ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 [2] 3  All   Go Down

Author Topic: What does an simple SPL number tell you anyway?  (Read 4695 times)

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 9091
  • Atlanta GA
Re: What does an simple SPL number tell you anyway?
« Reply #10 on: June 01, 2017, 07:42:07 am »


So trying to describe something with a simple SPL meter reading often falls short of what the actual experience is.
I have done a couple of shows lately that had some "interesting SPL reading".

These were what you would call "hardcore" type shows in which you would expect the levels to be pretty high.  Hardcore nasty rap-metal bands etc.

There is no SPL limit in the venues, and the systems still had plenty of headroom left.

I let the operators run it as they wanted-unless they would be close to causing damage-which they were not, so I never said anything about the levels.

Keep in mind that there was plenty of low deep freq available-so the energy was there.

The levels at FOH A slow (which seems to be popular these days-it never used to be------Oh well) was around 101-102dB.

Not what you would expect from that type of show, yet the FOH guys and the audiences were happy (and impressed), yet the measured SPL was not as high as at some other shows.

I think this is a good thing, especially when you consider that your ears didn't ring.  Unless of course you like that sort of thing :P

The simple SPL is not always an indicator of the "fun factor" of the overall sound.

Logged
A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Scott Bolt

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1478
Re: What does an simple SPL number tell you anyway?
« Reply #11 on: June 01, 2017, 09:47:47 am »

Actually it really depends on the cabinet.

In almost all of the Danley designs, the HF is the "weak link" due to the fact that the horn loading gives so much extra gain to the low and mids.
I can see that with speakers like Danley.

Lots of speakers have a relatively high cross-over to the horn (1-3K).  I think in these designs the horn isn't as stressed.  The lower you go, the more power it takes to get SPL out.

Seems like (could be a wrong perception) that it is more difficult to prevent distortion in HF than LF though?

I totally agree with you that the "fun" factor is totally missed in an SPL reading!
Logged

Ivan Beaver

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 9091
  • Atlanta GA
Re: What does an simple SPL number tell you anyway?
« Reply #12 on: June 01, 2017, 10:08:57 am »


Seems like (could be a wrong perception) that it is more difficult to prevent distortion in HF than LF though?


There are 2 things to consider when discussing harmonic distortion (the addition of harmonic related freq to the fundamental).

The first is the fundamental freq, the second is the freq of the actual harmonics.

In the case of most of our products, the distortion components are "mechanically/physically" reduced due to the physical low pass filters that are in front of the low and mid drivers.

So any distortion components produced by the drivers (above the low pass freq) are reduced.  This is kind of like how the muffler on your car works.

So lets say the woofers operate up to 300Hz.  If you put a 200Hz tone in, then the harmonics (400,600,800 etc) are reduced AFTER they are created.

You cannot do this with processing, only after the sound exits from the driver.

The HF driver does nto have such a low pass-because it needs to go higher.

However, the harmonic distortion of the driver (especially as you go up in freq) become less of an issue-simply because your ears can't hear them (out of our hearing range).

When you have a lot of horn gain at the lower freq of the HF driver, you end up with a lot of "extra level" that you need to "throw away"-via eq or higher xover freq.

When that range is reduced in level going to the driver, then the driver is going to have a lot less distortion, than a driver that is on a small horn that does not have this gain.

In some cases, we are "throwing away" 15dB of gain.  this means that at those freq, the driver is getting 1/20th to 1/40th of the power at the higher freq.  So the distortion is lower at those freq, and those freq are the ones that will have harmonic content that we can hear. At 2Khz you will have harmonics of 4K-6K-8K-10K etc.

Also remember that the particular harmonics sound different (pleasing) to our ears.

The even harmonics are not distracting.  The odd harmonics are the "bad ones".  So fortunately the odd ones are higher in freq-so they are either out of our range of hearing or start to be in the acoustic low pass filters and reduced.
Logged
A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Lance Hallmark

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 263
  • Tampa Bay, FL
    • Hallmark Events & Entertainment
Re: What does an simple SPL number tell you anyway?
« Reply #13 on: June 01, 2017, 10:46:57 am »

Here is a fun experiment to play-when talking about SPL meter readings and how it sounds.

Take a 3 (or 4) way tri/quad amped system and turn it up to a good comfortable pretty loud level-but still easily listenable.

Now mute everything but the HF (keep the levels the same).

What do you do?  You IMMEDIATELY cover your ears because it is to "loud" and hurts.

