Subwoofer- An itch worth scratching - Cont

I was called last week by one of the dealers recommended by REL. A demo version of their S510 is available for demo. I picked it up today, but without the necessary cables. The dealer phoned Chord and the necessary lead is on its way. I should have it Thursday.

First impressions:

  1. It’s heavier than I expected. A two person job to place it in the truck, but a single person effort to move it into the house.
  2. Out of its box it’s obvious that there is only one location for it: left hand corner next to the left hand speaker. It’s not ideal but space is limited.
  3. It’s a handsome piece of kit, well engineered although the terminals don’t match the manual. This means I’m questioning the suggested connection (SNAXO’s supercap to low level RCA. But which DIN socket - will it be obvious?)
  4. This audition may be pointless. Time will tell.

@Richard.Dane would it possible to open my original thread so that I can post my experiences? See Subwoofer - An itch worth scratching?
If not I’ll be happy to continue this one.

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I’ve never really clicked with the idea of a Sub-Woofer, in a 2 Channel HiFi.
I totally get it for Multimedia AV systems, but why does a 2 Channel HiFi need one?:man_shrugging:t2:

Because it goes down a lot lower in frequency than the stereo loudspeakers do. I have my Quad L sub adjusted to come in below 30 Hz. It probably adds nearly an octave more bass. A key point is that it shouldn’t do anything unless there is that low bass there to reproduce.

This is supplementing my Quad 22L speakers, not my SL2s that I like to use as they are.

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Opened for you.

I would avoid taking the sub signal from the Supercap powering the SNAXO. Take it from the Supercap powering the 52. Make sure the lead is slugged to avoid the Pre out going unstable.

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You haven’t heard how a sub presents the distant kettle drums in the first part of Sibelius’ Four Legends I take it. (Charles Groves’ account, where they are very well recorded).

Not only a rumble, but the depth in the soundstage convinced me. My speakers are standmounts - perhaps this is a factor, I don’t know.


Always go with a high level connection if possible, although tricky if you’re running active which you are.
I’d speak to REL directly and go with whatever they suggest.
A well setup sub is something that a lot of people (myself included) can’t live without once they’ve heard what it does. I think most people struggle to get the optimal placement and don’t necessarily connect it up in the best way possible, and so have bad experiences. It’s a shame because when they’re done right, it really adds so much to the listening experience. It’s not an easy thing to do and much faff is required (normally) to get it right. There’s plenty of ‘how to’ type videos out there to aid in achieving great results, including some on RELs website.
Remember, you shouldn’t be able to identify where the sub is, it should just integrate seamlessly with your speakers and make them sound like they’re doing it all. If it doesn’t and you can hear where the sub is located or it’s not a smooth transition through the frequency range, then it’s probably not right. Good luck and preserve, it’s worth it!


I wouldn’t bother with a low level connection for music. The high level Neutrik connection works so much better, and really is the suggested approach for a music system. If your REL dealer is worth their salt I’m surprised they didn’t recommend that. Take it from someone who has used REL subs for the last 10+ yrs with Naim, and now has two S/510 in a stereo pair (and maybe four next year).

In the beginning I tried a low level connection from a HiCap on a 282 and I just couldn’t get it dialed in. No matter what I did it sounded boomy and bloated. Using the high level connection was a complete game changer.

Edit: didn’t realize you are running active, so I’m not sure how that would work. REL support is really good and they might be able to advise for the proper high-level connection.


Once you’ve heard a properly integrated sub in a two channel system, you never want to listen without it. It’s not about the bass; it’s about space, ‘air’, ambience. It’s addictive.


The only time I’ve used a sub was when I added an nSub to my nSats, with the nSub running of the low level sub outs on a 122x. Without the sub the speakers sounded thin and congested, but with the sub they were totally transformed. As @JosquinDesPrez wrote on the other sub thread, it’s not just about bass. I recall listening to some solo violin music; on the face of it there is no deep bass so the sub should make no difference. However the difference was huge. With the sub there was a real sense of the violin in the room, a sense of the place in which it was being played. I suspect the scale of improvement was so large because of the limitations of the nSats. I was certainly able to get the same feeling of space and ambience when I had SL2s driven my a 300. I’m sure some speakers benefit more than others.


I run a n-SUB with my n-SATs and although I wouldn’t say it transformed them, as they already sounded pretty damn good on the end of a SN3, but it does provide that extra octave that would otherwise be missing. Even more fun :star_struck:

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I ran an n-Sub with my SL2s for a bit. Initially I rather liked it, but started listening more and more without it until I disconnected it completely and never connected it back up. I think that while it added something to the sound, it also rather spoiled the speed and agility of the SL2’s bass performance.


My guess is that your sub was imperfectly integrated with your room and speakers. Sometimes it’s impossible to achieve this, at least without resorting to domestically unacceptable room layouts. I’ve had my N-Sub in a few different systems, and found the same problem with all of them except one, in which it I felt that it really did add a lot, without taking anything away.

I think occasionally you can just get lucky with sub integration. If I ever do it again, I would probably investigate the use of DSP (to the sub only, not to the main speakers) as @Xanthe has described here in order to fine tune the sub.


Thanks Richard - I assume its still a 4 pin DIN?

Thanks for the support BBWan. I don’t have an option of where to place the REL as my listening room is compact, although only two walls are parallel and there two recessed windows and three doors, one of which does not have a door. And the ceiling is low.

@JosquinDesPrez - thanks for your note and comments. Sadly, my dealer, although recommended by REL has limited experience with Naim.
The hi-level connection is problematic at the moment as Neutrik cable as bare wire for binding to speaker posts. Ben at REL has been very helpful and suggested the Naim cable solution. Richard has also suggested that the best Supercap source would be the 52’s rather than the SNAXO’s.

Now that’s a thought I had already @ChrisSU; I’ve already use DSP correction via Roon, albeit with the HouseCurve app rather than Home Audio Fidelity. I hope to migrate to HAF in due course.

The DSP I had in mind was for the signal that feeds the sub only, leaving the signal(s) to your main speakers unadulterated. It involves use of a low level sub connection, with an additional DSP box between amp and sub.

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Ah that is news to me - thanks for the pointer I’ll investigate.

I realise that an active system makes things a little more complicated, as Rel generally recommend that you feed their subs with a full range signal, but is there any reason why you couldn’t take a high level signal from the LF terminals on your speakers or power amp?

Yes, 4 pin DIN pre-out

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Thats a very good question which gets to main reason why i’m keen to try a sub-bass system. Originally, I had 4x135 driving SBLs. When I swapped out my CDS for a NDS I was also persuaded to swap the SBLs for Ovator 600s, but still with 4x135s.

I don’t have enough room in my stacks for an additional 2x135s (or a 250) so my then dealer rigged up a little box so that the 135s drive both the mid range and low frequency units. A possible solution is putting in the REL, although the 135s are capable of driving both units.

At this stage its about testing the concept. Feedback on this forum has been very helpful and convinced me that its worth exploring.

What would be interesting to know is why REL recommend feeding a full range signal when one of the first things the sub’s driver/amplifier does is to filter out MF & HF content from the signal. (Just as with any other cone speaker, not doing this would result in uncontrolled cone break up modes developing).

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