear even more).

I'm in general a bad guy, and u bend the rules in extending dimensions to the rear. I say, visually appealing is a must. Whatever, let's see what comes out , please report.

 

[thewas]

I'm in general a bad guy, and u bend the rules in extending dimensions to the rear. I say, visually appealing is a must. Whatever, let's see what comes out , please report.

I don't , the mentioned 27 liters are without extending from the rear. Looking forward to your comparison measurements, I am not building a sub because my bought ones work fine and probably still easily beat the R3 in terms of distortion in the bass.

 

[abdo123]

Interesting, so your R3's had less distortion below ~80Hz than DIY subs? That sounds strange. It's been my understanding that once you are in the subwoofer frequency domain, it's purely mechanical, as in, you're displacing air volume, and that's really it. DSP's EQ/limiting and port chuffing/resonances can highly skew measurements too. What DSP, amplification, drivers, and enclosure are you using? EDIT: Did you put a HPF on your R3's? That could be the culprit.

Link to calculator. Of course this is an oversimplification compared to full on subwoofer design software.

Piston Excursion calculator

www.baudline.com

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ported subs are usually very dirty with regard to distortion. sealed subs would outperform it for sure but you're still limited by the fact that low frequencies require a lot of mechanical movement so without niche drivers it's hard to get the distortion below 1%. Luckly at these frequencies even 10% is not audible. This is my 12-inch sealed sub at around 86db @ 1m.

 

[fineMen]

I don't , the mentioned 27 liters are without extending from the rear. Looking forward to your comparison measurements, I am not building a sub...

0,2 x 0,34 x 0,42 = 28 liters external ~ 19 liters internal with 3/4inch panels, not accounting for wadding (+), bracing (-) and driver recessment (--).

Anyway, as with the measurements requested above, a purely 'theoretical' debate. I better do my own homework.

... still limited by the fact that low frequencies require a lot of mechanical movement so without niche drivers it's hard to get the distortion below 1%. Luckly at these frequencies even 10% is not audible.

Exactly, but not just movement, but secondary effects as field modulation, cone/surround bending etc by excessive currents and pressures by excessive equalization with excessive cone area per volume.

Q was if the R3 can be beneficially supported by a stand double used as a sub. IWhen it comes to me, I'm not willing to pay for possibly competent p/a drivers with neodym magnets of some strength and an accordion surround (BMS: 300$+). I rather misuse the space with a stand as a stand ('hate it) plus bigger subs already at hand elsewhere in the room.

 

[thewas]

0,2 x 0,34 x 0,42 = 28 liters external ~ 19 liters internal with 3/4inch panels, not accounting for wadding (+), bracing (-) and driver recessment (--).

You don't want a loudspeaker stand for the R3 that is only as high as them (42 cm high), my above calculations were 1.6 x 3 x 5.6 dm = 26,88 liters (with already 2 x 20 mm being correspondingly deducted for the panel widths).

Anyway, as with the measurements requested above, a purely 'theoretical' debate. I better do my own homework.

Looking forward to them.

 

[holbob]

ported subs are usually very dirty with regard to distortion. sealed subs would outperform it for sure but you're still limited by the fact that low frequencies require a lot of mechanical movement so without niche drivers it's hard to get the distortion below 1%. Luckly at these frequencies even 10% is not audible. This is my 12-inch sealed sub at around 86db @ 1m.

Do you listen at 49db?

 

[Lbstyling]

Yes, I built subwoofers double serving as stands. These, despite using two 8" woofers each with some serious amplification and DSP showed in combination with the R3s three to 10 times the distortion of the R3s alone. While the R3s were, when playing alone, equalized to have the same frequenc response as when supplemented with the subs.

Only benefit was an extension down to 25Hz with the subs as opposed to 35Hz with the R3s alone.

Forgive me, but you must have either built them wrong (no stuffing, leaky cabs, ported wrong, resonances unaccounted for etc) or they are low quality drivers.

I own the R3s crossed to 2 x TD15m drivers.
Distortion drops big time below 400hz. I can't even measure it!

Are you using ground plane measurements?

 

[fineMen]

Forgive me, but you must have either built them wrong (no stuffing, leaky cabs, ported wrong, resonances unaccounted for etc) or they are low quality drivers.

I own the R3s crossed to 2 x TD15m drivers.
Distortion drops big time below 400hz. I can't even measure it!

Are you using ground plane measurements?

I'm afraid you didn't consider the original challenge. Same volume as the R3 alone, so that the added sub serves as a visually appealing stand.

 

[ROOSKIE]

I used the R3 and a few other speakers on 8" ported DIY subs as stands and 10" sealed subs that use a proper bass bosst to lift the roll of. @fineMen and others, When you folks design sealed subs, plan to use bass boost to get the extension you want. (and thus use a beefy amp)

They don't even have close to the same output levels as either set of subs. Forget about. This is physics. This comes up often.
Low HD distortion is not exactly the same as output ability, dynamic ability.
My R3's had great harmonic distortion character above 50 or 60hrz.
Below that they are great for a 6.5" and yet like a great 6.5" they start pumping some junk fast. The 30-35hrz region is 50-100% HD distortion dpeneding on level and exact frequency. It likley sounds like 'output' due to pumping out some serious 70 and 105hrz extra stuff, +some IMD frequncies.

That said they are super decent on their own for a 6.5" system. Just realistically 2, 6.5"'s are equal to about 1, 8". But then add in the extra excursion of a dedicated 8" subwoofer and you could have a situation where that 8" outputs what 3 or 4 KEF R3 6.5" drivers can. I don't know. I need subs with just about any monitor speaker to really drive electronica and bass lines and other goodies, (though I certainly can really enjoy good monitors sans subs... it ultimately just is not the same )

 

[gegegege]

they went on sale at bestbuy for $1100, all gone in under 2 hrs. Insane price, especially for the white ones.