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Advice for Beginners - consider this test from an audio club


ODS123

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8 hours ago, Max2 said:

No its there.  I don't know if they recorded with a pickup in the acoustic or used a mic, but his hammer on with  A7 I think is very harmonic as well as much more of his or her finger work in the song. That guitar could very well have a nasty resonation.  The Tune finishes out much better than its starts.

Max2 would appear to agree with this as well.

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6 hours ago, kink56 said:

Oh I hear that on my Fortes and my old (now my friend's) ProAc Super Towers. But only the 120hz-150hz hump on the Belles and someone else's Khorns. I cannot imagine that hump would ever show up on even mediocre headphones.

One recording is hardly sufficient to dismiss all of Klipsch's speakers with a smaller bass bin.  If this is an actual issue, please provide other examples of recordings that cause this problem.   

 

A hump in the bass response and a distorted recording are two separate things.  Being able to hear distortions present in a recording better because one speaker is more resolving than another is not at all an indication that the more resolving speaker is not as good as the less resolving speaker.  In fact, the opposite is true.  Khornukopia's headphone test would appear to confirm this as well. 

 

It would appear that kink56 is mixing up a response hump with a distorted recording and coming to a conclusion that is not valid.  A speaker with the muddy bass response of many DR vented cabs would probably also not resolve the distortion present in this track.  A DR with a passive radiator might be even worse. 

 

I will re-listen to the Birds song at higher volume again on my LS to confirm my earlier listening session.  I will also listen to the Birds song on my upgraded Heresy II as well to see if I hear it.  My Quartets are out on loan unfortunately, they are the closest thing I have to a Forte.         

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I listened to Birds again, this time on a pair of Martin-Logan electrostatic speakers. 


The recording has a sub-sonic rumble that is overloading the recording apparatus, thereby creating distortion to the entire recording. I can't identify if the rumble is from wind blowing across the microphone, or some heavy industrial noise in the background.

 

Pleasant song, but the recording is noisy and distorted. The song is a poor choice for speaker demonstrations.

 

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15 hours ago, dwilawyer said:

Dean, you heard an "upper bass thump" on Khorns?  Resonance on LS IIs?  On Jubilees?  At all speaker levels?

 

Where do you discuss that? 

 

Nobody mentioned it when we had a Khorn and a Jubilee side by side with an AB switch box and pink noise and demo disks for 3 hours (that was just with the Khorn).

 

"Upper level bass thump" is measurable, easily measurable.   Resonance is also easily measurable and you can determine what music will expose it, what music will nearly or completely mask it, and whether it is audible.

 

I didn’t say anything about an “upper bass thump”. And I didn’t mention Klipschorns, LaScala II’s or Jubilees. I said, “older Klipsch stuff”, and I was specifically thinking of the Heresy, Heresy II, Cornwall, Cornwall II, Chorus, Chorus II, and LaScala. I’ve never heard the Belle. 

 

All of these speakers fail the simple knuckle rap test. There is no internal bracing, and internal resonances cause the panels to vibrate. You can lay your hand against a panel and feel it vibrating, and a moving box is not silent. Naturally, it’s more noticeable when you turn it up. The larger the panels, the more you can “hear the box”.

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13 hours ago, Coytee said:

 

Having owned LaScalas since 1979 (bought them new) and having heard the LaScala II, my opinion is, the II's "sound" like they have a full (additional) octave of bass.  When I asked about it to some of their engineers, he (Jim Hunter) admitted to me that the same output is there in the original LaScala, it's just masked by all the vibrations of the sidewalls.....if you could tame those, you'd hear that lower sound that the II's have.

 

 

Very useful bit of information...When listening at a below moderate volume level, could not hear the hump as some put it or the null in the frequency, even with around 84 vintage crossovers AL-3. Suppose at moderate to higher levels, would have noticed.

Thanks! 84 LS1

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13 hours ago, kink56 said:

Interesting. I have always thought it was the cabinet being excited by that frequency.   So if it is the horn design, the new La Scala isn't that much different in bass bin design (horn configuration) from the La Scala I to alleviate this problem then? 

 

The bass horn of the La Scala II is a little bit different from the first-generation bass horn.  It's about 1"/2.5 cm. longer, but that's about the biggest difference, other than the 1" MDF construction.  However, it's enough to make an audible difference.  The bass may go a tiny bit lower, but there seems to be more of it, which makes it sound like the LS2 bass response does go deeper.

