I like my amp sound better "off axis"

[ErikH]

Re: I like my amp sound better "off axis"

This happens because you are not directly in the center of the cone, which is where the harsh frequencies project from. The further out from the center you move, the softer the frequencies get. What you're experiencing is exactly the same thing as putting a mic in front of the speaker.

 

[Rich_S]

Re: I like my amp sound better "off axis"

When I last saw Lynch, he was playing some old school Marshall Super Leads, or whatever, but they were non-master volumes I think. Anyway, it was a very small venue, and he had his amps pointed BACKWARDS (that's why I'm not sure of the models). Probably did it to avoid killing everyone in the front row. Didn't care for his tone that night... on-axis I bet.

Back in the seventies, everybody that played in the South Jersey bars did that. There weren't any JCM800's yet, and face it: even a 50-watt non-master halfstack is WAY overkill for a bar. So everybody would point their cab at the back wall, mike it, and cover the whole mess with blankets or coats or whatever. Kind of an improvised isolation cab. At least they could crank their Marshall up to the sweet spot. I once saw a guy in a big bar (ex-supermarket building, very high ceiling) lay his cab on its back, pointed straight up, then mike it.

But this is off topic - these guys did this for volume-control purposes, not on/off-axis tonal differences.

 

[Rich_S]

Re: I like my amp sound better "off axis"

Back on-topic:

A speaker's "spread" is based largely on the relationship of the wave length to it's diameter. From this, a couple of logical extensions:

1) High frequencies tend to stay concentrated in the center but fall off to the sides.

2) All else being equal, a larger speaker will be "beamier" than a smaller speaker (this is why I was kinda surprised to see SRV with duct tape on a 4-10 combo).

As an aside, sealed-back cabs exaggerate all of this, since they don't spread the sound around the way open-back combos do.

So, if you prefer your off-axis sound to on-axis, there are several remedies:

a) Stand off-axis: This will make it sound great to you, but is someone else getting killed with the louder, shriller on-axis sound? You're likely to turn the amp up to get your sweet off-axis tone loud enough. Whether or not someone is standing right in the line of fire, that center axis is the loudest part of your sound, and it's going somewhere. At the very leasy, it's bouncing around in the room, raising the overall volume while reducing definition and intelligibility. (Of course, when the whole room gets cluttered up with unintelligible noise, everyone else is going to turn up so that they can hear themselves.)

b) Add Beam-Blockers (or duct tape): This will kill some of the highs in the on-axis area, making the response more consistent across the stage. You'll hear something similar no matter where you stand, and so will everyone else.

c) Replace your speakers with something that has an on-axis sound you like: (IMO, the best option). This way, you can point your cab right at yourself, and hear a tone you like. Since you are now standing in the loudest part of the pattern, you're happy because everyone likes to be the loudest. The rest of your amp's distribution pattern is quieter than where you're standing, which means less of you for the other band members, less chance of killing someone who paid top $$$ for front-row seats with less-than-stellar tone, and less useless volume cluttering up the overall sound in the room (and less chance of the soundman getting bitchy with you).

 

[jimpmiller]

Re: I like my amp sound better "off axis"

so the duct tape..like on the tolex cloth of the amp? or do you take the cover off and put it right on the speaker?

 

[Rich_S]

Re: I like my amp sound better "off axis"

so the duct tape..like on the tolex cloth of the amp? or do you take the cover off and put it right on the speaker?

Tolex is the vinyl covering on the amp. The duct tape goes on the grill cloth - the fabric covering in front of the speakers. Just a small square of tape right in the middle of each speaker should do it. Check out SRV's Super Reverb (?) in the El Mocambo video, and you'll see them.

The Weber BeamBlocker is a bit more elegant - it goes behind the grill cloth so it's nearly invisible. It has long skinny arms that span the speaker cutout for support - I assume it sandwiches between the baffle board and the speaker frame, on an opposing pair of speaker mounting bolts.

 

[ErikH]

Re: I like my amp sound better "off axis"

Tolex is the vinyl covering on the amp. The duct tape goes on the grill cloth - the fabric covering in front of the speakers. Just a small square of tape right in the middle of each speaker should do it. Check out SRV's Super Reverb (?) in the El Mocambo video, and you'll see them.

The Weber BeamBlocker is a bit more elegant - it goes behind the grill cloth so it's nearly invisible. It has long skinny arms that span the speaker cutout for support - I assume it sandwiches between the baffle board and the speaker frame, on an opposing pair of speaker mounting bolts.

That's exactly what it does, Rich. Just undo the opposing screws, slap it on and put the screws back in. That's an easy DIY job right there. And if you want to just use tape on the grill, put it on the back of grill so it's not seen. I may do that to mind since my grill comes off the front. Some grills you have to undo some screws from the inside which requires removing the back, like Marshalls.

 

[ratherdashing]

Re: I like my amp sound better "off axis"

The Weber Beam Blocker is essentially the same thing you will find on some studio monitor tweeters, scaled up to fit on a 12". Observe:

http://www.samsontech.com/products/relatedDocs/Resolv65a-pair.jpg

 

[Rich_S]

Re: I like my amp sound better "off axis"

I just got the new (McCartney) Guitar Player. There's an add for the new Jekyl & Hyde combo amps. Instead of fabric grills, they have chrome rings designed to look like mag wheels, with a blocker incorporated into the center.

 

[ErikH]

Re: I like my amp sound better "off axis"

I just got the new (McCartney) Guitar Player. There's an add for the new Jekyl & Hyde combo amps. Instead of fabric grills, they have chrome rings designed to look like mag wheels, with a blocker incorporated into the center.

If they're the ones I'm thinking they are, I know the guy that designed the amp. He's a hell of a nice guy and knows electronics like the back of his hand.