terrible bass response / unevenness problem.


im sure you all have experienced the problem i have here, but i need sugestions on how to tame the uneven bass response in my room, the bass in my room is just terrible. im already going to change subs from a 12" to a 10" sub. (room is 12 X 13)

the problem is mainly with the low bass frequencies, at cretain low frequencies, the level of the bass rises dramatically and resonates the whole room. terrible air shaking feeling. then as soon as the bass guitar in the music jumps up to a higher note, the sound is suddenly cleaner and the level goes back to normal. i want to find a way so that all frequencies are being heard at the same loudness,(and felt at the same intensity). the bass with my sub is also lacking any detail(integration problem?),. is dull and muffeled. i already tried moving my subwoofer from the front right corner of the room to the left front corner, which made a fairly significant improvement in the bass resonating/uneveness problem.

i was thinking of getting an equalizer, but im not sure of a good one to use for a home stereo setup. all the ones i see seem to be rack mount units. i know more bands are better, like 30 or so. i know they say that you should try to fix the problem another way, before going to an equalizer, but wouldnt an eq be cheaper than thousands of $$ worth of sound absorbant panels, bass traps, etc?.

ideas anyone??

chad
mainlymusicman
Sounds like your overloading the room.You didn't mention what gear your using in the room. If your going to use a sub..you should go sealed for sure.From what I've read, a digital eq might be your best bet with the room treaments..etc. You may have just too much low end response for the room your using. You could also change to a speaker where no sub is needed. One that has a smooth rolloff in the lower frequencies. I'm just throwing some ideas at you. Plenty of experimenting can be done.
Chances are, reducing the driver area from 12 to 10 will not cure this problem. I would begin by removing the sub from a corner, as this can make a big difference, and then reviewing the sub's manual to see what crossover points are available and how to apply them. I'd also get a SPL meter and a test disc so that you can see what the differences placement makes. Good luck.
Big rooms are bad enough. Small ones are much worse. Two rooms, 13x17x18 (drywall)and 24x17x9 (lathe and plaster) were where I gained my experience as I struggled with room/speaker combos that had 12+ db peaks: understand that right next to that resonant room frequency will always be "null" or suck out, making the actual note to note swing even worse.

With B&W 802 and 801, I had 18 db swings from one note to the next in the 80-100-120 htz. range. Genesis, with all their adjustments, were similar. Cls and "bass shy" Quads and Dynaudio monitors were the best. They lacked real bass, but the rooms helped them and they didn't muddy things up. As a musician adn bass player, that blew my mind. Lack of bass or muddy bass seemed to be the alternatives.

For years, I fought eq of any typ, esp digital, due to heavy investment in vinyl, TNT, SME V, VDH Black Beauty, Ensemble Phonobrio, etc. After 25+ years in "purist, high end", I bought a Tact EQ.

Even with AD conversion and "veils" on the sound, you have to be honest with yourself when you ask is transparency more important than reasonable IN ROOM REAL LIFE frequency response. Yes, BIG MONEY would let me build a better room, buy more bass traps than I've used before, more, tube traps, etc. but, for real life and affordable sound
(my system is over $50K worth, but after the fact room construction and treatment is very expensive), I'm always going to use something like this or a Rives.

Perhaps you could experiment for about $1500 or less with a Tact 2.0 with DA/AD converters and get rid of it if you didn't like it without too big a hit. It was less expensive than the ic cables connecting my pre to my power when I did it. I've since changed the ICs twice, but am convinced of the use of digital eq in normal/small rooms, probably even bigger ones.

Just my opinion.

JEff
thanks for the input guys. actually i just sold a monstrous 12" ported sub(HSU VTF-3)which went incredibly low and powerful, but thats actually not what i need. i need a tight fast bass response, with detail.. since my system is 90% music. and i think ill go with a james emb 1000 (sealed). i was using a sunfire stereo 300(older model) just sold that too. and probably going with a plinius 9200 integrated to drive my newly aquired Tyler Acoustics Linbrook signature monitors.. ill look into that eq.

thanks

chad
James makes good products, but I would also investigate REL. They are available at a good many hi-end shops as well as some Tweeter stores. I've heard the James and the RELs and prefer the latter.
A DSP processor with a digital notch filter for base control would probably help. My Anthem AVM-20 has this feature and it works very well....if you like vinyl then you can still do it.... just use the DAC to convert to digital and then apply the digital processing you require and finally convert back to analog.

Purists will of course sneer at this suggestion...but I assure you it works and digital signal filtering is sharper and better defined than analog. I find this unavoidable when using the sub and speakers to play stereo music together despite the reponse curves of my sub/speakers being engineered to be flat down to 30 Hz and -6db at 20Hz. These speaker specs are for ideal anechoic conditions and not for my room which reinforces a 40 Hz signal and hence a notch filter is unavoidable if you want to achieve a reasonably flat response in your base.

Another option is to move your sub away from both walls to say about 1/3 across the room and then shift it slightly off the diagonal room axis by a foot....good for your sound but probably bad for ergonomics and it wont completely cure the resonance but it will likely reduce it.
The dimensions of a room will cause low frequency modes (areas of reinforcement) and nodes (areas of cancellation). This is true of each dimension. The fact that two of your room dimensions are so close compounds the problem becuase you have these generated by both pairs of walls at almost the same frequencies. I used both ASC bass traps and a Rives PARC coupled with their BARE software to tame my room with excellent results. Granted, this is an expensive solution, but one is possible. Here are a couple of helpful links:
http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/waves/swf.html

and www.tubetrap.com
Shadorne - I agree. Speakers can be as flat as you like, but if your room isn't, your lost without correction, be it electrical, digital or mechanical/physical.

A flat response gives everyone a chance. What you do with it from there is up to you and your room!

I have MRC bult into my processor which acts like the Tact, you choose the ms decay time and it balances it out.