 

As for the 148 Hz. hump, it's still there, but it may be less noticeable, what with the improved bass response.  Personally, I barely noticed it on the 1st-gen La Scalas, and after owning them for about 18 months, I converted them to JubScala spec., which converts them from 3-way with a passive crossover to bi-amped 2-way with an active electronic crossover, and of course the Jubilee tweeter, with either the typical-sized 510 horn, or the giant 402 horn.  Roy Delgado, who put the combo together, as well as the actual Jubilee when he and Paul Klipsch worked together, included a setting in the programming of the E-V Dx38 processor/crossover that eliminates that upper-bass hump.

 

So converting La Scalas into JubScalas gets rid of the 148 Hz. hump, and smooths out a few other irregularities in the frequency response, but it's not cheap.  If you don't already have a pair of La Scalas or La Scala IIs, it would be a good idea to look into full Jubilees, which also benefit from being bi-amped, with the active crossover that corrects any frequency response issues far better than a passive crossover ever could.

 

A much cheaper option would be to not play the very few recordings that make that upper bass hump noticeable, especially if it's not the kind of music you usually listen to.  It's quite likely that it's possible to find a few recordings that will expose rarely-heard weaknesses in certain good speakers, but not other speakers.  For instance, nobody would recommend listening to death metal at high volume on an electrostatic speaker, would they?  The perfect speaker has never been built, and may never be built.  Therefore, the speaker that makes you the happiest the most of the time is the best speaker you can get.

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1 hour ago, Deang said:

All of these speakers fail the simple knuckle rap test. There is no internal bracing, and internal resonances cause the panels to vibrate. You can lay your hand against a panel and feel it vibrating, and a moving box is not silent. Naturally, it’s more noticeable when you turn it up. The larger the panels, the more you can “hear the box”.

 

another audiophile myth.  I've heard numerous unbraced speakers that did not exhibit audible resonances.  ..Including my current CWIII's

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Hey the sub sonic rumble is not what I am talking about.  And yes, that subsonic rumble would play havoc on electrostatic speakers. It would easily cause electro-stats to over modulate. That is not the issue.  My system with my subwoofers easily handles that subsonic rumble and does not taint the rest of the recording

 

  I have heard the problem I am talking about with other recordings, but I really do not remember the exact recordings. Some were ECM jazz recordings.   No, it is not the said distortion of the acoustic guitar that is causing the problem.  The problem is if a recording has significant material in the 120h to 150hz range, especially if the instrument is struck or plucked (transient in nature) the inherent 7dB hump in the Belles is especially going to exaggerate those tones. It is simple science. It actually would be worse than using a graphic equalizer and only boosting 120hz-150hz up 7dB.     And the problem is not going to show up in any significant way with Forte, Heresy, Cornwall or any of the direct radiating Klipsch speakers.  It does not show up on headphones or any other speaker I have ever heard.  So, unless you have a Belle, a La Scala or maybe even a K-horn, this is not going to be an issue.   I am not complaining about the recording or the song.  I just simply used that one song to take to the guy with the K-horns to find out if they had a similar problem that my Belles had. 

 

The reason ECM recordings are also a problem is the acoustic bass.  Jazz bass players love to play (noodle) way up the scale and they easily and often get into the 150hz area.   So it rendered ECM recordings unbearable for me too.    And they are typically very well recorded.  In fact when I tire of poorly recording popular music of all kinds, I throw on an ECM recording just to get my bearings back. 

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13 minutes ago, kink56 said:

I am not complaining about the recording or the song.  I just simply used that one song...

 

Yes, you picked the song, and are using a poorly recorded song with a high level of sub-sonic noise and distortion as your favorite demo song. 

 

13 minutes ago, kink56 said:

And yes, that subsonic rumble would play havoc on electrostatic speakers.

 

Why do you say that that? The electrostatic speakers with separate subwoofers are not distorting, they are accurately playing your bad demo. I used these speakers to avoid you saying I have a preferential bias toward Klipsch speakers.

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13 hours ago, garyrc said:

 

I have Khorn R & L, with a Belle center.  The Belle showed a slight resonance at high SPL, very rarely.  I was going to flushmount it in the wall between the Khorns anyway, so I arranged to put some damping pressure on both sides, the back and the bottom.  That got rid of the rare resonance. 

 

My Khorns are pressed into the corners, with a gasket which makes for a tight seal -- no resonance.  The walls near the Khorns are very firm, made of about 10" O.C.  2X6s, covered by 3/4 voidless ply, which in turn is covered by 5/8" sheet rock, screwed and glued, with seams staggered.  In our former house, the nearby walls were the same, except the plywood was covered by walnut veneer.  No resonance there, either. 

 

I did see walls once that bounced in and out under the influence of Khorns, and they, the walls, did resonate.  How firm are your friend's walls?

