Question about cabling up a REL sub using high level connection

londonscottish

Standard Member
Hi all, I'm currently using an old receiver (a Yamaha RXV 673) to play music (and only music) in 2.1 mode. No other reason that it's was left over from an install that I've replaced. Most of the time its streaming extreme quality Spotify via the optical input.

The speakers are Monitor Audio Gold bookshelf speakers and a Tannoy HTS sub. Again, the sub is a leftover and something of an afterthought.

I was in Richer Sounds the other day buying some stuff and I idly asked them if it would be worth replacing the receiver with a proper dedicated audio amp that ran 2.1.

The fella suggested sticking with the amp but upgrading the sub instead with one that ran a high level connection - he pointed me at an ex-demo REL 7.1 as an example

I've read the excellent guide on here on high level connection vs LFE/phono and get the concept but I have two questions;

Q1 - do you think upgrading to a £4-500 sub running a high level connection is likely to make a significant difference to the audio quality over the set up I have today?
Q2 - when wiring one, do I just add the wiring to one pair of the existing posts I'm already using for one of the Monitor Audios/
 

Yorkshire AV

Active Member
AVForums Sponsor
generally speaking (though do check on REL's website as they have brilliant setup videos) - when a single sub is being used in a stereo setup:

Red wire to Right + terminal
Yellow wire to Left + terminal
Black wire to one negative terminal

NOTE - this is the case for certain class of amps - if you get a hum, you may need to float (disconnect) the black wire or use an unused RCA port to connect to an unused input on the REL for earthing matters.

Subwoofers add much more than just a bass boost - I think you'll be pleasantly surprised once you've dialled it in properly :)
 

londonscottish

Standard Member
generally speaking (though do check on REL's website as they have brilliant setup videos) - when a single sub is being used in a stereo setup:

Red wire to Right + terminal
Yellow wire to Left + terminal
Black wire to one negative terminal

NOTE - this is the case for certain class of amps - if you get a hum, you may need to float (disconnect) the black wire or use an unused RCA port to connect to an unused input on the REL for earthing matters.

Subwoofers add much more than just a bass boost - I think you'll be pleasantly surprised once you've dialled it in properly :)
Thanks. Makes sense.

And I can see the attraction of going for this sort of connection. Apart from anything else my MA's will now receive the full range of frequencies - the guy in the shop was trying to make this exact point.

Maybe I should get a s/h REL 5.....decent upgrade for £300-ish.

The 7 was very tempting but its a lot of money.
 

rccarguy2

Well-known Member
There is no benefit of using high level connection to your sub, sending full range to sub and speakers if you have a Avr

Rel is stuck in the past with antiquated ideas.
 

gibbsy

Moderator
REL make excellent subs for music. They are fast and very precise. The T Series is their crossover subs if you like and are aimed at both HT and music customers. They do not have the slam that many want for HT bass shaking adventures.

As for you using a high level connection with the Yamaha AV amp you are not going to benefit at all for substituting the low level LFE for the high level. An integrated stereo amp would certainly do so but it's not worth the bother with an AV amp with stereo music. Stick with low level LFE.
 

Gasp3621

Distinguished Member
The fella suggested sticking with the amp but upgrading the sub instead with one that ran a high level connection - he pointed me at an ex-demo REL 7.1 as an example



Q1 - do you think upgrading to a £4-500 sub running a high level connection is likely to make a significant difference to the audio quality over the set up I have today?

Check out BK XXLS400, it also offers high level connection and due to larger size is lot more capable to give fuller sound and depth even for music this has been noticeable as we have seen members comparing REL T5 (8") and SVS SB1000 (12"). XXLS400 has been one of the most popular picks over 10years here at AVF, especially for 100% music or 50/50 music/movie use.




Upgrade the amp at some point aswell, cause you have very good speakers even if older gen Golds and i don`t think V673 does justice for them! Contact hifi shops like Audio-T which will give you home trial for integrated stereo amps example, when you have the funds to buy. Then you can compare the amp to your receiver at home, no blind buying and no risk.
 

Mr Wolf

Well-known Member
I've used a high level connection for 2-channel with a REL sub in various systems over many years. In my experience it can work really well with the right speakers but only at relatively low listening levels. The issue with it is that it sends a full frequency range signal to the speakers which, depending on your listening level, can cause them to run into distortion trying to play deep bass. At high volume levels all normal speakers benefit from being high passed to save them from trying to play very low frequencies that are better handled by a sub.

If it were me I'd probably be using a 60Hz crossover in the AVR with the line level sub out and, at that price point, be going with a BK-XXLS400 instead as it's more sub for less money.
 

Dobbyisfree

Well-known Member
Agree with @Mr Wolf entirely.

My personal additions... I've played around with high level connection and tried it with many different subs and amp/speaker combinations.

Then, once I had an AVR with Audyssey XT32 and Sub EQ HT, subwoofer (or subwoofers) on low level connection and listening in stereo with EQ switched on and midrange compensation switched off. It was a thousand times better.

