Subs n Lows

[Mike Hanson]

Well, I have a set of huge JBL 4331B's. The thing is, if I place them for best general response there is, in my room, a large suck out at about 40 Hz. As you say, an inexpensive sub will not do. Instead I use one of the 4331B's as sub for a set of KEF R100. The R100's is placed for a good general response, mostly by ear, and the sub is placed where it gives an as straight as possible measured response from 20 Hz and up to about 200 Hz. Then the tweaking starts...

How do I know the suck out is at 40 Hz? Well, you guessed it. Measurements.

There are definitely cases where measurements are utterly crucial. For whatever reason, I've not encountered a problems this significant. Who knows, though?... Maybe I'll setup my calibrated mic and REW someday, only to find out my system sounds like crap.

 

[Kev67]

.1/LFE —> Subwoofer out phono/rca socket.

Low Level Input —> Pre Out phono/rca socket/sockets. If the Sub only has 1 low level input phono socket you can use a Y-cable or Y-adapter.

There are other ways to connect like XLR and also Passing Thru signals but I was keeping to the standard types/ways to use a subwoofer. There are also things to learn such as crossovers, filters, phase, input voltages, dsp/eq etc. best to walk before running and follow a basic guide to get up and running.

Superb, Thanks very much.

 

[Mike Hanson]

The Cornwalls use a passive radiator, which is not that much different from a port, so the bass can be improved of they're high-passed above the resonant frequency (~35Hz) and a driver is used for the sub-bass range.
Besides, if your room produces interference dips in that range using one or two subs will also address any ringing that masks bass detail.

The Cornwall's don't have a passive radiator, but rather three ports in the bottom front. (That's why they work so well against the wall.) Perhaps you're thinking of the Forte, which does have a passive radiator on the back.

Yes, I'm sure I could make my system better, by adding a second sub, doing a bunch of measurements, getting rid of all the furniture that makes it into a livable space for normal humans. By converting it into a pure, perfect listening room, I'll also have lots of time to listen to music, because my wife will divorce me.

Fortunately, my current setup is leaps and bounds beyond "good enough", so I'm definitely not suffering. And my wife and I get along just fine.

 

[Amber Audio]

i

Thanks. Which sub is that?

I looked at the REL subs you recommended, eg T5i, T5x, T7i and T7x. None of them had Left or Right inputs. I'll put a few pics below as examples. I looked at a few other REL subs as well, and none of them had Left or Right inputs either so I assumed this was uniform for REL.

T5x

TZx

T5i

It’s from a Carbon Special, a mate just bought a pair and my dealer has some being traded in, am mulling………Defo not doing the triple stack though

 

[Paraheadache]

An alternative is that I get a Y cable that will bring two RCA outputs from my Preamp into the single RCA input on the REL?

... Don’t do that! It would result in the main speakers reproducing mono. And although I doubt that it would happen in this particular case, with some preamps doing that might even result in damage, eventually if not sooner, since you would be shorting the preamp’s outputs for the two channels together.

(Screenshot from audiogon discussion forum)

 

[Paraheadache]

Any REL sub I've looked at I have never seen a Left and Right phono input.

You can use a single RCA interconnect from either L or R on pre to the single low level input. It still sounds good, or look for a used S2, S3, S5.

 

[Amber Audio]

Superb, Thanks very much.

If you post your amp make and model with a picture of the rear connections, folk can confirm what connection/cabling option would work with a particular subwoofer model, there are all sorts of combos of inputs on subs, generally more £ = more connection methods it will take/provide.

If you’re averse to high level then typically these are the 2 common options:

Amp has a phono socket out marked Sub/Subwoofer —> connect to the .1/LFE socket on the Sub​

Amp has Pre Out phono sockets Left and Right —> connect to the Low Level socket on the Sub. If there are 2 sockets on the Sub they will typically be marked Left and Right, go with Left to Left​

There are all sorts of situations where you do something funky with cabling, I share a pair of Subs with 2 systems which means extra cables, but with a modern sub and amp the above 2 options should do the job.

An example where you’d use a Y-Cable or Splitter is on a really old Sub, a lot wouldn’t come out of standby with just a single cable, they needed a kick up the butt with a bit more ‘“oomph” the dual connection gave - nowadays no such issues.

 

[Colin L]

Superb, Thanks very much.

From the RCAs on the back of my DAC (same thing if from a Pre). Just like this. For the left hand sub of my pair

 

[Amber Audio]

... Don’t do that! It would result in the main speakers reproducing mono. And although I doubt that it would happen in this particular case, with some preamps doing that might even result in damage, eventually if not sooner, since you would be shorting the preamp’s outputs for the two channels together.

(Screenshot from audiogon discussion forum)

Unlikely to be a problem with mainstream modern kit, it‘ll use buffers or have high enough output impedence.

If anyone has the slightest doubt the best bet is to conact both your amplifier manufacturer and subwoofer manufacturer and pose the question. Dealers and forums are good sounding boards but best go to the horses mouth with safety questions.

 

[Kev67]

If you post your amp make and model with a picture of the rear connections, folk can confirm what connection/cabling option would work with a particular subwoofer model, there are all sorts of combos of inputs on subs, generally more £ = more connection methods it will take/provide.

