How many subs is too many?

[Tiny]

As part of a wedding/housewarming gift for my Sister in Law and her soon to be husband I am giving them new custom speakers, but I have some restrictions first being my own budget. The second is we are going to use their current a/v equipment for the most part. Lastly is their living room size and shape.

I am not exactly sure what my budget is yet, so lets start with their equipment.
The main and most important pieces are the

1) Receiver/amp Yamaha v659 which has plenty of power for 7 channels.
2) Audio Source 300 watt amp

The room is a very open space the main area is 18x32 but it is an L shaped room with the extension being another 12x14 off the back and in the front where the TV is it has an archway that leads into their kitchen dining area. Needless to say the space wasn't built for acoustics, but it is what I have to work with. For the record we can't put the TV at the other end of the room which would mean 60" of plasma was hanging six inches or so from the shower not to mention there are no outlets on the wall. The floor is also a hardwood laminate over thin underlayment on top of concrete.

My first problem is her current sub, a 10" JVC, no longer gets the job done when it comes to movies or music in that room. It is a good sub, but just not for that room. She also does not want a coffee table sized sub that has to sit in the middle of the room to be effective. She scowled at me for suggesting I make a table sub, (her husband to be quite liked the idea and then figured out he had to change his mind). The also both want cool looking speakers. We decided on a design much like the trapezoidal towers in the parts express project gallery

My thoughts to overcome the subwoofer problem would be to use the bottom cabinet of the four towers to make separate subs pumped through the adcom amp (preamp out of the receiver to the amp and set the amp for dual zones i.e. four speakers). This would give nice coverage without a big investment, and keep the subs out of the way. The questions now is would four be too many or cause interference with each other, and what size of subs to go with?

The amp could probably power 4 - 12" subs with out any problem but I think that many big subs might be a problem and drowned out the rest of the movie powered only by the receiver. Her husband is likely to turn the amp all the way up when he is alone and not quite get it why it starts sounding crappy. (good guy but not always the swiftest) In a room that size and shape would 4 - 8" woofers put out enough low end though or should I go with tens? The reason I ask is partly for the budget, I have 4 - 8" cerwin vegas already.

Any thoughts?

[Mike P.]

If you want decent low end output in a space that size, four 8 inch Cerwin Vega's aren't going to do it. I can understand using the bottom cabinet of the four towers to make separate subs, I can't understand how 4 subs will be powered by one Audio Source 300 watt amp. Depending on the "ohms" of the subs viocecoils, chances are the final load is not going to be compatible with the amp. Making any recommondation would be a lot easier if you could tell us how much your budget is.

[Tiny]

The audio source amp used to power 4 - 4 ohm floor speakers each had 2 12" 4- 6" midranges and 2 big horn tweeters. It powered them well at all volume levels too.

Audio Source Amp 300 those are the amp specs.

I plan to run the receiver's sub out to the amplifier's main line-in. using a standard RCA Y cable.

The sub separates are all unpowered units at either 8 or 4 ohm depending on which speakers I end up with, which shouldn't be a problem for a 2 ohm amp. I have tested it down that low and you can really crank it without clipping. This is one of those really good amps that just doesn't get the credit it deserves. The subs will all be fed out through the standard speaker terminals with banana plugs on both ends of the cable. This setup won't give the power that 4 separate independent powered subs will, but it doesn't have to either, not to mention I can't run anything powered on the back wall so those would be out anyway.

I am in a budget of less than $200 for all four subs combined. The rest of the speakers are all pioneer based units with cerwin crossovers.

[tonyvdb]

The amp is rated to do a 2 ohm load stable but I wouldn't want to use it for running all 4 subs. The amount of power required to get any decent level out of the 4 subs will overheat that amp. If you place the existing JVC sub in one of the two front corners you will get a substantial improvement if thats not already the placement location.
Building the subs into the tower speakers will work but you must be aware that this is not ideal as the two may cause problems if not tuned properly. (frequency overlaps and harmonics issues given the fact that they are not matched speaker drivers).

[Mike P.]

