speaker placement, room treatment esp. floor ?

so i've sorta-kinda settled in to my new apartment, it's a 'loft' style place, considered a 1 bedroom, although i'd call it more of a glorified 'studio' because of it's open design.

anyhow, i'm struggling w/ the concrete floors, my old place was built in the 1800s and everything had a warmer, richer sound (part of it might be because i was closer to the speakers and the back wall?). anyway, what i see is, by math, the room is pretty decent, 13-14ish foot ceilings, 23x18, so no 'factor of' stuff going on... however, it's my guess that between the ceiling design (open LARGE wooden rafters), the concrete floor, the brick wall on one side and open wall on the other and irregular rear wall, well, lets just say i'm guessing it's all adding up to skew things.

my apartment layout - http://www.dmoffitt.net/apt/apt_layout.jpg

now. a few words before getting deeper into my questions:

my rig is 'good mid fi' or 'cheap / low-end hi-fi' at best. i'm a 24-year-old finishing my BFA degree in Film & Animation who got into hi-fi because of my love of movies. lately, HT has taken a back seat to 2chan. listening, ever since i purchased my CDM-1 NTs. now, i know they aren't the end-all-be-all, not even CLOSE, but upgrading from DM602 ser.1's to these, well, i'm happier. a friend has a pair of Totel Acoustic's Model 1 sig's and i'd say the B&Ws are about, oh, 80-90% of what those are, they don't extend as far down in the lower bass range, and the highs are still too bright/forward compared to the Totems (or 'better' B&Ws such as the 803/804).

anyhow, my rig in a nutshell:

Source: Apple G5 via AudioQuest OptiLink-1 digital optical cable (12m)
OR sometimes, Rotel RDV-1060 (for DVD-A / or sometimes redbook cd)
California Audio Labs Sigma (tube) DAC
Rotel RSX-1055 (using it as a Pre and to power my rear/surrounds)
Rotel RB-985 5ch amp (2ch each per fronts, last ch. is for the center)
all analog ICs are AudioQuest Coral (1m)
CDM1 NT connected via 2 runs AudioQuest CV-6 (Bi-Amp cfg)
CDMC NT center / DM600 ser.3 rear/surrounds (7.x setup)
Misc: StudioTech rack & stands (stands are filled w/ sand. they're CRAP tho, but i can't afford much more right now, hoping to find a sub-$300 upgrade). Panamax 5300 power conditioner, amp hooked straight to the wall to hospital grade outlet (audio rig is on it's own circuit in the breaker, thank god the apt. builders knew what they were doing!). Oh, and if it matters, a 32" Hitachi plasma (forgot the model, about 1-1.5 yrs old).

Back to business - so, for movies it's quite good, but as i've been told and guessed myself, that's the EASY part. could DEF. use a subwoofer, i'm hoping to audition an SPL 800, SPL 1000 and Digital Drive 10 (12?) in the near future, but i'm trying to optimize everything else to a reasonable extent before re-complicating stuff :)

But music, while extremely detailed, accurate, and with a VERY wide and fairly deep soundstage, lacks a LOT of bass, and the midrage could be a bit more forward or rather, like, warmer / more prevalant (which is funny to say, as the reviews I read years back of the CDM-1 said they midrange was a touch TOO forward, maybe it's my ears?). So what can I do to improve the low-end re: placement of the speakers, room treatment, furniture, etc? this afternoon I'm heading to home depot to snag a piece of 12x16 ft carpet to try and help things, i noticed a HUGE improvement just putting a 5x7 ft one between my listening position and the front / speakers, so I figured I'd see if I could further that (my guess is it cut down on the overwhelming reflections etc).

Also, with the concrete floors, do you think any of those subs will work or will the concrete make everything 'boomy' or peaky (hence considering the extra $$$ for the DD, being able to tune around room freq. problems)?

currently, everything is spiked directly to the floor (except, the rack's spikes are on brass 'cups' to help facilitate moving when/if necessary. the surrounds are hung on the wall (but as i said HT sounds fine).

I realize iv'e got a lot of areas that could use addressing re: equipment (i really want a good tube pre for 2ch, and a nice big 2ch amp like a b&k, classe, krell, etc) but right now, my budget allows only smaller occasional expenditures (except MAYBE the sub)... spending $90-150 on carpet vs $3-4000 for amplification, etc ;)

btw, to help picture the room / predicament better:

my apartment looking from the outer wall in (not my apt. actually, the neighbors, a mirror-image L-R of mine) - http://www.dmoffitt.net/apt/apt_looking_in.jpg

looking out from the kitchen area (again, not my apt.) - http://www.dmoffitt.net/apt/apt_looking_out.jpg

i've tried placing pro studio foam (same as we use @ RIT) in various places, to little/no improvement (either my ear is untrained or i've got bigger fish to fry, or, likely, both).

i do realize this will never have that jaw-dropping kind of sound that many of the rigs i've read about here have, but i'm VERY VERY happy with it, i just want some ideas / tweaks / direction before I start going and selling stuff a lot, spending money etc (ie. i want to get the most of what i have). my EVENTUAL plan is that this will become my films-only rig and i'm in the process of planning a 2ch only 2nd rig, but for now, budget, space, etc. dictates a 'hybrid' movie/music setup :(
As long as you're snagging some carpet, consider that natural fibers sound better than synthetic ones. I bought a HOme Depot area rug once, and it really didn't sound very good. This isn't a very scientific observation and I really can't explain why natural fibers sound smoother and warmer, but that's been my experience.

