bass

[conbreaker]

Hello I am new to this forum jsut wondering about bass transmission and absorbtion. I have a home project studio i ran into a problem with bass i know it has somthing to do with standing waves when im up close to my monitors i hear lots of low end but as i get further away i hear less or none. why is that?

[phyl]

Home project studios are typically located in bedrooms or family rooms with relatively low (~8 foot) ceilings. The dimensions of these rooms tend to promote frequency response peaks and nulls in the lower end of the spectrum. This explains why you hear more/less bass as you walk around your room.

The most common treatment is to install low end absorption; you'll find references on this web site to panel traps, bass traps, low-mid absorbers, etc. All of these are meant to even out the frequency response of your room.

You can start to develop an understanding of how this all works by reading through the 'stickies' in each of the forums. You'll find formulas that predict where the problems in your room are, and if you're so inclined, test programs that generate tones which you then record and analyze in order to gather emperical evidence about your room.

Good luck.

[bpape]

So what does it sound like where you sit and listen? That's really the only position that matters. ALL rooms will have variations in bass response depending on where you are - even treated ones. IMO, the best thing to do is to get your seating in a position that promotes the smoothest response curve, set the speakers accordingly to that position, and then treat the room as described above with bass absorbtion of some kind (preferably some broadband at a minimum) to help control decay times and smooth the response even more.

If you have a choice of sitting in peaks or sitting in nulls, sit in the peaks - eay to deal with via parametric EQ. Nulls on the other hand are more difficult to deal with.

[Ethan Winer]

CB,

> as i get further away i hear less or none. why is that? <

The middle of the room, front to back, always has a huge null at a frequency set by the room's front-back dimension. Other deep nulls exist at predictable distances from the wall behind you. At a distance equal to 1/4 wavelength for a given frequency, there's a big null. 1/2 wavelength away there's a peak. 3/4 wavelength is a null again, and so forth. Other peaks and deep nulls exist all around the room due to distances from other walls. The smaller the room, the worst the response.

--Ethan

[conbreaker]

hi when I sit at the mixing location every thing sounds fine and even.

[Ethan Winer]

CB,

> when I sit at the mixing location every thing sounds fine and even. <

I doubt the low frequency response is even close to flat, but the only way you'll know for sure is to measure.

--Ethan

[bpape]

If it sounds good to you then you're probably in a decent position. This does not negate the need to measure it and provide some decay time control throughout the spectrum.

Helping smooth frequency response is only one of the benefits of absorbtion. A relatively smooth frequency response with a decay time 3-5x what it should be (not at all uncommon) is not giving you what your room/system is capable of.

Do you find yourself using EQ? Do you find that mixes sound one way in your room but when you listen somewhere else, it sounds different and you have to come back and compensate? Those are very common symptoms of a room that requires more control - especially in the bottom. Many of my customers that use bedrooms for mixing find that after treatment, their EQ requirments basically fall to almost zero.

What you may be hearing is a weak bass mix compensated for by room reinforcement. Or, a boomy mix compensated for by sitting in one or more nulls.