I know some sub manufacturers are full of the "it aligns the signals and timing etc etc" but when it comes to it, you're (a) not getting a flattened response from the sub (b) not crossing it over as cleverly as the AVR (c) timing not aligned as well as the AVR and as Wolfy pointed out (d) the speakers are still struggling to cope with the sub-bass.
 

rccarguy2

Well-known Member
Agree with @Mr Wolf entirely.

My personal additions... I've played around with high level connection and tried it with many different subs and amp/speaker combinations.

Then, once I had an AVR with Audyssey XT32 and Sub EQ HT, subwoofer (or subwoofers) on low level connection and listening in stereo with EQ switched on and midrange compensation switched off. It was a thousand times better.

I know some sub manufacturers are full of the "it aligns the signals and timing etc etc" but when it comes to it, you're (a) not getting a flattened response from the sub (b) not crossing it over as cleverly as the AVR (c) timing not aligned as well as the AVR and as Wolfy pointed out (d) the speakers are still struggling to cope with the sub-bass.

You'd think rel would wise up. Seeing them still give out that old method shows lack of knowledge when it comes to bass.

That and no mention of time alignment or eq (antimode etc) knowledge from 1990
 

Dobbyisfree

Well-known Member
Kind of.

For people with just a normal amp and no additional EQ, they don't have the option of a computer helping them out with it.

Problem is, with manufacturers that leave in the high level connection, e.g. REL, BK, SVS, they are just adding cost to the units. When, in my opinion, the majority of sub purchases are by people that have separate EQ and don't need the sub to have a high level input or crossovers (and in most cases, any crossovers for low level either!).
 

Mr Wolf

Well-known Member
Obviously this connection has no value in HT use but some people simply want to be able to connect a sub to a pair of speakers for 2-channel music to a basic amp that doesn't have a line out.

It was useful to me once as my Yamaha AVR bypasses the internal crossover in its highest SQ mode (Pure Direct) which I liked to use for 2CH music. As I also wanted to keep the AVR permanently connected via the sub-out for HT purposes this connection provided a really useful option that actually worked extremely well at low to moderate listening levels with my tower speakers that were quite happy to be run full-range in this application.
 

Dolus

Active Member

Dobbyisfree

Well-known Member
Just posted up on AVS
REL 3D Subwoofers Home Theater Setup...

Depending on your point of view on high level V low level connection, you will find this interesting or laughable.


Interesting. But, on from discussion earlier, you'd need to put filters to the speakers too. Not many people's amplification would have the headroom to still be sending full signal to the speakers.

Some REL's older models, e.g. the Strata, had a high level input and output that was "bass cut". As you shift the crossover in the sub it adjusts what the sub does and what is sent to the speakers.
 

rccarguy2

Well-known Member
Interesting. But, on from discussion earlier, you'd need to put filters to the speakers too. Not many people's amplification would have the headroom to still be sending full signal to the speakers.

Some REL's older models, e.g. the Strata, had a high level input and output that was "bass cut". As you shift the crossover in the sub it adjusts what the sub does and what is sent to the speakers.

That's high pass function however that still means the amp is still amplifying that.

Best to use outlaw icbm-1 between pre and power route our from the ICBM
 

Dobbyisfree

Well-known Member
That's high pass function however that still means the amp is still amplifying that.

Best to use outlaw icbm-1 between pre and power route our from the ICBM

Really? It's an active subwoofer though?

May be interesting for @Lensman5d to comment as I think he tried it out.
 

rccarguy2

Well-known Member
Really? It's an active subwoofer though?

May be interesting for @Lensman5d to comment as I think he tried it out.

Somethin like svs sb12+ has high pass filter on high level and low level

Some analogue integrated amps have high pass function, emotiva and outlaw.

Or there's the outlaw ICBM-1, low level,.its basically 5.1 line level bass management bit can be used in stereo and sub system. I've got a ICBM
 

Dolus

Active Member
I've got a ICBM
Me too, where's yours aimed at? :)
1200px-Titan_II_launch.jpg
 

password1

Distinguished Member
There is no benefit of using high level connection to your sub, sending full range to sub and speakers if you have a Avr

Rel is stuck in the past with antiquated ideas.
Rel recommend the same signal to the sub as the main speakers. It eliminates any timing issues.
 

londonscottish

Standard Member
Thanks for all the replies, fellas. I could understand about 70% of what was being said, the rest went completely over my head.

On balance, I decided to resist the cheap ex-demo REL as I'm not sure it would make that much difference - at least not £450's worth. And I've got plenty of other ways of spending it.
 

password1

Distinguished Member
any avr is capable of playing music and 'up to the job' but they won't sound as good as a stereo amp at the same price.
 

londonscottish

Standard Member
any avr is capable of playing music and 'up to the job' but they won't sound as good as a stereo amp at the same price.
Exactly. The amp was just something I had lying around. I re-used it purely for convenience. Hence asking the bloke for an audio amp recommendation whilst I was buying a TV bracket.

He just got fixated on subs. Quite possibly because he was trying to shift an end of line ex-demo REL......

.
 

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