Post some of those great curves you are famous for so they can really u understand.

 

Include the distortion ones as well.

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Well if your electro-stats have a subwoofer then you are right, it would not affect the electro stat portion of your speakers to over modulate.   It is not my favorite demo song. It is my demo song to demonstrate the problem easily. 

 

So, if no other speaker other than Belles and K-horns (in my experience) presents a problem in the 120-150hz area then how it is the recording fault?   This recording sounds just fine on my Fortes and my Heresys, and on ProAc Super towers and so on. Yes the rumble is still there, but that rumble does not make the acoustic guitar E and A string on that recording sound so extremely fat and blurred. And the same goes for acoustic bass on my ECM recordings in that frequency range.  There were other popular albums with acoustic guitar that presented the same problem, but I do not recall them.    I used this recording to demonstrate the problem because it is probably the most extreme and easiest to hear if anyone is going to hear or notice it at all other than myself. 

 

I have heard both Acoustat and Martin Logans back in the 80s, and I liked them enough I considered buying them. These particular models did not have a dynamic direct radiating woofer like more recent models do. They all but required you also buy a separate subwoofer (which I already had by then anyway). 

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So we have those who acknowledge the Belles and La Scalas have the 7 dB hump around 150hz. But then there are others who say it is not the speakers fault and they tear apart the recording. I acknowledge the recording is not perfect, but it does demonstrate that 150hz problem effectively. But then again, there are some who cannot hear a problem.   So, it is a mixed bag.  

 

It reminds me of how Christian "scientists" try to demonstrate how the Grand Canyon is evidence for the great flood.  Some would rather blame ANYTHING than consider the Belles may have a problem with frequency response.  (hey all they are doing is 100% accurately revealing exactly what is on the recording or the weaknesses of the amp, the room, and so on). 

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33 minutes ago, Khornukopia said:

 

Yes, you picked the song, and are using a poorly recorded song with a high level of sub-sonic noise and distortion as your favorite demo song. 

 

20 minutes ago, kink56 said:

 It is not my favorite demo song. It is my demo song to demonstrate the problem easily.  

 

12 minutes ago, kink56 said:

So we have those who acknowledge the Belles and La Scalas have the 7 dB hump around 150hz.

 

A hump in a speaker frequency response is a condition that can be adjusted down. The listening room probably has more humps and dips than that speaker. 

 

Using a poorly recorded song as a demo to point out a speaker's shortcomings seems odd.

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     Anything truly below my enclosed K-Horns capability comes in the form of driver movement or flutter and the speed of it has  to do with what Fr or cycle we're talking about.  That's all I hear in subsonic range on my K's.  I didn't bother kicking my sub on for the "Birds" track as I assumed we were talking about a 100ish hz "thump" that Kink56 had mentioned. I didn't turn it up and rattle the walls, I played it at a conversation level sitting about 12-14' off. I could hear it immediately and as I moved closer it got much worse.  I put my ear closer to the side vent and it was a really bad buzz like the guitar body was doing the resonating or someone wasn't fretting hard enough with their fingers causing the buzz.  Could have been a hot channel, could have been the mixing trying to keep up with her delicate, yet very pronounced voice after the fact. It is plainly on the track and obviously a bass horn is magnifying it.

 

  This is my interpretation, but I didn't use enough power to cause any  resonance in my bass cab.  I guess I could play it through my LaScala rears, but I'm pretty sure its going to be a very similar result with the audible difference being the length of the bass horn.  The Bass horn is simply magnifying what its being fed.   The only rasp or resonance I have heard takes quite a few watts to really rear its head on my old single wall Indy LS's which were my mains for around 15 years.  Like mentioned before, its pretty telling that a DR cab is not producing or should I say, "revealing this."

 

      The K's have a hump, the LS's have a hump, The Belles have a hump and I believe the Jubilee bass cab has its short comings that have to be dealt with as well.   Highly efficient Horn bass cabs are going to have these issues to deal with, but they're still the cleanest, most efficient, lowest THD setup you can build or own.

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1 hour ago, ODS123 said:

 

another audiophile myth.  I've heard numerous unbraced speakers that did not exhibit audible resonances.  ..Including my current CWIII's

 

Your Cornwall III's are braced. I see a Plywood motorboard, but the rest looks like MDF (which helps).

 

It's not a "myth", it's from "Building Loudspeakers 101". Smaller speakers don't suffer from the problem as much because the panels are smaller.

 

Cornwall III's being built. Notice the braces.

 

I think we have a few thousand posts on this forum on how to brace Cornwalls.

 

 

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