Hi, the problem with that type of Rel sub is that the low level connection is only a single connection, so you can only connect it to either the L or R channel output of your amp. So if you want to use a low level connection, perhaps you should consider a different sub with a 2 channel input. Using the high level connection would be better. Traditional forum wisdom is that it’s best to connect this to the speakers, not the amp, although my dealer, who has sold Naim and Rel gear for a long time, insists that connecting at the amp end is fine. You will need to either resolder your speaker cables and fix the sub cables to the same bananas, or consider using stacking bananas.
Have a look at the BK P12-300SB-DF sub, it has a high level connection and independent stereo low level connectors. I have just bought one after looking at the REL T7i to pair with my Neat Iota Alphas and the BK does a great job. BK are British made in Southend and built to order and you will save a considerable amount of money as they do not sell through dealers. I believe they used to build the subwoofers for REL, I use the hi level connection, connecting at the back of the speaker, the cable from the amp plugs in via the banana plug and the subwoofer Neutrik connects to the binding post, so no soldering. BK will make you a hi level Neutrik cable specifically to connect to the rear of the speakers if you ask them and it’s FOC, as one of the conductors has to separated from the other two.
@ChrisSU Thanks a lot for your reply. Very interesting. I never owned a sub before.
Am I understanding this right, that I have 3 options to connect the sub to my system:
Either from left or right pre-amp output to low level input (worst choice)
Share the speaker signals at the speaker end
Share the speaker signals at the amp end
And then there is “soldering” vs “stacking bananas” for option 2 and 3.
Is there any downside to use stacking bananas instead of soldering? (As I mentioned, I want to avoid touching my Tellurium Black with a solder iron.)
Is there any downside to “share” the same signal with the speakers or can it be considered a normal practice?
Now in general: From what I understand, it is always better to use the high level input for HiFi. So this is not a matter of subwoofer type choice, right? Or would you still suggest that I should consider another sub?
@johnt I already had a look at those BK subs. They may be cheaper, but they are HUGE! Apart from the better price, is there any advantage to them regarding the connections that they have or still the same as the REL?
PS Interesting that you still use subs with the Alphas. I thought they have much more bass than the small Iotas. You really must like your music “bassy”.
I do not like bass heavy music the sub just fills in bits that are missing. The BK’s are W x H x D 40 x 46 x 40cm. And the rel t7 30.5 x 36.2 x 38.2 cm. but the BK have a 12 inch woofer the rel has a 10inch.See my post above for connecting to the back of speakers without stackable banana plugs or soldering.
Hi Faye, yes that’s right. If you do go for the Rel sub, I would first try stacking bananas, as this would be a very cheap option to get you started. You would then have to decide if it was worth getting different plugs soldered to your cables, but I would leave this until you are happy that the sub can be integrated into your system and room first. This will also allow you to make up the cables to the exact length required.
If you choose a different sub, BK have a good reputation, although I haven’t used one myself, but they do have a 2 channel stereo low level input.
@johnt yeah, the BK is definitely larger. My GF would kill me…haha. Could you show me a picture how your described setup looks on the back of the speakers please? I can’t imagine any other non-soldered solution other than stacked bananas.
And that wouldn’t be a “BK only” solution with that modified Neutrik cable, right? Could also be used for the REL?
about the BK inputs: how does high level input compare to 2-channel low level input? high level would be still better, right?
@ChrisSU are there any special brands to consider for those “stacking banana adapter”?
Firstly, the connection:
Attach spade terminals to the REL cable and attach these to the terminals on the back of the speaker. This way you can leave the TQ cables unaltered.
Second… “Is there any downside to “share” the same signal with the speakers or can it be considered a normal practice?”
Yes there is a downside, but despite this is is considered to be a normal practice. The problem is that as the bass drivers of the main speakers move they also generate their own electricity (known as a back EMF). this signal generated by the main speakers is also seen as an input to the sub (and amplified by it). This is particularly true of frequencies just below the lower limits of the main speakers, where their cones are less well damped (and hence these are just the sort of frequencies that are made audible by the sub).
Third the REL uses a passive radiator on the bottom:
This makes it very difficult to get the phase alignment to the main speakers correct for playing music (as opposed to use in a 5.1.low frequency effect channel), as the output from the passive radiator is first delayed by the group delay of the power amp, then delayed by the group delay of the REL’s amplifier and finally inverted and further delayed acoustically by anywhere from 180 to 270 degrees.
Deltron make some inexpensive stacking bananas, I would try those. Alternatively, if you connect at the speaker end, you may be able to use spades as Xanthe suggests above. However, this only works if your speakers have a suitable dual purpose connection that allows a spade to be screwed tight, and/or a banana to be inserted into the end. It will not work at the amp end.