As you smooth out the midrange and treble reverberant energy in your room with the rug and/or other absorptive or diffusive objects, you'll probably improve the tonal balance somewhat. Of course moving the speakers closer to the room boundaries is the standard way of increasing bass - not sure how practical that will be, but thought I'd mention it.

Your listening position looks like it's essentially way out in the middle of a large open area. I bet you'd find the bass improved if you could move the listening position up against the rear wall, but that doesn't look possible. A subwoofer is probably the best way to restore the bottom octaves.

But for starters, try to find a natural-fiber rug.

Best of luck to you,

Rotel gear to me tends to sound a little "peaky" in the upper mids. I think that many people think that this sounds more "open" and "detailed", so Rotel may have voiced their gear this way on purpose.

On top of that and if i remember correctly, the RB-985 changes frequency response as drive levels are varied. At lower output, it was lean in presentation and began to level out as you pushed it harder. Given that you're using it with speakers that many consider to be a little bright in a huge room that you can't adequately pressurize, i don't doubt that the system lacks warmth and "oomph" at average listening levels.

Trying to treat such a room in terms of acoustics and leveling out the tonal balance can be a real handful. While it will be difficult to pressurize such a room due to sheer size, you really do need to work on filling in the bottom end. If i were in your shoes, i wouldn't hesitate to go for a subwoofer or two. This will at least help to balance things out a bit.

Until you can find suitable candidates that you think that you'll be happy with, i'm going to suggest something that many audiophiles will cringe over. That is, take advantage of your tone controls. Bringing up the bass response a tad and possibly softening the treble a bit may go a long ways for you. I don't know how effective or "transparent" the tone controls on your receiver are, but unless you are specifically sitting down doing "critical listening", i would much rather have "good sound" to enjoy around the house than cater to any pre-conceived audiophile notions. Besides, if you do use tone controls, it can be your own private secret. We won't kick you out of the club so long as you don't make a big deal out of it : ) Sean
Sean, you're quite right about the rotel 985, it is rather lean at lower gain, but fills in quite nicely as it increases.

i'm thinking a sub is the right thing, either a DD-10 (although i hear there are some reliability concerns) or SPL 1000 (800?).

btw - i tried what you suggested quite some time ago, and found that since the rsx-1055 merely has 'bass' and 'treble' that when i turn down treble and uped the gain a touch, or turned up 'bass' that the results were horrible. it tended to loose too much upper mid-range detail if i adjusted treble or it would make the bass boomier and the speakers 'honky' in the midrange if i increased the 'bass' setting. my CDM1's have often been called 'bright' (as many B&Ws are accused of being) but w/ the proper cabling (2 runs of CV-6, bi-amped) and enough power, i've managed to make the tweeter sound a bit more laid back and not as agressive/forward.

i haven't purchased a rug yet, i can't afford a nice wool / natural fiber one (in the 12x12 / 12x15 size i need, it would be well over $2000 and there's a lot of gear i'd rather have at that point even IF i could afford that much) so my next question is, if i get cheaper rug, similar to what you'd find on the floor of an office building (short pile / knotty / knobby stuff) should i put felt pad under it? also, should i put the speakers and rack on top of the carpet (spiked thru back to the concrete), or should i cut it shorter and have it start right in front of the speakers and extend to the listening area / under it?
got a pad-backed 12x15 piece of rug last night.

also got some better speaker stands (SC-14 from studiotech) and will be mass-loading them tonight...
Cut pile is better than loop for absorption and the types of padding each has a different coefficient of absorption.
well, got everything installed / set up last night. mass-loaded the stands w/ very small steel shot (20lb divided 5lb each among the 4 legs per stand) then sand on top (allowing the sand to filter down thru the shot as well), these things are BEASTS to move around, but it helped tighten up bass response a lot, and the overall stability is a billion times better (i used to worry about my old stands toppling, nothing will knock these over short of a cat-3+ huricane hehe).

the rug helped a LOT with reflections, the room was quite echo prone (if you clapped etc) and still needs to have some stuff addressed, i've got a number of accoustic treatment panels and corner pieces that i'm going to try moving around / experiment with this weekend). still NO bass, but i have a feeling that's my small-ish speakers in a big-ish room. gotta to try a sub at some point in the near future...