I have recently decided to experiment with a subwoofer for my system (mainly audio, little HT) and dug out my old Definitive Technology SUB1000 from my now retired HT system. My room has a quite inconvenient L-shape with ver few options for speaker placement. I have used my kid’s drawing program to describe it as best as I could below where my two ELAC Navis ARB-51 active bookshelf speakers are the red squares (too far apart but little I can do about it, also for wife-acceptance reasons). The sub is currently in the purple square and I sit in the black L on my corner sofa. Grey squares are other potential placement options. The big brown rectangle is a massive brick fireplace. I forgot to draw a large cabinet sitting directly left of the sub in the guest dining area of my room (ie no man’s land).
Considering the improved SQ despite (i) potentially poor current placement/tuning and (ii) decidedly poor sub quality (much more of a big HT boomer), I have now just bought a used REL T7 (1st gen) which I will be getting next week.
Questions I have are:
1. If using one sub only, where would you put it?
2. If using two subs, would you use the two grey positions or right grey and purple? I read that opposing “corners” can be helpful to get rid of nodes
3. Do you see a lot of value in adding a second decent sub (thinking REL T5 to sit in the right, closed off area with the T7 to power through the more open space on the left)? IMO keeping the DefTech sub will only negatively affect the SQ of the T7.
So I’ve got a REL T7 about two weeks ago and tried the crawl method. From the possible options, the one left of the sofa (purple) was clearly the better one from a bass perception POV. I have taken a bit of time to blend in the sub with my ELAC actives and am fairly happy with the result now - lots more low end without feeling it is coming from the sub, ie what you would want.
Clearly my room is far from ideal when it comes to acoustics and there are some clear peaks in freqs so I am now looking into both room correction (miniDSP) and a second sub (the DefTech is going back to the attic after hearing the REL).
I guess the fun kinda stops when you’re “happy” hehe, so I should be glad it’s (a lot) better whilst not perfect :-D
Anyways thanks for the help so far and please keep the advice coming, e.g. regarding room correction. I am running a streaming DAC via XLR into a tube pre then XLR into actives and RCA into sub. This is making it hard to find a suitable room correction system…
2 .Understand and mapping a rooms bass modes and nulls is easily accomplished using the previously mentioned crawl method. Whether using one sub or more the crawl is a terrific first step that only needs to be once.
3. Value, yes. This will most likely be a function of trial and error unless you have equalization and room optimization control such as described in jrpnde's Soundoctor paper. David Hall's Digital Drive and DD Plus designs offered most of those parameters using automatic / manual software and a test tone CD to plot both the mains and the subs. The point is, even mismatched subs with basic controls when given a processed signal can add sonic value to a low frequency system. Keep your subs.
4. Put on some Prince, turn it up and dance with the wife. All the best.
+1 for the listening location placement and crawl around; Make sure you stay close to floor level; it does make a difference. And be prepared to be surprised as to where the sub will sound the best; location may be counter-intuitive.
First, place the subs where you would sit to listen. Then move around the room to the positions which sound the best to you. Then move the subs to those positions. They will now sound exactly how you liked them at your listening positions.
I use 2 DefTech Supercube 4000's, they are good for music very quick. I tried 2 x SVS for lots more money but no noticeable difference. I mount them on bookshelf speaker stands for a much better balance than on the floor. You can feel them slightly and evenly more than hear them, I set one at 40Hz / 23 volume and one at 80Hz/ 26 volume , both about 0.5 meters from side walls and 1 m into the room. Mine is a very difficult and quite small 3.3 x 4.5 m room.
The use and placement of a sub(s) has to be one of the most discussed topics in this forum. Placement, room acoustics, and a lot of other factors come into play. The brand and model of the sub have some importance but not as much as other things. Millercarbon offers good advice. I have posted this link many times. Whether just getting into the use of subs or not, it is a very useful source of info...if you have the patience to read it.
I use just one REL sub and found that where it sounds best isn’t as simple as by the couch or where it can be felt through your butt. A difference of two feet or four inches from the wall or which way the cone faces makes the listening area devoid of bass or the response lumpy or even moves the bass to the next room. Or it can deliver the goods when right. Experiment. Inches matter.
OP the Arrays or swarms can use cabinets as small as .75cf. 4 small front firing or even ported cabinets will amaze you. BTW you can hide a .75-1.0cf box pretty easy. They are small and very effective.
James Romeyn was hooked up with VMPS for over 25 years the company closed and of course the staff moved on. He was a huge promoter of Class Ds in the very early days to with Hypex 400 modules too. There are a lot of them still out there made by his hand...
Study a lot more about DBA. All the "one sub" people are about 20 years behind the times. Instead of learning the physics and psychoacoustics that makes a DBA work so well they persist in trying to fight physics with DSP and tube traps. The principles that make a DBA work so well are the same as will get you the most possible from fewer subs. Namely, asymmetrical placement.
