Foam under my monitors: Useful?

[estevan carlos benson]

I have a couple of generic monitors sitting on top of my makeshift door/table. I'm getting an extremely false bass response I know is related to the monitors and table. There are probably several solutions such as foam. Would it be that useful? Any other suggestions?

I'm using M-Audio Studiophile AV 40 (http://www.m-audio.com/products/en_us/S ... eAV40.html). I just want to get as accurate a sound from these generic monitors as possible.

[agent314]

A little rubber underneath them goes a long way.

Also, do you have the little 'bass boost' switch set to On on the back?

[Kent_in_CO]

Absolutely foam will help. Get these ASAP and you'll be good to go, as far as vibration-isolation is concerned.

http://accessories.musiciansfriend.com/ ... sku=422603


Kent // SEVEN7H WAVE // www.seven7hwave.com

[Tone Deft]

the idea is that you want them coupled tight to a solid surface or floating in the air so the surface they're on doesn't affect them. anything in between puts imperfections in the frequency response.

floating the monitors makes for less bass (but a flatter freq response), so turn the bass up.

so, there's audio, pressure waves in the air hitting your ear. these waves are made by the speaker's cone pushing against the air. the cone is pushed by the coil which is supported by the speaker's housing. the housing sits on your desk's flat surface. if that surface can move, that movement will affect how well all of the coil's energy is transferred to the speaker cone.

first night I had my Adams I listened to tunes and they sounded like crap. I put some Auralex foam under them and it made a world of difference.

or maybe you need to go the solid way. leave them alone or put a heavy brick under them to weigh down the surface.

it's all about efficient, predictable, consistent energy transfer.

hth...

[Angstrom]

that isolation foam helps, but what might help even more is trying some alternative placings of your monitors/setup in relation to the room you are in.

Most Bass issues come from the room resonances. You are decoupling the monitor from the resonator(the room) by isolating it from the easiest transmission path (table->floor), but as the emitted audio wave bounces around your room it will set up some nasty resonances as it folds back on itself. there will be peaks and troughs.

As a cheap and quick experiment you can try using a sine wave sweeping slowly down from 10,000Hz to 20Hz and you should quite easily hear where the volume appears to jump up and down.

The best solution/option is obtaining some big-assed bass traps, but as I said - if you can: try moving your gear around so that the nodal problems are at least minimised. That's the cheapest (part of any) solution.

[southsounder]

I second trying a different location.

I've got a pair of little JBL Monitor One's sitting on my desk that I use for secondary reference. Even with Auralex Mopads to decouple them from the tabletop they're still way boomier than my big KRK9000's, which are set up on proper stands away from the table.

I also noticed that when I temporarily raised one of the JBL's up farther from the table top it made a world of difference as far as the excessive bass response.

Before you try anything else, get your speakers up off the tabletop and closer to ear level. I think you'll be surprised how much difference it makes.

And for the record, on my KRK's I swapped out the Mopads in favor of those butt heavy Primacoustic Recoil Pad things. To my ears they do make a significant difference.

[leedsquietman]

http://www.zzounds.com/item--PRIRECOILRX5

these make a very tangible difference to a lot of monitors. Pricy - but good.

[Spectrumdisco]

Its amazing how much even a bit of repositioning can affect the sound

[Forge.]

Is the door solid? If not I would sack it. Actually I recommend speaker stands they're not that dear

[boogaloo]

Honestly, I wouldn't expect much in the way of an accurate bass response from those monitors with their 4 inch woofer. That's not to say that you shouldn't try the advice you've been given but at least invest in a pair of proper monitors if you can afford it.

[dancerchris]

I would recommend against foam under a speaker. As Tone says it is about energy transfer. Foam can actually absorb energy like a shock absorber (mechanically it is a dampener). It can be used as a quick solution to vibration issues when you have poor placement on something weak mechanically, e.g. to eliminate rattles and the like. But it will lead to reduced bass response. The best way to enhance bass response is room treatment. The best way to enhance mechanical coupling is to secure the cabininet to something solid. Audiophiles use spikes to solidly connect their cabinets to carpetted floors. Also increasing the cabinet weight is another way to enhance coupling. I think placing sand bags on top is a good way of doing that. In fact sand bags underneath would probably be better than foam for enhanced coupling to the surface. Don't be fooled by acoustic foam manufacturers' claims.

My $0.02

[Angstrom]

HUH?
is it really right that you want to couple the driver to the room?
I'm not really sure how that could be good, I think de-coupling is the best way to eliminate non-designed resonances.

My understanding of the "large heavy block" methodology was to kill the transmission with an overload of mass, not to felicitate the transmission (through rigidity).
If you think about it : if your intent was to connect the driver to the room then lightweight rigidity would be the method, mass kills vibration. The cone already has a designed resonator, and it's usually bolted into that.

I'm really of the opinion that the driver and its tuned enclosure is meant to be separated physically from the surrounding room, leaving only the air mass moving as the designer intended.

I'm no room design expert, but this is how I understand it.

[leedsquietman]

The reason I recommended the Primacoustic Recoil pads is that they weigh 12 lbs each and work are a combination of steel and foam and work very well for most monitors. Auralex Mopads also make a difference but not as dramatic but are cheaper.

With no disrespect, if you don't want to take my word for it, you can take the word of top producers and engineers such as Daniel Lanois, Bruce Swedien (who mixed Michael Jackson's albums) etc
http://www.primacoustic.com/recoil-artists.htm

[Rave]

The reason I recommended the Primacoustic Recoil pads is that they weigh 12 lbs each and work are a combination of steel and foam and work very well for most monitors. Auralex Mopads also make a difference but not as dramatic but are cheaper.

With no disrespect, if you don't want to take my word for it, you can take the word of top producers and engineers such as Daniel Lanois, Bruce Swedien (who mixed Michael Jackson's albums) etc
http://www.primacoustic.com/recoil-artists.htm

I got prima pads, they rule and lots of people swear by them

[ze2be]

With no disrespect, if you don't want to take my word for it, you can take the word of top producers and engineers such as Daniel Lanois, Bruce Swedien (who mixed Michael Jackson's albums) etc
http://www.primacoustic.com/recoil-artists.htm

Man, that's a lot of positive feedback. I almost fell a sleep half way through.
Would it be worth it for a livingroom-corner setup? I just got some standard foam on the corner walls. Nearfields on the desk, on top of some of the same foam.