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Philharmonic Audio - Dennis Murphy - Page 143

post #4261 of 4614
Quote:
Originally Posted by Nethawk View Post

Why only sometimes? Is the inconsistency based purely on the cabinet design and limitations on offset distance?

I think the word sometimes means that diffraction effects are observed, but not at all wavelengths, and not at all seating positions.
post #4262 of 4614
This is an over simplification, but you can intuitively see why there could be effects. Sound pressure comes from the tweeter. This expands throughout the room and also expands over the front of the speaker. The front holds that pressure as the wave expands. At the edge of the speaker the front is no longer there so the pressure is released. This causes a quick change in pressure. The sound from this change in pressure radiates from the edge. There is a dominate frequency that is from the sharp edge. It is the same frequency from the left and right sides of the speaker. The sound from the left and the right sides combine at your ear and cause a very slight dip at the dominate frequency with the direct sound from the tweeter. This is because both sides are in phase since they are generated from the same sounds from the tweeter. This is so small it probably is very hard to hear. Having unequal distances to the edge means the sound from the edges won’t be in phase and so won’t cause as big a dip. As a side issue, rounding the edge will broaden the edge sound pulse so it is not as sharp a pressure change and be even harder to hear. I hope this makes some sense.

Bob
post #4263 of 4614
Quote:
Originally Posted by fsimms View Post

This is an over simplification, but you can intuitively see why there could be effects. Sound pressure comes from the tweeter. This expands throughout the room and also expands over the front of the speaker. The front holds that pressure as the wave expands. At the edge of the speaker the front is no longer there so the pressure is released. This causes a quick change in pressure. The sound from this change in pressure radiates from the edge. There is a dominate frequency that is from the sharp edge. It is the same frequency from the left and right sides of the speaker. The sound from the left and the right sides combine at your ear and cause a very slight dip at the dominate frequency with the direct sound from the tweeter. This is because both sides are in phase since they are generated from the same sounds from the tweeter. This is so small it probably is very hard to hear. Having unequal distances to the edge means the sound from the edges won’t be in phase and so won’t cause as big a dip. As a side issue, rounding the edge will broaden the edge sound pulse so it is not as sharp a pressure change and be even harder to hear. I hope this makes some sense.

Bob

That's basically it. At some frequencies, the lag from the diffraction pressure wave may be in phase with the main pulse, and you can get a peak. Move the mic our your ear a little left or right, and the relationships change. If you don't toe in your speakers, the first arrival sound will be from a little off axis, so I'm not sure it's worth trying to achieve perfection on axis. Just how audible all this is remains open to debate. I've found that good edge treatment is more important than futzing with tweeter offset. If I really thought offset was important, I would implement it, since it's free.
post #4264 of 4614
Quote:
Originally Posted by Dennis Murphy View Post

That's basically it. At some frequencies, the lag from the diffraction pressure wave may be in phase with the main pulse, and you can get a peak. Move the mic our your ear a little left or right, and the relationships change. If you don't toe in your speakers, the first arrival sound will be from a little off axis, so I'm not sure it's worth trying to achieve perfection on axis. Just how audible all this is remains open to debate. I've found that good edge treatment is more important than futzing with tweeter offset. If I really thought offset was important, I would implement it, since it's free.

By putting them off center you are creating some lobing effect… probably very small? Do you do the crossover differently to account for a different on axis listening distance (Tweeter vs woofer)? So, you reduce diffraction issues… and maybe increase lobing effects by putting them off-center. Probably both exist more in theory in this case, than in an audible difference. Then there are the old AR-3a designs where the tweeter and mid appear to be randomly positioned, with a big frame creating nice diffraction waves. Life was simple in the 70s, wasn't it?

Side question… When I look at Jeff's diffraction FR curves… I see considerable jaggies, or rough curves. I also see that when looking at general FR curves for your speakers (and Jim's). For instance on the Phil3 from 5k to 10k there are about 7 rises and dips (maybe 1db between peak and valley). I have always assumed that this was measurement error. Is this roughness from diffraction.. or is it more random? i.e. measurement error.
post #4265 of 4614
Quote:
Originally Posted by D54Smith View Post

By putting them off center you are creating some lobing effect… probably very small? Do you do the crossover differently to account for a different on axis listening distance (Tweeter vs woofer)? So, you reduce diffraction issues… and maybe increase lobing effects by putting them off-center. Probably both exist more in theory in this case, than in an audible difference. Then there are the old AR-3a designs where the tweeter and mid appear to be randomly positioned, with a big frame creating nice diffraction waves. Life was simple in the 70s, wasn't it?

Side question… When I look at Jeff's diffraction FR curves… I see considerable jaggies, or rough curves. I also see that when looking at general FR curves for your speakers (and Jim's). For instance on the Phil3 from 5k to 10k there are about 7 rises and dips (maybe 1db between peak and valley). I have always assumed that this was measurement error. Is this roughness from diffraction.. or is it more random? i.e. measurement error.