If you’re averse to high level then typically these are the 2 common options:

Amp has a phono socket out marked Sub/Subwoofer —> connect to the .1/LFE socket on the Sub​

Amp has Pre Out phono sockets Left and Right —> connect to the Low Level socket on the Sub. If there are 2 sockets on the Sub they will typically be marked Left and Right, go with Left to Left​

There are all sorts of situations where you do something funky with cabling, I share a pair of Subs with 2 systems which means extra cables, but with a modern sub and amp the above 2 options should do the job.

An example where you’d use a Y-Cable or Splitter is on a really old Sub, a lot wouldn’t come out of standby with just a single cable, they needed a kick up the butt with a bit more ‘“oomph” the dual connection gave - nowadays no such issues.

Here is my Quad Artera pre. The only outputs not currently in use are the pre outs, the XLR and Aux are used as connections with other bits of kit.

 

[ToTo Man]

I will in the near future.

But one cannot make full advantage of using subwoofers unless the mains are high-passed.
This will significantly ease speaker positioning and relieving them from low- and sub-bass duties will reduce distortion and improve max SPL capabilities.

The problem is finding a 2-channel integrated or preamp with bass management, there aren’t many around, and I don’t want to use a miniDSP.

The biggest audio revelation I ever had came when I was in my late teens and added a pair of subs to my multichannel system. My Marantz SR7300 AV Receiver only offered very basic 80Hz, 100Hz, 120Hz high-pass options and, after some A/B'ing, 120Hz was definitely the best and essentially eradicated all of the port boom from the Wharfedale Valdus 500 I was using as my mains at the time.* I was amazed by how much the transient attack and clarity of the midrange improved, relieving the mains of the low frequencies really did wonders for them.

* Don't ask.... I fell in love with these speakers after auditioning them in RicherSounds as a 10-year old and received them from Santa a few weeks later. Despite their massive flaws, they were responsible for many of my favourite music memories.

 

[andyr]

Thanks. Which sub is that?

I looked at the REL subs you recommended, eg T5i, T5x, T7i and T7x. None of them had Left or Right inputs. I'll put a few pics below as examples. I looked at a few other REL subs as well, and none of them had Left or Right inputs either so I assumed this was uniform for REL.

Perhaps buy a non-REL sub?

 

[Kev67]

Perhaps buy a non-REL sub?

Yeah that was the route I was going down if you look upstream lol. I posted some examples of several I was looking at, but I guess REL are the brand that people who know about subs are enthusiastic about. I'm just happy for people to provide hints, tips and recommendations.

 

[andyr]

... but I guess REL are the brand that people who know about subs are enthusiastic about.

Sure, that's one way of regarding them!

I would say people who buy RELs know very little about subs - but have drunk the REL Koolaid.

 

[music fiend]

Sure, that's one way of regarding them!

I would say people who buy RELs know very little about subs - but have drunk the REL Koolaid.

Or tested them against other brands and found them to be better for music regardless of specs per pound.

 

[music fiend]

i

It’s from a Carbon Special, a mate just bought a pair and my dealer has some being traded in, am mulling………Defo not doing the triple stack though

Go for it!
I just have a pair of the old R528SE that also have carbon drives and it was one of my best buys ever.

 

[camverton]

Many brands have an enthusiastic following, often by people who have bought them, but unless people have also bought other brands it’s difficult to put to set too much store by their enthusiasm. The problem is that it so difficult to compare subs; they can be large, heavy and their success depends greatly on the room and how they are integrated.

It might be better to pay more attention to brands that have problems reported and proceed with caution. It is natural to be enthusiastic about our own choice of product but that doesn’t necessarily make it the best fit for anyone else.

 

[Amber Audio]

Sure, that's one way of regarding them!

I would say people who buy RELs know very little about subs - but have drunk the REL Koolaid.

You're entitled to your opinion. I'd suggest that for someone starting out and with a limitred budget a REL is a perfectly sensible suggestion - loads available to demo/home loan via dealers and bargains to be had ex-dem or used, because they are so popular it's easy to get advice from actual owners on forums.

Everyone has to start somewhere, once you gain hands on experience you can get into learning about the compexities of setup/positiioning, importance of the room etc.

Beyond REL I think SVS is a great option as a starter sub too, sq on a par with REL and the Phone EQ App makes hearing changes from the listening seat dead easy. They are also fairly common now so similar to REL demo/deals can be had.

 

[tuga]

Yeah that was the route I was going down if you look upstream lol. I posted some examples of several I was looking at, but I guess REL are the brand that people who know about subs are enthusiastic about. I'm just happy for people to provide hints, tips and recommendations.

Still, other people's preferences do not guarantee your own satisfaction.
I you have a dealer nearby it's worth popping in and giving 2 or 3 subs a listen.

 

[Kev67]

Sure, that's one way of regarding them!

I would say people who buy RELs know very little about subs - but have drunk the REL Koolaid.

Be interested to hear your recommendations. As Amber Audio says I'm a novice when it comes to subs so REL might be a good place to start, but I'm open to all suggestions.