This the back of my Iota Alphas, undo the nuts on the binding post wrap the wires around the post or use spade connectors, tighten the nut up and plug the banana plugs back in. The Neutrik lead has 3 conductors which normally connect at the back of the amp, but but Naim prefer the connection at the speakers so when connecting to the back of the speakers 2 conductors goto one speaker and the third goes to the other speaker and then everything goes back to the sub. A normal Neutrik cable has all three conductors bundled together, so you will need one with either an extension cable from the red conductor to the other speaker or the red conductor stripped out back to the plug so that you can route the rec to the other speaker. The BK has continually adjustable phase whereas the REL I believe doesn’t. The best sound I have found is with the Hi Level connection. It will take you a considerable amount of time with lots of tweaking to get the room position of the sub, volume level, crossover point and phase correct, don’t be tempted to over do the crossover and volume or you will end up with a bloated sound and wish you had never got a subwoofer. Maybe use REW and a umik-1 mic to help get everything correct.
@ChrisSU How can I verify if the Neat Iota have such a “dual purpose connection” to screw the spades tight? Is that listed somewhere in the specs?
@johnt Great! Thanks a lot for the picture and the explanation.
Are these Neutrik cables non-manufacturer-dependent? Can I buy any Neutrik cable to make the modification to it? (If I should finally decide to buy the REL I’d rather leave the original cable untouched in case that I should decide to re-sell it.)
PS Thx for all the setup tips! Will consider that mic.
Phase: I just checked. Yes, the REL is missing a continuously adjustable phase. Now from what I understand that continuous phase makes room placement much more flexible? If I only have 1-2 spots in my room for the sub, a continuous phase would be a big advantage, right? That seems to be a big plus for the BK.
The banana should still fit in the end. This is probably the best option as you can keep the plugs on your TQ cables, and they still fit into the sockets as they do now. It worked well for me, but I don’t have Neat speakers, so I’m not sure what the sockets are like.
I would have thought the Neat Iota speakers have the same connections as the Neat Iota Alphas shown in my picture, if it does then the picture shows how the connection is made. The BK BK P12-300SB-DF Subwoofer I have mentioned and use does not have a passive radiator. You can pick a cable up from the bay, they are non manufacturer dependant and are relatively cheap.
1 For the sub, use spades as ChrisSU showed, and put the TQ bananas into the 4mm sockets.
2 Unless you are using a REL sub, low level is actually better and allows better integration of a sub using DSP boxes such as the Antimode 8033s or the miniDSP 2x4 (some of the more expensive subs have this functionality built into their electronics).
3 Only one model of BK sub uses a passive radiator (the one suffixed with ‘-PR’). All the other apart from the Monolith series are sealed box. Sealed box suns are easier to integrate into the main speakers for use with music. (Subs using passive radiators or ported enclosures are more focussed on home cinema use.)
I totally agree, and I would NOT consider this normal practice for best sound quality… you are causing compromises in one of the most sensitive and critical couplings in your system, the connection between the power amp and passive speaker.
For subwoofers I have and would always use (ideally buffered, but with Naim not always possible) the aux preamp output available on many NAC/PSU setups. Do keep this signal cable moderately short however if not buffered, which may limit placement.
Well I think Xanthe summarised it well… if you look at the electrical properties between a quality amp out and it’s passive speaker, you will see that connection is sensitive to variations that would otherwise affect the performance. Adding additional impedance (with its reactive elements) is not going to help… especially as Naim amps don’t (I understand) use a Zobel network in their output.
Here is a text of the considerations between passive reactive speaker and a power amplifier.
@Faye there have been some good technical explanations as to why you should use the lo level over the hi level connections, but in my experience it’s best to use your ears, as the hi level connection in my opinion from my Iota Alphas is superior to the lo level connection from my HICAPDR.
With your ears and your Atom it may be different, but give both connections a try and let your ears make the decision, as it’s all about what your ears prefer. Getting the setup correct and placement right are the most crucial things to a well integrated and enjoyable subwoofer.
If you can, like most things with hifi, try and get a home demo of several different subs or if purchased mail order buy from a company with a good returns policy, and base your decision on your room, the different types of connections, controls, integration etc. and let your ears decide.
Thanks for the info Simon, and Xanthe, what you are saying seems to make sense, insofar as I understand it. I’m just curious as to why Naim’s advice is not in line with this. For what it’s worth, I’ve had my N-Sub connected by high and low level, and if anything, preferred the high level connection from the speakers, but the differences were marginal.