Speaker spikes/feet

[Buddster]

Brief back story.

Our band own and run our own PA. HK line array system, upto 8 bass units and 8 top units. They sound great, really portable and a small foot print. We've had this for about 10 years and done many, many gigs with them. Both ourselves and other bands at gigs. Myself and the drummer are both experienced sound engineers. 

However, we do occasionally get a lot of bottom end flare and can sound a bit wooly/undefined in the bass frequency. 

Of course it's very venue dependant, but my question to the collective is, does anyone use rubber feet/stand/spikes to de-couple the bass units from the floor, much the same as is used in hifi? This would seem to make sense, but I've never known it for PAs. The best sound we had recently was when we sat them in the little trollies we use for transportation. 

Anyone use or tried them? 

[LawrenceH]

Not used spikes, but when putting cabs on wooden stages or hollow floors with a propensity to resonate in the upper bass and low mids, I've had very good success using slabs of firm packing-type foam between the speakers and the floor. Audibly and measurably tightens up the bass in those scenarios - the kind of situation where you're otherwise pulling out tons somewhere between 80 and 300Hz on a graphic in an unsatisfactory attempt to control the woolly boom.

 

Edit to add it's also great under stage monitors and often buys more gain before feedback.

Edited yesterday at 00:24 by LawrenceH

[Bill Fitzmaurice]

Mechanical decoupling is an audiophile myth. What vibrates the stage is the acoustical output of the speaker, not mechanical coupling from the cabinet, which would be the tail wagging the dog. What can occur is that the vibrating stage will cause the cabinet to vibrate. The best way to prevent that is with a piece of yoga mat. More on the subject:  https://ethanwiner.com/speaker_isolation.htm

[Steve Browning]

5 hours ago, Bill Fitzmaurice said:

 More on the subject:  https://ethanwiner.com/speaker_isolation.htm

 

Fascinating reading. Thank you for that.

[LawrenceH]

In my experience yoga mat doesn't tend to work as well as foam slabs, it's not thick or firm enough to properly support the weight of heavy cabs through their feet so the decoupling is compromised. I've found foam blocks are much more reliably effective. The cab needs to be properly 'floating'.

 

Spikes can make a bit of a difference with hifi speakers, I suspect because they're placed in the corners of the cab where the panel vibrations tend to be reduced compared to the centre. That doesn't really apply in PA where cabs tend to have feet already.

 

 

[Bill Fitzmaurice]

Thicker foam of lower density can be beneficial on particularly soft stages. But too thick can result in the cab rocking. 

Spikes don't do anything useful from a sound standpoint. Where they can be beneficial is on a carpeted floor, gripping through the carpet to prevent speaker 'dancing' at high power levels, especially long-excursion subs. The quasi-magical properties attributed to them by some are just more audiophile piffle. 

[Dan Dare]

10 hours ago, Bill Fitzmaurice said:

Mechanical decoupling is an audiophile myth. What vibrates the stage is the acoustical output of the speaker, not mechanical coupling from the cabinet, which would be the tail wagging the dog. What can occur is that the vibrating stage will cause the cabinet to vibrate. The best way to prevent that is with a piece of yoga mat. More on the subject:  https://ethanwiner.com/speaker_isolation.htm

 

Good advice. To isolate my subs from floors and stages, I use semi-hard rubber tiles that I bought from a company that supplies them to schools, playgrounds and similar to place around swings and slides to prevent kids from injuring themselves if they fall. They're half a metre square, quite heavy and do a good job. The material is grippy, so cabs don't slide or move. Being intended for outdoor use, they're tough, too. Google "playground rubber tiles" and you'll find plenty.

Edited 14 hours ago by Dan Dare