Lascala cabinet resonance

[OO1]

........

[Tom05]

I hate the word resonance in this context , seems like such a  derogatory word to describe  the  Klipsch Lascala . Many will get the wrong idea of what this supposed deficiency even means, they may think of a rattle ,like in a cars dashboard or the buzz of dishes resonating in a cabinet . What could be observed ,( if anything ) in this case , is a  narrow peak in frequency response . Peaks are caused by many things not always related to resonance, resonance is not a good way to describe the performance of Lascala . I love the voice of Lascala, and  Klipschorn , resonance/annoying peak  —. I don’t hear it . But I can’t speak for everyone .

[Tom05]

double  post .

[Schu]

I LOVE the word resonance... because that is what acoustic instruments do.

[Tom05]

26 minutes ago, Schu said:

I LOVE the word resonance... because that is what acoustic instruments do.

On 12/16/2023 at 8:33 PM, Schu said:

Everything resonates to some extent... even my teeth resonate.

Ok

[Schu]

Life and matter resonate...

[Islander]

On 12/19/2023 at 10:00 AM, JohnA said:

 

I have 1980 LA Scala's.  It appears to me that the bass horn has 2 minor issues.  The similar Peavey FH-1s I owned and tested had a similar response rise between 100 and 200-ish Hz.  In addition, my La Scala's sidewalls will vibrate, but I didn't notice (and feel it) it until I played "I Don't Need No Doctor" at concert levels.  I'm sure I was peaking over 100 watts.  Later that session I lost 4 subwoofer drivers to heat!  At more sane levels, 100 dB and under, I don't hear or feel anything.  The AL-5 La Scalas can only be better, less resonant at high volumes. 

 

I got to spend 30+ minutes with them alone in a room at the KHMA at Subfest.  Even at quite loud levels, they were polished and refined and threw a stereo image that make mine envious.  Though instantly familiar, I did not notice the "resonance" at peaks easily approaching 100 dB. 

 

Bottom line, everything flexes, bends and resonates, but this is an overstated issue when the speakers are used at home and the resonance can be enjoyable on some music. 

 

See my quote above.

[Islander]

On 12/21/2023 at 7:19 AM, Tom05 said:

I hate the word resonance in this context , seems like such a  derogatory word to describe  the  Klipsch Lascala . Many will get the wrong idea of what this supposed deficiency even means, they may think of a rattle ,like in a cars dashboard or the buzz of dishes resonating in a cabinet . What could be observed ,( if anything ) in this case , is a  narrow peak in frequency response . Peaks are caused by many things not always related to resonance, resonance is not a good way to describe the performance of Lascala . I love the voice of Lascala, and  Klipschorn , resonance/annoying peak  —. I don’t hear it . But I can’t speak for everyone .

 

 

Many people confuse resonance peaks with inherent peaks.  The shape of the La Scala and La Scala II (and presumably the AL-5) bass horn is the cause of the notorious 148 Hz peak.  It is not due to any kind of resonance.  Naturally, it's more audible at higher volumes, but it measures the same on both the 3/4" plywood OG La Scala bass horn and the 1" MDF horn of the LS2.

 

As most of you are aware, I enjoy my modded bi-amped 2-way La Scala IIs.  Their crossovers are disconnected, and the EQing is done with an Electro-Voice Dx-38 processor, which also provides time alignment between the woofers and tweeters.  The point is that Roy supplied the settings for both generations of La Scalas, and the settings he provided are the same for old LSes and for LS2s.  The settings provide for a 7 dB cut at 148 Hz, which gives a flat bass response.  If there's a resonance from the less than absolutely rigid sidewalls, I've never heard it.  Maybe I don't play my system loud enough, or maybe I'm half deaf.  I never heard it when the original LSes were 3-way and used their original AA crossovers.