Another one the old school laggards miss, a great deal of the boom and other acoustic problems is due to speakers being coupled to the floor. Use effective isolation like Nobsound springs or even better Townshend Podiums and you will be shocked how much of this "room acoustics" problem goes away.
Basically the choice you have is do you want to be the kind of audiophile who does what works, or the kind who does what everyone else is doing? Logically, every time something better comes along nobody will be doing it. You will remain mired in the past. Think about it.
The Duke I referred to is the manufacturer/designer of the 4 sub swarm, but there are a few threads, one started by me, where he replies on using these principles with 2 subs...
I am a little puzzled by your opinion on second sub. Yes, it probably would require room correction by eg MiniDSP (between pre and subs), but presumably having two subs in “opposing” corners should help in smoothing out the general room response.
You don’t have opposing corners, really, you have complex modes that include all of the open space.
Or are you just concerned that room shape + mains + 2 subs would be too complex? It seems these days a bit of REW + Dirac shouldn’t be too hard to manage, but I am inexperienced.
I think if you do 1 sub right you’ll be exhausted and happy. Take a look here though if you want to see what’s involved in optimizing multiple subs:
While I really like the app note I tune my subs to peak between 20Hz-30Hz and descend about 1.25 to 1.5 db/Octave until the crossover point. I find this much more musical than flat. JL Audio and Dirac seem to agree with me.
Last bit of advice: 1 sub, well integrated, is glorious. Most people get 1 sub and cant' do it well so go looking for more ways to fix their problems. I assure you, if you get 1 sub working well, EQ your two mains to match each other, you'll be in a really good place.
I found the threads on DBA and it sounds interesting but is meant to use 4 subs, which option is definitely not even close to being on the table here. How did you apply the principles with two subs? Or where would you suggest to place two on my artfully drawn plan of my listening room? Right grey and purple?
Lol @oldhvymec I am just trying to get a little bass extension and free up my 5-1/4’’ woofers to focus on mids, not get gut-churning bass, hence the switch from DefTech to REL ($300 btw). Though I did manage to seriously worry the missus when I once dimed the DefTech with some bass test tracks 😬
The ELACs have a high-pass/crossover setting (choice of 60 or 80hz, currently at 80) and also the option to “EQ” with a switch +1/0/-4dB for each of HF, MF and LF so I have set the right one at -4dB for LF to account for the corner placement. That way it’s not boomy.
As to your questions about wall/ceiling mounting and bass traps, I think you already know the answer 😂 The speakers are tolerated where they are. Previously I had one where the sub now is, but just off the cabinet, so I could sit in the other portion of the sofa and have both speakers closer together (current toe in is 45 degrees) and with no walls/corners directly behind. But that was deemed ungainly lol. And I am not moaning - this is our reception area for guests so it cannot be turned into a technical audiophile listening room. I am looking into “artistic looking” room treatments but with little hope. (NB: behind my current listening position is a window and there are two more on the right wall, so there it just makes things worse and prevents room treatment due to lack of surface, blinding the windows with Rockwool not being an option 😅)
I am a little puzzled by your opinion on second sub. Yes, it probably would require room correction by eg MiniDSP (between pre and subs), but presumably having two subs in “opposing” corners should help in smoothing out the general room response. Or are you just concerned that room shape + mains + 2 subs would be too complex? It seems these days a bit of REW + Dirac shouldn’t be too hard to manage, but I am inexperienced.
One sub. Set on it or put it right behind your sitting chair. That is what you're looking for. You want to feel it through your bottom. You picked the right type of sub.. Now add about 100lb on top of each sub or like I said, set on it.. It will really couple and rattle the joint..
Wold you consider wall or ceiling mounting in front of the fireplace?
Next to the couch IS the best place for the sub. I don't think adding a second sub is going to be worth the effort to get right. I DO think that you are going to need EQ or room correction to get any of this right. You need EQ to balance the main speakers and high pass filter them. This will reduce the problems you are going to have with one being very close to a wall and the other not.
To integrate that single sub you'll need a good DSP based EQ to clip strong room modes and blend them in with the mains. Otherwise you'll probably be caught between muddy/boomy bass and no bass. How exactly you do this depends on the rest of your system. Roon can help you, as can devices from miniDSP, or you can get a receiver with it built in.
If you were up for room treatment, I'd suggest it on the right and behind the couch, and big bass traps on the two corners on the left. I assume due to other circumstances none of this is an option. :)
one sub can work fine if you have a single listening position and have the flexibility to place the sub wherever it needs to go..l prefer 2, was guided by Duke with the key being asymmetrical placement...there is lots of debate on this, but I stuck with Duke's advice and very glad I did..
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