This is a review written by Terry Ellis December 2024.

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A simple beginning

If you have followed me for a while you will have seen me review lots of REL Acoustics subwoofers and I will admit I end up saying similar things in all of the reviews about how the REL improved the sound of my HiFi system. This review is no different because the same is true again. There are a number of technical reasons why this happens that I will explain a little about, however in terms of making a difference the Classic 99 subwoofer might be the biggest improvement I have had from a single REL that I have experienced to date and that is very interesting.

The Classic 99

I think REL have designed the Classic 99 to be more than just a subwoofer.  Because its very much intended to also be a piece of furniture that disappears into your home and maybe you would place a pot on top of it or similar more like a normal piece of furniture.  It has what has now become a very “old school” subwoofer aesthetic with the walnut wood veneer finish all around.  Its definitely a homely design, and of course it’s a timeless design too that is very much back in vogue right now for speakers and has been for a few years. Its a world away design from the typical modern subwoofer we see like the REL’s T/9X especially in the red finish I had here earlier this year for review. The Classic 99 I think is quite regal by comparison and I think we see that intent with the gold colour controls on its amplifier plate and I chuckle a little bit to myself because how much I really like the gold coloured controls.

In a nut shell the Classic 99 is a down firing sealed subwoofer with a 12 inch what REL call “amended pulp on paper” driver cone that is driven by a 450watt Class D amplifier, with all the usual REL connections and controls such as high level and crossover and line level or LFE as REL call it. REL offer wireless connection solutions if that works better for you in your home situation rather than running a cable but this is not built into the Classic 99.

You can have all of this REL loveliness for the retail price of £1799 which means it is going to cost you a bit more than even the Special Edition T9X that retails for £1549.  I think this is very interesting pricing and possibly would make your mind up if your trying to choose between them, however if the classic look of a subwoofer suits your home better or if you want the sub to match your Wharfedale or Mission or JBL or any of the other classic looking speakers out there then spending the extra of course makes complete sense.

A Classic conundrum

However do you need to spend more because REL also make the Classic 98 subwoofer that I reviewed around this time last year and thought was fantastic with my Mission 770 speakers. I was more than happy with what the 98 was adding to the system for its considerably lower £1299 price tag, so why should you spend more for the Classic 99.

There are some obvious reasons, when you look at the two side by side there is an appreciable size difference for good or for bad depending on your situation.  The good is a more powerful amplifier driving a larger speaker cone, with the larger cabinet means the 99 will move more air and have more output at deeper bass frequencies.  This can be useful for music, larger rooms, matching up to larger speakers or especially useful if you are using the REL for movies as you will likely want as much bass wallop as you can get. The 99 definitely digs a bit deeper with more output than the 98 I could hear that without needing to do any measuring. However in reverse I have done many Dirac system calibrations for people who live in apartments where they don’t want loads of deep bass so maybe for that person the Classic 98 will be the better choice subwoofer. Its always a balance between what you want and what do you really need, however with subwoofers quite often more is more.

There is another reason to spend the extra for the Classic 99, REL told me its design has been tweaked just a little bit compared to the 98, so its still the same down firing subwoofer with the same slightly thicker more chewy pleasing bass delivery that’s got a lovely flow about it.  Like the 98 it gives you a lovely warming blanket of bass in the room.  But the 99 is supposed to be faster and more nimble more like how a T9X is, so you are supposed to get a double benefit here where the 99 is faster and can translate bass details and nuances better as well as being bigger in output. If that is true and I have no reason to doubt it based on my experience of both the price difference makes sense and is justified.

Some important technicals

For testing I have here the Wharfedale Super Linton speakers which I thought would be a very hard test for the REL as the Super Linton are extremely fast and clear sounding speakers with a fast detailed bass. My first thought was could the REL keep up and would I be able use it how I prefer to with a higher crossover that can really improve a lot with the sound, from bass up to the vocals and more. If the REL was not fast enough to keep up with the the Super it would be obvious as the sound would start to thicken and muffle the vocals showing I was trying to do too much with it or using a too high crossover frequency.

Once I had the Classic 99 time alignment right to audibly match and disappear it could easily keep up with the Super and just one 99 had enough output to balance with both speakers in my room, but having two 99’s would have been better for sure and allowed to do more and get a better result.

Why do I do this and why do we even need or benefit from a subwoofer when the Super Linton deliver very good bass extension down into the low 30Hz according to the spec sheet and my in room measurement?

