Of what importance is beaming anyway?

[maynardg]

Yesterday, I grew tired of a bit of shouty harshness in some passages coming from the tweeters on the Last Hurrahs. Tweeters are a good pair of LD25X over the 6.5" Seas U18. XO moved from 2500 up to about 2800. Harshness gone. Sound was good before, seems glorious now. However, the XO is clearly in the region where midrange beaming is supposed to potentially start being an issue. I have not measured off axis, but I can detect no fall off, or issues of any kind.

Just how important is beaming and under what circumstances could one be expected to hear the effects? What are the exacerbating or moderating factors in audibility?

[Melby Audio]

Re: Of what importance is beaming anyway?

My experience has been that is much more of an issue in full-range applications. A couple decibels down isn't going to be noticeable to most people. I doubt moving the crossover 300hz would make more than a decibel or two difference in you listening area. Full range, you can get painfully noticeable beaming.

[Sydney]

Re: Of what importance is beaming anyway?

...Just how important is beaming and under what circumstances could one be expected to hear the effects? What are the exacerbating or moderating factors in audibility?

Depends on who you talk to; to some constant uniform directivity is the goal.
Beaming infers there will be better listening positions than others.
If the goal was to put sound ONLY in a small pattern, than a beam is the goal.
( Such as Ultrasound devices that create directive sound from an aimed beam of ultrasound waves produced by a parametric array using heterodyning. )

[Jonathan Anspach]

Re: Of what importance is beaming anyway?

The problem isn't so much the beaming itself, but the transition from beaming just below the crossover frequency to very wide dispersion from the tweeter just above the crossover frequency. That can play havoc with imaging within that frequency range. It also causes a fairly abrupt change from "intimate" sound to spaciousness. Of course, the severity also depends on the characteristics of your listening room. A very live room will exacerbate the problem, and a very dead room will help hide it.

[Sydney]

Re: Of what importance is beaming anyway?

http://www.soundandcommunications.co...5_09_audio.htm

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Re: Of what importance is beaming anyway?

Yesterday, I grew tired of a bit of shouty harshness in some passages coming from the tweeters on the Last Hurrahs. Tweeters are a good pair of LD25X over the 6.5" Seas U18. XO moved from 2500 up to about 2800. Harshness gone. Sound was good before, seems glorious now. However, the XO is clearly in the region where midrange beaming is supposed to potentially start being an issue. I have not measured off axis, but I can detect no fall off, or issues of any kind.

Just how important is beaming and under what circumstances could one be expected to hear the effects? What are the exacerbating or moderating factors in audibility?

perhaps a crossover of just 2600 or 2675 would have alleviated the problem. That's when its nice to be able to measure distortion.

[Sydney]

Re: Of what importance is beaming anyway?

... XO moved from 2500 up to about 2800. Harshness gone. Sound was good before, seems glorious now. However, the XO is clearly in the region where midrange beaming is supposed to potentially start being an issue. ...circumstances could one be expected to hear the effects? What are the exacerbating or moderating factors in audibility?

Could not find crossover details via a search...
Passive? What Slope rate?

[maynardg]

Re: Of what importance is beaming anyway?

Passive, LR4.

[Paul Carmody]

Re: Of what importance is beaming anyway?

I think you may be walking into an "objective vs subjective" war. What I find interesting about PE board is that we have a pretty good mix of the two. Some boards (full range enthusiasts) live in subjective world. Whereas a board like HTguide leans much more to the objective side.

Personally, I think there's something to be learned from both camps.

[maynardg]

Re: Of what importance is beaming anyway?

Well, Paul, I am about to enter the single driver full range realm. A friend is giving me a pair of PS220-8 to try out. He has modified them quite extensively for others - to very good effect it is said. Will give them a try.

The Last Hurrahs really are very, very good. It turned out to be a good idea to build vented in a small box for the 8955A pair. Really tuneful, and the room gain seems about perfect for my ears. After a couple of builds with that alignment philosophy, reaching for lowest possible f3 seems pretty misguided.

The U18 seems to lack nothing and the CSS LD25X (the good pair provided by Dan N.) seem to be very clear and clean up high, the best dome I've heard, lacking only a bit of air compared to my Hiquphon favorites in that regard.

When I listen, I either sit in the middle of the room for the full immersion experience, or music is running in the background, and I am wandering around the house. At this point, I am just looking for trouble so to speak.

For the objective among our merry group, I am past the measuring point, and, as always, a couple of hundred hours of actual listening is needed before I walk away and call them done. In the middle of that. I am sure I could measure things I can't hear, but I can also hear things I would not know how to measure if I was seeking to confirm.

This morning, I cannot detect anything that sounds as I would imagine a beaming issue would sound.

XO is now at 2800, things are sounding really, really nice, however, I need to bring in some boxes of XO parts from the shop again, along with the spaghetti mass of jumpers. Will swap and listen, swap and listen, until it is right. Based on experience, they won't measure as perfectly as the might, but that is not my standard.

[Sydney]

Re: Of what importance is beaming anyway?

... an "objective vs subjective" war. ...

And there is no unanimity in matters of human perception :D

[maynardg]

Re: Of what importance is beaming anyway?

Nor should there be.

And there is no unanimity in matters of human perception :D

[Sydney]

Re: Of what importance is beaming anyway?

Agreed.

[charlielaub]

Re: Of what importance is beaming anyway?

Yesterday, I grew tired of a bit of shouty harshness in some passages coming from the tweeters on the Last Hurrahs. Tweeters are a good pair of LD25X over the 6.5" Seas U18. XO moved from 2500 up to about 2800. Harshness gone. Sound was good before, seems glorious now. However, the XO is clearly in the region where midrange beaming is supposed to potentially start being an issue. I have not measured off axis, but I can detect no fall off, or issues of any kind.

Just how important is beaming and under what circumstances could one be expected to hear the effects? What are the exacerbating or moderating factors in audibility?

When you change the crossover frequency, you are also changing the phase rotation of the HP and LP filters. These interact with the drivers own phase responses. What could be happening is that you have ameliorated an on or off axis hump in the response that you were hearing when the crossover frequency was lower. It could be that, or it could be something else. Without good on and off axis measurements you can only guess what your ears are telling you.

[Tin_Ears]

Re: Of what importance is beaming anyway?

When you change the crossover frequency, you are also changing the phase rotation of the HP and LP filters. These interact with the drivers own phase responses. What could be happening is that you have ameliorated an on or off axis hump in the response that you were hearing when the crossover frequency was lower. It could be that, or it could be something else. Without good on and off axis measurements you can only guess what your ears are telling you.

I'm not focused enough on this subject so I'll just sit in the middle on this one. Scroo everyone else who may have a different aural perspective.:D