$200 for 4 subs is doable. I'd recommend 4 - EHQS 12 inch subs in single 2 ohm version.

http://www.edesignaudio.com/edv2/pro...roducts_id=183

2 subs wired to 4 ohms for each channel of the Audio Source 300 watt amp. The plans for the sub boxes are here.

http://www.icixsound.com/vb/showthread.php?t=39744

The driver, port and MDF should be around $50 each. Don't forget to line the walls of the sub with egg crate foam which you can get at Walmart as a "mattress pad". It comes in different thicknesses. The 1.5 inch thickness is good enough.

[Tiny]

The current JVC sub is the corner and still not getting the job done. I have even tried running two 10" jbl subs with different placement and it still has far to many acoustic problems because of the shape of the room and the floor. Even after putting in a 12x16 rug in front of the couch and another one behind it the floor is horrible for sound so I need to either really blast the front out of the subs from the front or I am going to have to put in 4 subs. We tried it with 4 front firing subs pointed towards the center powered by that amp. That arrangement provided far better coverage than using 2 larger subs in the front running on the same amp. The problem was when we tried that all we had were six crappy unpowered subs to test. (My spl meter if it gave text message would have given me a you got to be kidding message)

One 15" pioneer down firing sub in the corner was our best test piece so far. In the corner it worked pretty well for movies but fell far short of what it is capable of. It sounded much better in the middle of the room but that was ruled out as it was another piece of furniture in the middle of the room. Giving them that sub was also ruled out by my wife, she is rather fond of it. She has it squirreled away with my pair of thrift store thiels in her office.

Back to the current problems for this setup. Do you think that the amp would power 2 - 12" pioneer subs sufficiently in the front. If I do that I can run with all pioneer speakers including unpowered 12" woofers in the rear towers for a more unified sound field. This wouldn't give quite the coverage we were looking for, but it is in budget and has expandability options down the road by adding another amp. This situation only works if the current amp is going to be enough to power 2 subs in the front towers. Any thoughts on that?

Also for stability and vibration control in the towers I was thinking of lining the floor of each with either concrete or sand. Speaker spikes would be nice, but not going to work on this floor.

[Mike P.]

The amp would esily power the 4 - EHQS 12 subs that I mentioned. To know if the amp will power 12 inch Pioneer subs, we would need to know the model number you're considering to see what the capabilities are.

[Warmon]

Just throwing out another option - he could get 2 Mach5 MJ-18's for $218 shipped.

[Tiny]

I could build one nice sub with the 18" and 1000w plate amp I already have but it comes back to it being a separate piece of furniture and because of the acoustics in the room have to be centrally placed for complete coverage.

[Warmon]

That's 2 - as in two 18's for $218 shipped. That 1000 watt amp would be perfect. What do you have for corners? Do you have room for two 8cf EBS boxes there? Otherwise, I think you had the right idea with the coffee table sub - except maybe trying to float a down-fired design.

[Tiny]

That does open up possibilities. As much as I think the coffee table would be best there is a mobility issue for the sister in law. She has to use a crutch after a car accident and anything in the middle of the floor is a bad idea. If I really wanted to make a coffee table sub though a friend of mine has a custom 24" cerwin vega sitting in his shop.

[Warmon]

Have you given any consideration to an IB setup? That would get everything off the floor. There is a good IB forum here with project pics to give you some ideas.

[javrt]

It's better only one sub than more. If you use more than one you've got frequencyes canceled in some zones of your room.The best option is to place one sub connected to your amplifier and move around your room with somebody seated in your listening zone a nd you notice where is the best position when you find it.

[BoomieMCT]

javrt wrote:

It's better only one sub than more. If you use more than one you've got frequencyes canceled in some zones of your room.The best option is to place one sub connected to your amplifier and move around your room with somebody seated in your listening zone a nd you notice where is the best position when you find it.

Although that is the conventional wisdom in my HT I got much flatter response and larger sweet spots using two subs placed at the 1/3 parts across the front wall. My HT (a 1800 cubic foot sealed room) had some pretty bad room modes that I couldn't completely fix with treatments. Careful placement of two subs were able to (mostly) remove them.

[thxgoon]

Ya generally speaking multiple well placed subs will smooth response in the room as a whole. Don't forget though, that other than smoothing response multiple subs will not produce more output unless they are in the same place. If they are in the same place 2 subs will be 3db louder than 1 and 4 3db louder than 2. So your four subs will be only 6 db louder than 1 if and only if they are excursion limited. In other words, if your amp can't drive all four to their excursion limits you are not going to gain output from additional subs. Output is a function of power. My advice would be to look for a high sensitivity driver and port the boxes to gain the most output. Good luck and let us know!