If you look up the science of human hearing it tells us that as bass gets deeper in frequency our ears become disproportionally less sensitive, so we need far more bass output at deeper frequencies to sound at the same volume as higher frequencies, this is a very important scientifically proven psychoacoustic effect.  So simple logic tells us that even if a speakers spec says bass extension to 10Hz that doesn’t mean they deliver enough output at 10Hz to balance with the rest of the sound or as we will need to hear it balanced.  Often the spec for bass is -6db and we might need +6db to balance so its 12db away from where it needs to be and that is a huge amount of bass difference.  This is just an example but based on the real world scenario.   So adding a subwoofer controlling the amount of bass we have in the room allows us to balance the amount of bass to sound correct for our ears, this is very hard to do with just speakers alone, and impossible at certain frequencies.

More important than this is how bass behaves in a room, because the bass you will be hearing from speakers is never perfectly linear, its always up and down like a mountain range often with big “gaps” or cancellations caused by the room. I have measured hundreds of speakers in hundreds of room its always the same. So subwoofers can be of benefit in 99.99999% of cases because more bass sources in a room so long as they are in phase will help to smooth and even out the bass response where you sit and listen so that can be a huge benefit too for bass quality and detail.

That is one of the big technical advantages in my mind of REL’s high level connection approach because you are not taking a bass source away with a crossover or high pass filter on the main speakers, the speakers and subs all play bass so you have more bass sources, that again so long as they are in phase we know is likely to give us a better result where we sit and listen.

Getting going with one complaint

I setup the Classic 99 in the same spot in my room as when I tested the Classic 98 last year. I know its more in the middle of the room and this is probably not how you will use it at home, but in this spot the sub is seeing less room interaction.  This is important as I get to hear more of the sub on its own and less of the room and it turns out it’s a great spot for bass quality.

Straight away I could hear where the 99 was delivering more output in the deeper bass than the 98 had before because I could run the 98 loud in my extensively acoustically treatment listening room without any room problems. However the 99 was putting out a little too much very deep bass for my room treatments effectiveness and I could hear bass lingering a little bit and causing a slight loss of bass detail and composure. To solve this I used the parametric eq in the WiiM Ultra digital music source and I applied a 2.5 db reduction at 34Hz with a narrow Q, so only a small eq was needed really but like said I didn’t need to do this with the Classic 98. So I can guesstimate the Classic 99 will have about 3db more output compared to the 98 which is a significant difference.

Now of course I didn’t have the benefit of eq listening to the CD player or for listening to records, although vinyl sounded fine. So I have to point out this is where it would be great for REL to develop their subwoofers to offer some eq in the future. Currently its only available in the top of the range No 31 and 32.  It is what it is but it would be a nice addition for future RELs if they could make this work I am sure a lot of people would really appreciate it.

I know REL subwoofers so well by now the 99 only took me about 10 minutes to setup and be very happy with how it was integrated. I listened across a very wide variety of music including modern electronic heavy hitting bass, female vocals, folk music and modern jazz-ish stuff, audiophile stuff, some drum and bass and a real mixture for several days occasionally unplugging the REL to remind myself of what it was doing. I had the crossover set to around 11 o’clock on the dial with about 1/3 high level power for reference of my subwoofer settings. Please see the image for a more accurate reference.

As I said at the start the difference the Classic 99 made to my system sound overall  I would say was massive and funny enough I have been on a little journey with the Super Linton speakers since they have been here for the last month or so. I know they are fantastic speakers but I have found them to be like a little puzzle where I have been trying to work out how to find the magic with them. The extra bass or the REL is exactly what I needed to find it. Great sound is mostly about balance and the extra bass from the REL balanced the systems sound in my room far better for the same technical reasons I explained above.

The on / off test difference

I had been enjoying the Super Linton with the QUAD 33 and dual mono 303 amps without the REL.  I really enjoyed that setup a lot, and I was using the Quad 33 tone controls set to bass +3 which is telling for the sound in my room because I was looking for a more full tonal sound from the very neutral Super Linton speakers, mostly to get a bolder warmer overall sound from them, especially in the vocals.

I thought that with the REL I might be able to turn the QUAD 33 tone controls off for a bit more overall sound clarity but nope, that needed to stay on for the best overall sound which makes sense as your always matching the REL to what the speakers are doing. There is only so much you can do with a REL, the speakers sound and bass is very important too as its sets the baseline, excuse the pun. But it was interesting to test this and and was a great reminder your speakers matter a lot even when using subwoofers.