 

•  

[Flevoman]

Thank you so much for the effort you've put into this, @mikebse2a3. This really gives me some insight. When I listen to your audio file, I can clearly hear the thickening. It might not be as pronounced as on the La Scala, but this could be due to the recording and playback through my earphones. I recorded a piece of music with my phone and listened through earphones to compare with your recording, and they sound quite similar through the earphones. It's not conclusive yet; it might still sound a bit more pronounced on my end. However, I'm starting to think that what I sometimes hear as a resonance is likely present in the song itself, enhancing the La Scala and possibly amplified a bit more in my acoustic environment, making it unpleasant for me. I'll mention it here when I come across another track. Could you please test it again on your La Scala to see if you can hear it too?

[mikebse2a3]

11 hours ago, Islander said:

Many people confuse resonance with inherent peaks.  The shape of the La Scala and La Scala II (and presumably the AL-5) bass horn is the cause of the notorious 148 Hz peak.  It is not due to any kind of resonance.

 

What is it about the shape that causes the 148Hz peak… ?

 

Looking at the Impedance Plots seem to indicate resonances of mechanical/acoustical nature.

 

Finite horn length and mouth size cause reflections in the horn due to impedance mismatching at the mouth/room interaction leading to what I understand to be standing waves and resonances in the horn.

 

@Chief bonehead maybe you can clarify what causes the 100Hz - 200Hz region of frequency/phase anomalies of the La Scala models.

 

miketn

[Flevoman]

Same for this song. 

When the piano goes down (1:50 and 1:58 for example) I hear the resonance. 

The song is overal in balance, and at these moments the piano sounds thick with some resonance. The air in the music is gone, it sounds a bit fat/thick.

[mikebse2a3]

10 minutes ago, Flevoman said:

Thank you so much for the effort you've put into this, @mikebse2a3. This really gives me some insight. When I listen to your audio file, I can clearly hear the thickening. It might not be as pronounced as on the La Scala, but this could be due to the recording and playback through my earphones. I recorded a piece of music with my phone and listened through earphones to compare with your recording, and they sound quite similar through the earphones. It's not conclusive yet; it might still sound a bit more pronounced on my end. However, I'm starting to think that what I sometimes hear as a resonance is likely present in the song itself, enhancing the La Scala and possibly amplified a bit more in my acoustic environment, making it unpleasant for me. I'll mention it here when I come across another track. Could you please test it again on your La Scala to see if you can hear it too?

 

@Flevoman   I would ignore the sound on that clip as far as any reference to listening to it since it was just picked up by my iPhone while filming the RTA display showing the frequency spectrum of energy when you experience the resonance sounding issue. I included the sound just so we could match the spectrum display with what was occurring in the song at any given time.

 

Note: The RTA is receiving line level input so that we see only what is in the recording itself without any loudspeaker/mic/room interference. I wanted to see the actual recordings frequency response during the problems you experienced.

[mikebse2a3]

2 hours ago, Flevoman said:

Same for this song. 

When the piano goes down (1:50 and 1:58 for example) I hear the resonance. 

The song is overal in balance, and at these moments the piano sounds thick with some resonance. The air in the music is gone, it sounds a bit fat/thick.

 

 

 

@Flevoman The mix of this song is interesting.

 

On the Audeze/McIntosh headphone system the sense of air/spaciousness during vocals is obvious but as the passage when the piano plays it is as if it is distant and closed in somewhat and a bit muddy sounding in comparison to other parts of the mix and the sense of spaciousness and air are definitely reduced.

 

The La Scala AL5 system gives a very wide soundstage with good depth and airiness during the vocal passages but again during the piano passage it sounds distant and somewhat closed in and lacking clarity and muddy sounding and the sense of spaciousness and air are definitely reduced in comparison to other parts of the mix. I can’t say I hear a particular resonance during this but more just a mix that goes from open, spacious and airy during the vocal passages to closed, distant, somewhat muddy on the piano passage.

 

The UG Jubilee system gave me pretty much the same experience as the La Scala AL5 system with added low frequency detail below what the La Scala AL5 provides by design.

 

miketn 

[Flevoman]

@mikebse2a3 

Thanks again for the help Mike.

