Beam Blockers

[angelodp]

Any of you guys use this device in your amps..... beam blocker.

ange

[Sonny ReVerb]

Search is your friend...

Check this post out:

http://ampgarage.com/forum/viewtopic.php?p=83201#83201

[Kregg]

Beam blockers do work, but, they aren't always necessary. The problem with so many guitarists is that they tend not to roll the tone down when overdriving a signal. You could also EQ your rig to keep some frequencies from getting too unruly. All to often wah-wahs tend to jump over the high pitch edge; which is not at all pleasing. When playing live get your mix right.

I have yet to see a high end hifi setup with beam blockers. In fact hifi aficionados love their ears, want them to last, and prefer to hear tone (timbre) and nuance rather than high volume.
The point being, either get better speakers, or stop aiming high volume pitchy sounds with the speaker centered at head level.

[Structo]

Kregg did you happen to read that Gear Page thread about the use of the foam doughnuts?

Jay Mitchell that wrote it does a pretty good job of explaining how it works.

He claims the high frequency ice pick tones do not just come from the center of the speaker but throughout the surface of the cone.

That is why he says that the typical beam blocker that covers the center of the cone does not work well.

His foam idea, makes the speaker sound the same whether you are on axis or off axis.

I read that whole damn thread one day.
I came to the conclusion that it worked for more guys that it did not.

The guys that tilted back there speaker cabs so the sound is aimed at their ears were the ones that saw the greatest improvement of reducing the on axis ice pick tone.

[ampdoc1]

I designed and sold the Speaker Tweaker device back in the early 90's. It was a series of concentric rings around a ~2" solid center. It worked more on the principal of a window shade party opened. It blocked some of the direct output loudness while reflecting high frequencies in an omnidirectional pattern.

It wasn't for everybody's taste, but the players that liked it reported the results were good,...the signal was not as harsh, and the output was very balanced in loudness almost 180 degrees in front of the amp.

ampdoc1

[Rimy]

i've had the beamblockers installed in all of my amps for the last 5 years and i liked it untill now.
as i read the thread at the gear page i thought i give it a try with the foam which costs only a few cent. the difference is amazing. you've got allmost an 180° angle where the sound is the same as in the center.
with the beam blockers there was less treble and the definition of tone was not the same. with the foam you can move your ear around in front of the speaker with allmost no difference. on the other side with the beam blockers there was right in the center allmost no treb at all and as you move your ear there were some dead spots where there was a sort of phase cancelling in the upper mid and treble.
now all these dead spots are gone and the sound is well ballanced everywhere infront of the amp.

ralph

[tubeswell]

Beam blockers are really finnikity to set up right. If the blockers are too big or the wrong shape/ wrong density/material etc they can really rob your sound of balance and completely knock out the high end. You don't need anything very big to eliminate the ice-pick. I have tried a variety of blockers with some of my past amps and now I don't bother with them at all. I just use good quality speakers that are not too over-rated powerwise for the amp, and that seems to work better (for me).

I have heard some peeps have been pleased with a small bit of polystyrene tacked onto the inside of the grille cloth with a small dab of hot glue. Altho' I haven't tried this particular configuration myself, if probably has some merit.

[Andy Le Blanc]

Ya ..... get a few styro-foam balls of different sizes and cut off various diameter
slices and pin them to the inside of your grill cloth above the speaker center.
Its fun to play with. Or better yet, just slightly roll off the volume on your
guitar.

[Kregg]

Structo, the foam donut thread was certainly interesting. A couple of questions arose as I read through Jay's thread. Don't we already do that to some extent by our choice of grill cloth? When I add speaker grills to my reference speakers clarity and coloration are noticeably different. Then again I'm not overdriving the speakers.
Second, why use a donut; when a solid sheet of open cell foam would do the same thing? If the foam donut crowd wants to test my theory, all they have to do is tape open cell foam to the front of their speaker cabinet.

[greiswig]

(SNIP)Second, why use a donut; when a solid sheet of open cell foam would do the same thing? If the foam donut crowd wants to test my theory, all they have to do is tape open cell foam to the front of their speaker cabinet.

Here's my guess: if you don't have the hole in it, you're effectively creating resistance to the cone movement because of the restricted airflow. It'll just move the foam if you have a grillcloth, but I'd guess that would present its own issues.

[Kregg]

That's as good an explanation as any. I could see how that might be a minor issue with closed back cabinets, for that matter one could punch holes in random locations around the foam.

[Structo]

Jay was pretty adamant about the 3 inch hole dead center of the speaker.

I was kind of an amusing thread when some guys would say, oh I just cut a 2 inch hole or some other alteration rather than sticking with the known facts that Jay has discovered.
He apparently manufactures high end speakers or works for a company that does.
Then of course the naysayers that couldn't accept something so simple working well as it apparently does.
One guy in particular was very argumentative with Jay.

But what was an eye opener for me was the fact that the high frequencies don't come from the center of the speaker as a lot of us have thought forever.
What he said makes perfect sense and eventually I will give it a try.

The biggest problem seems to be sourcing the correct firmness of foam.

Also, if your grill cloth is too close to the speaker and touches the surround, it can have detrimental effects.

It must not touch the speaker, and the hole in the doughnut must be dead center to the dust cap.

The McMaster foam mentioned in the thread is close and near the end of the thread there was another source mentioned that might be the ticket.
Jays company buys the foam he uses in bulk and he was a bit secretive about the exact foam he uses.

I'm not playing out currently so this is a non issue for me right now.

My 2x12 cab is sitting on the floor so bass reinforcement is more of an issue than the treble is for me.....


The frequent comments that were encouraging were the comments from the other band members in the group that said, hey, my ears aren't bleeding anymore and similar comments from people that were on axis to the speakers.

Not too big of an investment to give it a try.

[jaysg]

During the last BB thread at TGP, it occurred to me that most of the players who didn't like them were using 4-12" cabinets. I have a few in single speaker boxes and I'm a happy camper. It seems reasonable that various approaches might have different results in 2x, 3x, and 4x cabinets where there are interesting node/anti-node patterns before blocking.

[Alexo]

My 2x12 cab is sitting on the floor so bass reinforcement is more of an issue than the treble is for me.....

Ta-da...

http://www.sweetwater.com/store/detail/GRAMMA/

[Structo]

Thanks I have seen those before.