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oliverstoned wrote: Catcher10 wrote: Thanks Dean....totally makes sense. But is it then my mind playing tricks on me, when I actually see the sub under a table or next to a setup (like in Olivers case)...that I can tell where the low end is coming from and if I move around it seems to "disappear", the sound that is. I have my Bose sub tucked behind a sofa at least 4.5m away from the small cube speakers.....I guess our ears can play tricks on us...... IMO a real sub is 38 cm diameter. Below, it just makes "boom boom".

oliverstoned wrote: It doesn't sounds stupid on the paper but i recently moved my system to the living room but just before it was in a less than 30m2 room with low ceiling and full of furnitures and it wasn't sounding unpleasant at all...I think each room has its acoustic, some rooms stand the extreme low, others don't.

Obviously there is more to room acoustics than just size and I did mention sound absorbing vs. sound reflecting surfaces (ie the amount of soft and hard furniture in the room). Position is also important, a sub in a corner is going to reflect off 3 room surfaces whereas one placed in the middle of a wall will only reflect off two; and one place behind furniture/equipment rack will be absorbed/reflected differently to one in front that has no obstructions. However room size is the defining parameter - a small room will have a small volume of air to move, and a big sub will want to move more air than the room contains - this can dampen the dynamics of the speaker (something that constructors of sealed speaker & infinite baffle speaker cabinets know all about) - the rooms natural reasonance has a lot to do with how a sub will sound so matching the sub to the room is as important as matching the speaker cabinet to the speaker itself. While your sub didn't sound unpleasant in a small room, I suspect it would have sounded better with a smaller diameter driver, or in a bigger room, but if you are happy with the sound then that is the be all and end all of of it.  

Edited by Dean - September 18 2011 at 04:58

 okay... yes it will sort of do that... the weight of the rock puts the sidewalls of the cabinet under tension, which only serves to move the resonance higher up the frequency spectrum, it will also create a sub-sonic pendulum type effect (stick with a weight on the end) which may not be such a good idea. But, again - if it works for you then that's fine. Frankly I'm surprised that the sub needed such drastic (and brutal) treatment - those design guys at Magnat should be able to design a cab that doesn't rattle.

oliverstoned wrote: Some audiophiles even put some hydraulic jacks on all sides of their subs... It not only works for me but for everybody: if you don't do that, the low dribbles. The effect is huge. Anyway, it's not the fault of engineers but money and weight contraints. Including a 100lbs plate would have a cost in freight as well. If you want your sub to work fully, you have to add weight or find another way, that's why optimization is necessary.

Edited by Dean - September 19 2011 at 10:07

Catcher10 wrote: If the sub is designed to move so much air mass, even with my tiny Bose sub I have blown out a candle flame...

Catcher10 wrote: ...I wondered if putting your sub almost directly behind your bookshelf speaker (as in oliverstoned setup), would add unwanted vibration or movement? Is this possible?

Dean wrote: Frankly I'm surprised that the sub needed such drastic (and brutal) treatment

I don't listen to theories and formulas but to sound. You'd be surprised by the gap between your theories and experience.

My hifi guru (the guy who learned me all i know thanks to his 40 years of experience)is himself an engineer from the famous Poytechnique school and from the first day he told me that engineers were
painful because they think they know everything whereas this knowledge is only theorical.


Edited by oliverstoned - September 20 2011 at 03:27

Catcher10 wrote: If the sub is designed to move so much air mass, even with my tiny Bose sub I have blown out a candle flame......I wondered if putting your sub almost directly behind your bookshelf speaker (as in oliverstoned setup), would add unwanted vibration or movement? Is this possible?

Of course the sub produces its own vibrations which may affect the rack of electronics if close. Putting heavy weight also lower the unwanted vibrations produced by the sub, a second effect of that upgrade.
Rather than smoky theories and formulas, the best is to try and listen.
Because we don't listen to theories but to sound.

So why are you so categoric in your speech?

I don't ignore theories, i simply don't care about it.
Only the result counts for me. And if i'd follow your theories, my system would be an ordinary badly sounding one.



Edited by oliverstoned - September 20 2011 at 04:33

oliverstoned wrote: So why are you so categoric in your speech?

I cannot say that I have been, certainly less so than yours at least.

Dean wrote: oliverstoned wrote: So why are you so categoric in your speech? I cannot say that I have been, certainly less so than yours at least.

No because i'm experienced and you're not. You're experienced with theories only.