Any chance of a ceiling mounted IB for those 18's?

[Tiny]

On advice from a couple of people I am going with 4 EHQS12, it will make my cabinets a little taller than I wanted but such is life. I am doubling them up in the front as suggested using the audio source amp. The surround cabinets will be the same size and shape so I can add more subs to those lower cabinets in the future if they get another amp and desire it. Hey who knows what santa will bring them next christmas.

My question now becomes feet for the speakers since speaker spikes are out. Does anyone have rubber feet recommendations? Secondly Secondly each cabinet will weigh in between 45 and 50 pounds without speakers. I want to weight down each tower some more, I am thinking bags of play sand any thoughts? I really want these speakers to stay where i put them. Part of the reason will be to keep my brother in law from moving them with anything short of a dolly, which should pretty much rule out him ever moving them since that is way too much work for him. Instead of sand I actually thought about coating the outside of the cabinet in concrete then adobe to go with the southwest feel of the rugs and other objects in the room.

[toecheese]

BoomieMCT wrote:

Although that is the conventional wisdom in my HT I got much flatter response and larger sweet spots using two subs placed at the 1/3 parts across the front wall. My HT (a 1800 cubic foot sealed room) had some pretty bad room modes that I couldn't completely fix with treatments. Careful placement of two subs were able to (mostly) remove them.

I still think conventional wisdom would win overall- for every 'sweet spot' you create, there will be an arc of nulls from multiple low-frequency sources.

The reason we have front/center/surrounds/back surrounds is for directional imaging of sound. We know where the sound comes from and it isn't (just) for sound pressure, but for this soundstage (two fronts can create a sound between them, etc.).

Subwoofers are not this animal- they are meant to be low frequency and non-directional, so a single source is all that matters. It should be centered and towards the front of the room. Anything you do past this introduces multiple variables, including that of heisenberg uncertainty (not in the quantum sense, but that a second sub affects the measurements of the first).

I'm a huge fan of (ha, non-(rotary)-fan) IB subwoofers because of their theoretical superiority in producing clean bass. It gives you the ability have a HUGE subwoofer, without a huge box centered in the middle of the room.

[Tiny]

toecheese wrote:

I still think conventional wisdom would win overall- for every 'sweet spot' you create, there will be an arc of nulls from multiple low-frequency sources.

So long as the listen/viewing area is in the sweet spot, the null arcs don't matter.

toecheese wrote:

Subwoofers are not this animal- they are meant to be low frequency and non-directional, so a single source is all that matters. It should be centered and towards the front of the room. Anything you do past this introduces multiple variables, including that of heisenberg uncertainty (not in the quantum sense, but that a second sub affects the measurements of the first).

Correct in theory subs are supposed to be low frequency non directional monsters, however room dynamics are always going to screw with that. This room will never support a single sub in one corner and other requirements allow them to be placed nowhere but along the wall. If the world was perfect we would all own Thiels powered by McIntosh and have closed theater rooms separate from out closed music rooms.

[toecheese]

Tiny wrote:

So long as the listen/viewing area is in the sweet spot, the null arcs don't matter.

Correct in theory subs are supposed to be low frequency non directional monsters, however room dynamics are always going to screw with that. This room will never support a single sub in one corner and other requirements allow them to be placed nowhere but along the wall. .

Guess it depends on how selfish you are. I've got 7 seats in my HT... Sacrificing one sweet spot for a bunch of additional nulls and hotspots doesn't add up. That being said *my* chair is perfect

I didn't pay much attention to your room dynamics, but was responding to the title of the thread, which was 'how many subs is too many'- and my answer is anything more than one is too many. YMMV.

If your question is how many drivers, then you can't have enough

Edit: I've gone back and read about your room, and it really isn't a room at all, but an open area. You won't be able to fill it properly ( I have a similar situation with my living 'room') and I just got the biggest speakers for my mains and threw in an el-cheapo sub in the corner and acknowledge that I can't really do anything to make it better.