The difference between the REL being on and off was dramatic and what many would call a night and day difference. With the REL on there was a lot more overall bass pressure in the room which is better for electronic heavy hitting bass music, that is an obvious one. What I think worked really well was the warmer slightly thicker rounded chewy bass of the Classic 99 really helped to flesh out the faster and cleaner, leaner sounding bass of the Super Linton making them sound a lot warmer and sweeter. But most importantly not any slower or less lively or less clear, instead just balancing the overall tonal makeup of the system even better than it was possible with QUAD pre power setup alone.  The QUAD is a great pre power to use with the Super but the REL helped to take the overall system balance further and more to my overall preference and this might be an obvious difference again.

But what is definitely not obvious is how the REL with the higher crossover helped with the vocals, having more upper bass presence also helps the lower vocal region making vocals sound bigger and far tonally full and rich and more rounded and 3D in the room.  I find vocals presented like this are more pleasing and satisfying so more to my taste and this was probably the REL difference I appreciated the most.  The QUAD with bass +3db on the tone control did this too, but the REL took it further and allowed me to control this more.

Also the sound stage improved with the REL on but it didn’t feel bigger or more expanded in my room. What surprised me the most was the space between the speakers felt more open or see through onto any sounds that were being perceived coming from behind the speakers.  This is a difficult one to explain or for me to quantify, I can best explain it as a result of everything in the music sounding more tonally solid and full.  So anything happening “behind the speakers” drums, piano, vocals anything all had extra size and presence about them so they sounded more like they were in their own more 3D space in the room. A great example of this was in the track Birds by Domiqiue Fils-Aime the double bass in this is set back behind the speakers and it sounded very life size in scale with real dynamics and pizazz about it as an authentic instrument being played. I am also thinking of the side singers in Riltons Vänner Schatt matt that is an amazingly produced song. Part way through there are some side singers that almost can sing right into your ears and with the REL on these sounded large and full in size, almost life sized singers being in the room with me.  With the REL off these vocals sounded more like an effect and less like a person so for me again its about using the REL’s bass to create a more interesting more impressive more authentic listening experience.

Also because there is a lot more bass pressure I didn’t feel the need to listen as loud as I normally would for me to feel the music as impactful on my body, this a big win however I still ended up cranking the volume just as much as the listening sessions progressed. Now the music was better balanced and sounded warmer and more full and pleasing it was much less fatiguing and sweeter sounding at louder volumes too.

Turning the REL off and a lot of the fullness and warmth I was enjoying was gone and now the system sounded a little brittle because the balance had changed and the top end stood out more and overall the sound was not as pleasing, or as interesting for me to listen to. What is most interesting about this is the balance of the system seemed totally fine before I added the REL and I was enjoying it a lot and what this shows is you can’t know what you are missing until you have heard it, then you can never un-hear it, or at least it can take some time to forget it.

Yes a lot of this improvement was coming just from having a better balanced amount off bass in the room, any subwoofer can give you more bass, but if the bass is not at the same quality level as the speakers it wouldn’t be as easy to get such a seamless integration between the speaker and subwoofer, especially without the benefit of DSP. What can happen if the bass is not integrating properly is we keep turning it down because we can locate it or hear it as a different bass source to the speakers.  That is when we know work needs to happen or changes are needed maybe and lets not waste the full benefit of what a really good subwoofer can do for a system.   Better to change the subwoofer and or spend more time on the placement and setup

However the big negative of subwoofers is related to their setup, you cant just plonk them down anywhere in a room and expect a miracle, setting them up is a skill and can be a challenge if your new to this so do bear that in mind, so the best approach is don’t blame the sub blame the setup because when you get it right its 100% worth it as it can add so much.

Final thoughts

In summary then, I say this every time, you really cannot underestimate the importance of having enough good quality bass for music and enough is a lot of it. I don’t mean window shaking or teeth rattling, that is not what you want of course.  But look at the science of human hearing and that gives you a great idea of how much our ears want and if its good quality bass you can have more than you might think and your music and movies will sound infinitely better for it.

There is nothing like the experience of feeling the music, where the bass pressure you feel it on your body, its a warm and pleasing feeling thats adds something special to the listening experience. That experience is made so much better when the bass clarity is also very good and you dont even think about until its taken away and then you can’t enjoy that same piece music in the same way as something feels missing, the music now sounds wrong.

The Classic 99 can give you very high quality bass with a healthy does of smooth, warming, pleasing bass characteristics too, a little bit of coloration maybe, just a touch but that is ok with a good amount of output for modest, real world room sizes or home theatre expectations.  Common sense still has to apply here, if you want huge bass you want a bigger sub than this, but for real world living rooms, listening rooms, normal sized homes the Classic 99 or two would be a very fine addition to your system

A Special Performer Award is Pursuit Perfect Systems highest accolade and is in recognition of exceptional product performance regardless of price

For the full specification of the REL Classic 99 subwoofer see their website linked here