When taking measurements, I position the mic on axis with the tweeter, and tell the software that the tweeter is offset. The AR-3a was a nightmare. I just finished optimizing a pair with a new crossover--there is no "correct" mic position. If you optimize it flat on axis, it will be wildly wrong off axis either to the left or right, or both. So I took three different measurements--to the left, right, and on axis and fiddled until the response was kind of reasonable for all 3. It sounds like a really good bookshelf speaker now, although it will never have the transparency you could get if AR had just lined up drivers and flush mounted the baffle. They do look cool, however.

As for my published measurements, those are totally unsmoothed. I imagine there are some edge diffraction effects there, but also some bobbles from direct reflection off of the baffle. I've never seen an unsmoothed quasi-anechoic measurements that didn't have those ripples in it. The ear doesn't process those, however. John Atkinson and Vandersteen had a raging debate in Stereophile over John's measurements for the superb Vandersteen model 7. They showed cyclic ups and downs in the midrange response that were actually reflections off of the posts that held the wrap-around grill fabric in place. They looked like a disaster in the plots, but they just aren't audible. What is audible is inherent dips in peaks in the drivers or crossover integration, often associated with delayed energy.
post #4266 of 4614
Looks like somebody is getting ready for CAF

I spy, Dennis' Maple 3's, the standard Slims (not Salk), the Philharmonitors, and finally a brand new pair of unfinished Oak Phil 3's. Plus a ton of AVA equipment that I know I'd kill to have.

post #4267 of 4614
Quote:
Originally Posted by fuzz092888 View Post

Looks like somebody is getting ready for CAF

I spy, Dennis' Maple 3's, the standard Slims (not Salk), the Philharmonitors, and finally a brand new pair of unfinished Oak Phil 3's. Plus a ton of AVA equipment that I know I'd kill to have.



Well, you missed the olive burl 3's, and the white subwoofer. The pile of boxes from Van Alstine includes a new all-tube preamp and his magic ABX switching preamp. It should be fun to have visitors to my room
switch back and forth between the Phil 3's, Slims, and monitors. I'll also have some reconstituted Acoustic Research AR3a's and AR4x's. And maybe even some chocolate chip cookies. Worth a visit. to Room 615
And Jim Salk will be right next door.
post #4268 of 4614
I hope Dennis has a strong back. That's a lot of lifting.

So I've had the Phil Slims for a little bit now. I bought a receiver July 5th (Denon 3313) and hooked them up to it while I await more equipment.

What can I say, they sound marvelous. I didn't really expect anything else but I was pleasantly surprised at just how good they sound. I could tell on a few tracks that they didn't reach quite as low as the Phil 3's but the 3's have a tremendous bass response. I could easily play these without a subwoofer for two channel use all day long. Highs and mids were what I've come to expect from Mr. Murphy - sweet and airy with uncanny clarity and realism. These speakers are really great.

One of my favorite test tracks is Joanna Newsom's "The Book of Right On" from her "Milk Eyed Mender" album. There is an incredibly powerful bass that made my Magnepan 3.7's flap and my Soundfield Audio M-1's buzz. The Phil 3's just played it without any audible (to me at least) distortion. The Phil Slims played it fine as well though the bass wasn't as deep as with the 3's. The vocals on that track range from sublime to harsh which is purely a function of her voice. The Phil Slims sounded as good as the 3's to my ears. I could definitely tell it wasn't playing on the AI tube preamp and AVA amp but the sound was still very good through the Denon. The harp she plays has dancing notes that just float above and forward of the speakers with the right room/equipment and her voice just floats in the air. This sounded awesome on the Slims.

I played some rock (Pink Floyd - Mother, Fat Old Sun, and Great Gig in the Sky) and they rocked out with the best of them. I love vocals and instruments through these.

In short, and apologies for the rambling post, these are a great addition to the line. They look and sound great. My wife loved the looks of these which is a nice bonus. She definitely likes the looks of these over the 3's.
post #4269 of 4614
I am curious, who does the heavy lifting for these shows? The hotel? Does each vendor take responsibility for moving in their own stuff? A union?
post #4270 of 4614
An aging retired economist does the heavy lifting. With a little help from my friends. With a lot of luck, I might get one of the hotel employees to hold a door open for us. Fortunately, the unions aren't involved.
And thanks for taking the trouble to report your initial reactions to the Slims, littlejeans. I finally built a speaker you don't have to sneak by the spouse. Go figure.
Edited by Dennis Murphy - 7/17/13 at 4:26pm
post #4271 of 4614
Quote:
Originally Posted by Dennis Murphy View Post

An aging retired economist does the heavy lifting. With a little help from my friends. With a lot of luck, I might get one of the hotel employees to hold a door open for us. Fortunately, the unions aren't involved.
And thanks for taking the trouble to report your initial reactions to the Slims, littlejeans. I finally build a speaker you don't have to sneak by the spouse. Go figure.

