Edited by bsoko2 - 12/11/12 at 12:53pm
Ashi - Hi. You’ve already received some good advice but I'll add my comments to add some more perspective for you. I currently run TWO SubMs in a room of about 1000 cu ft - IOW a very, very small room. I generally listen to movies fairly loud: -7dB on the MV. Now while my subs sound and measure really really well (you can see my detailed report a page or two back, with graphs) they do not in any way endanger my house!
My first thought is that you have not calibrated your system, or not calibrated properly anyway. Unless you have either a) measuring gear like REW or OmniMic, or Audyssey or Anti-Mode or similar, it is very difficult to calibrate subs. Using an SPL meter and setting the sub to 75dB is usually not very accurate, as the meters do not perform well down to 10Hz or less (unlike the SUbM). So my bet is that you just have the sub set up WAY too loud. My subs are set (on their own gain controls) to almost OFF for example - they are about two clicks from OFF*. How big is your listening room and how far do you sit from the speakers and/or sub? What equipment do you have? Do you have measuring gear, Audyssey, AntiMode etc? If you tell us what you have we can help you dial the sub in properly. Please see my detailed review for the procedure I had to do in order to get a nice flat response in my room. In the review you will see a remark about how I initially set the subs up (in excitement to hear them) and they did indeed shake the house. But the objective of a good sub is not to to shake and rattle your house. What level do you have the sub gain control set to?
Please answer the questions in red above and tell us more about your room, your system etc. A couple of photos would be useful too if you can (cellphone photos are fine). Don't worry - you will get this sorted with the help of this thread - but I bet if you could measure your response from 10Hz - 20kHz you would see a huge level boost from 30Hz down.
* Incidentally, setting the sub gain control very low doesn’t mean you are 'wasting' some of the sub as people sometimes think. It is a gain control not a volume control so what it does is control the incoming signal level that's all. Your sub will still deliver all of its power - just from a smaller input signal.
EQ isn’t the answer, although it's part of it (see my earlier reply). A system can be 100% properly EQd but if it is capable of playing a 10Hz tone at 115dB, it will still shake the house! I don't usually 'see' Gary J's posts but he is famous for posting a few words that usually don't help anyone much. If he really means that EQ will stop your subs shaking the house, he is just wrong (as you seemed to know intuitively). You do need to EQ the system to get the flattest response you can, but even if it is EQd you can still shake the house if it will play very loud, very low, which is just what a SubM can do.
It's true you don't necessarily need an EQ device or measuring gear but they do make the job so much easier. There aren't many (any?) big, powerful subs that don't benefit from a touch of EQ. Let's see what Ashi has got - he may have some measuring gear or EQ device already, in which case we can give him the heads-p on how to use it get a good flat response. But yeah, I agree - I'd bet they are just way too loud.
I think you'll find the bass IS dominating the other frequencies, but maybe you have always run your subs hot and are used to it. Thing is, you can run a lesser sub hot and it won't shake the house simply because it has very little capability below 20Hz. But the SubM is a beast and can really dig low, and go loud.
Where is the sub placed and where do you sit in relation to it? It is possible you are sitting in a huge null (20-30dB nulls are not uncommon). I know all about placement problems - goes with the territory for those of us with small rooms, but your room will be bigger than mine (I am sure!) and you’d be surprised how you actually do have placement options when your really try.
As you have already said the modes are horrible, how do you know? Have you calculated them with one of the many online room mode calulators, or have you measured? Like I say, sit in a 20-30dB null and you won't hear much bass - but the rest of the house will! Have you done a sub crawl or just tried moving around the room with an SPL meter and (while playing a bass test tone) seeing what the variation in SPL is at different parts of the room?
Hi Craig - there's no disagreeing with any of that at all, but I'll put my money on Ashi simply having it cranked up way too far - possibly because he's sitting in a null and doesn't realise it, or possibly because he has always overcooked his bass a lot with his previous sub which wasn't capable of bringing the house down. His symptoms are similar to the ones I had when I did a quick and dirty setup after the F2s arrived (impatience of course) and my whole house shook too. When I did a proper calibration later I realised that I was running the F2s about 10-12dB hot! And with Dynamic EQ adding Lord knows what to that as well! If Ashi can give us more info, and especially if has measuring capability, I am sure we can all help him dial in his sub properly.
It's fun to feel the house shake - but it gets old real fast and there's no substitution for proper, flat bass right across the frequency spectrum - something we have all had to do some work to achieve.
I think that when one gets to the level of Submersives, it takes (and rewards) some effort to get them working to their best - look at Mike Duke's story for example - and my own. And yours too of course. None of us just plonked the sub down where it would fit and then got a great result first time - we all had to work at it and I suspect Ashi will have to do the same. The joy is that, when the work is done, he will have bass like he has never had before - and not just in terms of quantity but even more important, in terms of quality.
Hi Craig - yes, I wasn't disagreeing with you - I was just adding my view that if Ashi is unknowingly running 15dB hot (maybe because he is sitting in a null) then he is sure to be shaking his house. If this is the case, chances are when he calibrates to a correct level, the shaking will go away. It's exactly what I found when doing the Q&D setup of my F2s.
EDIT: we are both definitely in agreement that EQ cannot fix sound transmission problems.
Wow! Ashi you do realise the numbers on the SubM are NEGATIVE values? The scale doesn't go from 1 to 36. It goes from -1 to -36. A setting of -7 is about 75% of full volume! My F2s, for example, are on something like -32. OK, I have two F2s and a small room, but even so I would say that you are running the SubM way, way, way too hot.