I recognize what you're saying, and exactly this is what bothers me. The recording sounds dynamic with air and space between the vocals and instruments. However, in the part where the piano goes deep (e.g., at 1:50 and 1:58), it sounds like it's strugling and thickening. Tonally, it most resembles something woody that briefly vibrates, causing distortion. This effect undermines the experience that the La Scala gives me with this track, the effortless reproduction of the music.

This effect is less pronounced than in Chris's track. Still, what I hear in this track, less intense but quite noticeable, I experience fairly regularly in other tracks too. However, apparently, this effect is less strong for you than for me (at least, that's the impression I'm getting). I'm starting to think it's not the speakers themselves but more a combination of recording, speakers, and my acoustics.

Can you perhaps check if this is at the same Hertz as with Chris? 

Just curious... 

[Khornukopia]

@Flevoman Maybe you have already mentioned, but at what SPL does this condition begin to happen? Also, have you tried a different amplifier?

[mikebse2a3]

4 hours ago, Flevoman said:

Can you perhaps check if this is at the same Hertz as with Chris? 

Just curious... 

 

@Flevoman Here is a 20 sec clip from ~ (1:38 to 1:58)

 

 

[mikebse2a3]

4 hours ago, Flevoman said:

However, apparently, this effect is less strong for you than for me (at least, that's the impression I'm getting). I'm starting to think it's not the speakers themselves but more a combination of recording, speakers, and my acoustics.

 

@Flevoman Yes the mix of the recording is the predominate issue IMO and any issues with room acoustic and speaker setup could make it a worse experience.

 

I will say if you are using any amplifiers with low damping factors like many Single Ended Tube types then definitely try using the 4ohm and 8ohm taps to see which sounds best. These amplifiers in combination with speakers having variable impedances across their spectrum will experience tonal balance influences and you will want to decide which sounds best in your system.

 

miketn

[Marvel]

12 hours ago, mikebse2a3 said:

Yes the mix of the recording is the predominate issue IMO and any issues with room acoustic and speaker setup could make it a worse experience.

I think this is the issue with a LOT of recordings, where there are discrepancies in the acoustic space of different tracks in a mix. You might not even notice listening on some generic direct radiator speakers.

 

The more resolving they are, the more apparent it is.

[Flevoman]

@Khornukopia yes, I have tried different amps. All tubes by the way.

And the warmer the tubeamp

sound the more I can hear it.

 

@mikebse2a3 thank you again Mike 👍🏻.. Unfortentaly I don't know anything about damping factor or what it does. But I will try the 4 Ohm tab just to see if this makes any difference. 

 

@Marvel

If this is true, the more resolving they are, the more apparent it is, how come nobody else recognise directly what I am hearing on my system? Just trying to understand things. 

[KT88]

54 minutes ago, Flevoman said:

@mikebse2a3 thank you again Mike 👍🏻.. Unfortentaly I don't know anything about damping factor or what it does. But I will try the 4 Ohm tab just to see if this makes any difference. 

 

 

Put simply, the damping factor is a measure of the control an amp has over the speaker. The damping factor is another way of reading the output impedance of a power amplifier. But even a very high damping factor is not ideal. Then speakers can sound cold and unmusical. On the other hand, these exotic super-low-wattage amps often have a damping factor that is far too low, which means that the frequency response is no longer linear, but a mirror image of the frequency-dependent input impedance of the speaker, with lots of bends and irregularities. Even the fact that a horn speaker could in principle cope quite well with an amp with too low a damping factor is torpedoed by the fact that the xover is not at all as simple as the horn itself. In principle, the use of weak SET amps is always a game of roulette and requires a lot of try and error. Amps with a poor damping factor work best with broadband drivers without xover, such as Lowther in a horn.
Even if it's just my guess, too low a damping factor can cause such an amp to begin to resonate partially, causing unpleasant resonances like those in Chris Isaak's voice. It's all a question of priorities. Personally, I have found that SETs sound like paradise at the beginning and that after a while my impression is that they colour everything euphemistically, which I mean negatively.