This comes back to my original question looking ast the back of the rell there is no speaker input (Which often there are)
Can someone explain to me how sending the amplified signal from a speaker wire into a line level input of a rel is a things (interested to know is all)
I have always used dedicated sub outs or variable gain outputs from a pre in subs.
Rel’s high level input uses a Neutrik plug/socket instead of bananas. So it looks different, but it’s still a high level input taken from the speaker sockets on either the amp or the loudspeakers.
Ah ok thanks
Hi Stenberg. You are correct and my plans of adding a pair of subs have been scuppered. I thought I might be able to use XLR ports but have been advised by REL that this won’t work as I’ll have no control over the cross over. I can’t see how I can get full signal from my SNAXO. Thanks for your advice.
Pete
Sadly, that makes no sense at all.
Why doesn’t that make any sense Xanthe?
From previous thread on Rel subwoofer. Here a post by Anon:
« But for anyone who’d prefer REL’s thoughts on how to setup their REL products here’s the first paragraph from REL’s Tuning Guide ( Link in previous post) )
“REL products are not traditional subwoofers, but true Sub-Bass Systems. A REL is designed to augment the performance of FULL RANGE speaker systems in order to provide, in certain cases, linear response below 15Hz. A REL will take advantage of the physical room acoustics to provide deep pressurization as no traditional subwoofer can. For best results, the REL should be placed in one of the corners behind the speakers. Remember, we are dealing with True LOW bass pressurization with RELs. Low bass pressurization below 40Hz is best derived from corner placement, where the most linear and efficient low bass can be produced because the subwoofer is able to take advantage of the tangential (corner to corner) axis which is typically the longest distance in a room”
I find it interesting that you follow Naim’s protocols like Naca 5 speaker cable, length and all their other recommendations like a religion; but REL’s guidelines, you just can’t get along with… I’m surprised since they are a very British company…«
REL impressive set up:
That still doesn’t answer the question of why it would be a problem to take a high level signal from the power amp that handles the bass driver in an active system.
The bass amp by definition isn’t handling a full range signal (receives LF information from X/O). From FR’s post it seems as though that will compromise the performance of a REL sub. Maybe still work? but REL seem to be advising that it’s not optimal.
FR’s post gives no explanation of why it might make any difference where the higher frequencies are filtered off.
Seemingly REL sent this advice earlier
Not, but the users have Naim and Rel and finds it’s better to follow Rel recommendations.
If I had the opportunity to hear it driven off the LF 2 I would have tried. I also thought about putting one REL on LF1 and the other on LF2 of the amps but I think that might be difficult to balance and wondered whether it would work?
I’ve given up on it at the moment !
Maybe that, from Rel website :
« A High Pass Filter is inserted between the preamplifier and power amplifier—it lives in our competitor’s subwoofers–– and it cuts out the bass. First, let me make the argument for why these filters exist because, on paper, it sounds attractive. By inserting a High Pass Filter, it is possible (in theory) to restore 3 decibels of loudness to your system and relieve the stress of low bass being produced by your speakers. That is largely true, although one can quibble about whether the speakers involved can truly handle that additional output. But for now, let’s agree that those are the stated benefits.
What they don’t tell you is that by attempting to maximize the decibels, you can destroy the carefully acquired sonic qualities of those speakers you likely paid handsomely for. This is especially true the better your speakers are.
Additionally, here’s why we don’t use High Pass Filters. First, we’re expect our customers have generally made carefully considered choices about what speakers to own. We assume that they listened to a number of speakers and ultimately made a choice to own a pair of speakers that delivers music in the most satisfying way and sounds closest to the way their ears perceive music to sound.«
Just had an email from REL. After looking up my pre amp they recommend using XLR or DIN cables with RCA connectors inputting into the low level inputs on the Sub which will give me full functionality.
Full credit to REL for great customer service! 
That would be the route I would have taken.
Not meaning to be funny, but surely your dealer could have just suggested using the appropriate XLR/DIN to RCA cable from the pre-amp to each subs low level input? Which connection do you use for your crossover?
Take a 12dB/ octave filter set at 50Hz crossover point on a sub with a top frequency response of 200hz (limited by the amp and driver)
First, considering the attenuation at 800Hz:
Crossover filter: 12 * 5 = 60dB
Amp and Driver: 12 * 2 = 24dB
Total attenuation = 84dB MINIMUM.
.
Second, the drivers for subs are specifically designed for low frequencies ONLY. So taking the higher performance Peerless 12" drivers ( NE315W-08 and NE315W-04), both show severe cone break up at 1.6kHz. Cone break up leads to very sever audible distortion, so you certainly don’t want to expose these drivers to frequencies above 800Hz (i.e. 1/2 first cone break up peak).
Third, active subs use class D amplifiers optimised for low frequencies. low frequency optimisation for class D amplifies means operating at lower switching frequencies (typically only just outside the range of human audibility (25kHz to 35kHz, and sometimes even lower frequencies) hence causing massive distortion if the amplifier is fed an HF signal.
Of course the attenuation (84dB @ 800Hz) prevents midrange and higher frequencies causing these distortion mechanisms, but also means that the midrange and higher frequencies make no contribution to the performance of the sub, even if they are present in the input signal. In fact if they were allowed to reach the driver, the result would be awful and horribly distorted by cone break up!
I hope this explains it
Hi Alex,
I use right DIN Output for the SNAXO. I’ve been looking for impartial advice on subs and how to hook up so I’ve been trying to do the leg work myself. REL have been superb in answering questions and being of help.
Cheers Pete
Thanks Xanthe
Pete