What about getting that subwoofer to help you some? biggrin.gif
post #4272 of 4614
My next center channel speaker is missing from the photo. If I weren't going to be among hemp skirts and the scent of potpourri, that's the one I'd volunteer to carry.
post #4273 of 4614
Dennis, strange things at your site. Click on Discussion Forums and you get a message that this is an adult site (?) and it's out of credits (?)

Now I know I lust after the Phil Slims and I guess your speakers may qualify as speaker porn, but there may be a mistake somewhere.
post #4274 of 4614
Quote:
Originally Posted by BarnacleBill View Post

Dennis, strange things at your site. Click on Discussion Forums and you get a message that this is an adult site (?) and it's out of credits (?)

Now I know I lust after the Phil Slims and I guess your speakers may qualify as speaker porn, but there may be a mistake somewhere.

Well that's one way of attracting new customers. Now my two favorite hobbies can be found in the same place!
post #4275 of 4614
Quote:
Originally Posted by Monkish54 View Post

Well that's one way of attracting new customers. Now my two favorite hobbies can be found in the same place!

I knew I could come up with a successful business plan if I kept at it long enough.
post #4276 of 4614
Quote:
Originally Posted by BarnacleBill View Post

Dennis, strange things at your site. Click on Discussion Forums and you get a message that this is an adult site (?) and it's out of credits (?)

Now I know I lust after the Phil Slims and I guess your speakers may qualify as speaker porn, but there may be a mistake somewhere.

This issue may be on your end; either your DNS error or malware
post #4277 of 4614
Quote:
Originally Posted by Dennis Murphy View Post

Quote:
Originally Posted by Monkish54 View Post

Well that's one way of attracting new customers. Now my two favorite hobbies can be found in the same place!


I knew I could come up with a successful business plan if I kept at it long enough.
Uh oh... new front ported Philharmonic design in the works? LOL


Max
post #4278 of 4614
Quote:
Originally Posted by Eternal Velocity View Post

This issue may be on your end; either your DNS error or malware


Hmmmmm. When I click on Discussion Forums in either Chrome or IE, all I get is a big old "Website" placeholder. Are you sure you're not just seeing a ghost image from the last website you were on?
In any event, you should buy some credits.
post #4279 of 4614
Happens to me too Dennis using an iPad,
post #4280 of 4614
Quote:
Originally Posted by Chu Gai View Post

Happens to me too Dennis using an iPad,


I feel strangely cheated. It didn't happen on my iPad.
post #4281 of 4614
Quote:
Originally Posted by Dennis Murphy View Post

I feel strangely cheated. It didn't happen on my iPad.

Didn't happen on my iPad either.
post #4282 of 4614
Quote:
Originally Posted by Chu Gai View Post

Happens to me too Dennis using an iPad,

I'm glad to know it's not just me. It's still there today.
post #4283 of 4614
Quote:
Originally Posted by BarnacleBill View Post

I'm glad to know it's not just me. It's still there today.


Have you tried it in the last hour?
post #4284 of 4614
I tried a bit ago and just got a website under construction graphic.
post #4285 of 4614
Quote:
Originally Posted by mrlittlejeans View Post

I tried a bit ago and just got a website under construction graphic.


Thanks--I think the little gremlin has been apprehended.
post #4286 of 4614
Fillharmonic Instruments!

Dennis, someone's cannibalized your speaker name! I think you'll like it anyway!
http://www.upworthy.com/watch-the-first-54-seconds-that-s-all-i-ask-you-ll-be-hooked-after-that-i-swear?g=2&c=upw1

Not trying to hijack the thread, just an interesting tangent while waiting for CAF.
Edited by M S - 7/22/13 at 7:50pm
post #4287 of 4614
Somehow I don't think I'll be suing them for copyright infringement. That's really beautiful. They turn trash into music. Most people who've heard me play violin think I turn music into trash. But hopefully that's not true of my speakers. Thanks for the post.
post #4288 of 4614
Quote:
Originally Posted by Dennis Murphy View Post

Somehow I don't think I'll be suing them for copyright infringement. That's really beautiful. They turn trash into music. Most people who've heard me play violin think I turn music into trash. But hopefully that's not true of my speakers. Thanks for the post.

LOL There is plenty of testimony in this thread that your speakers do not turn music into trash. If the music happens to be trash........well, garbage in, garbage out. smile.gif

If your playing was that bad, they would have kicked you out long ago.

Hope you have a great showing at CAF. Let us know if you ever show the Slims near Chicago.

Marv
post #4289 of 4614
Good luck and have a great time at CAF, Dennis! Remember, bend at the knees. wink.gif
post #4290 of 4614
Quote:
Originally Posted by Mudslide View Post

Good luck and have a great time at CAF, Dennis! Remember, bend at the knees. wink.gif

What knees? Fortunately my main men Travis and Richard will be there to help with the heavy lifting. Actually, I think those restored AR3a's are the heaviest. There's been progress made on woofer magnet efficiency.
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