But why?  The actual SPL measured is LOWER than before, when you could listen to it.

And the highs will sound really nasty, yet they were clean before.

It is not just the "simple SPL", but rather the balance of the sound/freq ranges that make a HUGE difference in how we perceive loudness.

Our perception of loudness can be VERY different than reality

So trying to describe something with a simple SPL meter reading often falls short of what the actual experience is.

THIS is what so many people don't get when you are talking about higher quality sound systems. Just did a 14 hour show of House music this weekend with zero ear fatigue and never felt that the sound was ever overpowering. Lower quality speakers would have you thinking it's too loud and bring on the headaches and ringing.
Logged
----------------------------------------------------
Lance Hallmark
Hallmark Events & Entertainment
Chamsys, Crown, Danley, EV, JTR, Powersoft, Yamaha

George Friedman-Jimenez

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 502
  • NYC
Re: What does an simple SPL number tell you anyway?
« Reply #14 on: June 01, 2017, 12:06:28 pm »

Here is a fun experiment to play-when talking about SPL meter readings and how it sounds.

Take a 3 (or 4) way tri/quad amped system and turn it up to a good comfortable pretty loud level-but still easily listenable.

Now mute everything but the HF (keep the levels the same).

What do you do?  You IMMEDIATELY cover your ears because it is to "loud" and hurts.

But why?  The actual SPL measured is LOWER than before, when you could listen to it.

And the highs will sound really nasty, yet they were clean before.

It is not just the "simple SPL", but rather the balance of the sound/freq ranges that make a HUGE difference in how we perceive loudness.

Our perception of loudness can be VERY different than reality

So trying to describe something with a simple SPL meter reading often falls short of what the actual experience is.

This is not just perception. The ear has a reflex, the stapedius reflex, that responds to loud sounds by tensing the stapedius muscle, which mechanically reduces the conduction of sound from the ear drum to the cochlea (inner ear). Low frequencies trigger the reflex, high frequencies do not, so when you filter out the LF from your music, you remove the trigger for the reflex and actually allow more HF sound into the inner ear. So while the actual measured SPL is lower, the HF energy making it to the inner ear is higher.
Logged

Josh Ricci

  • Newbie
  • *
  • Offline Offline
  • Posts: 28
    • Data-Bass
Re: What does an simple SPL number tell you anyway?
« Reply #15 on: June 05, 2017, 10:30:14 am »

This is not just perception. The ear has a reflex, the stapedius reflex, that responds to loud sounds by tensing the stapedius muscle, which mechanically reduces the conduction of sound from the ear drum to the cochlea (inner ear). Low frequencies trigger the reflex, high frequencies do not, so when you filter out the LF from your music, you remove the trigger for the reflex and actually allow more HF sound into the inner ear. So while the actual measured SPL is lower, the HF energy making it to the inner ear is higher.

Well...I have learned something new today. Thanks for posting this.  :)

Scott Bolt

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1478
Re: What does an simple SPL number tell you anyway?
« Reply #16 on: March 03, 2020, 08:04:37 pm »

I loved this thread.  I learned so much.  Ivan rocks!
Logged

Yoel Klein

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 55
Re: What does an simple SPL number tell you anyway?
« Reply #17 on: March 03, 2020, 10:20:13 pm »

I loved this thread.  I learned so much.  Ivan rocks!
Thanks Ivan, I love these knowledge and it makes so much sense.
There is one factor I noticed with Danley speakers, and I named it “The Danley Effect”. Lol..
Because when you hear a non Danley box at lets say 100db, you perceive it as loud and full of energy and your happy.  Now play a Danley box, same content, same level, and you will feel like its missing volume... and tend to gain in up more, but you will never feel this brick of sound surrounding your ears, only until you turn it up so loud that your head begins hurting, that is when you realize that your listening to 8x the volume..  and I think this is because the Danley sounds so refined and so clean, which allows your ears to tolerate a much much higher volume. 
Which I call this the Danley effect...
« Last Edit: March 03, 2020, 10:22:22 pm by Yoel Klein »
Logged

duane massey

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1613
Re: What does an simple SPL number tell you anyway?
« Reply #18 on: March 03, 2020, 10:56:12 pm »

Many years ago I attempted to come up with meaningful measurements on a cabinet we had been building for a number of years. Did some research on how JBL, Community, etc, did their measurements. Made as accurate a measurement as we could, and the numbers were somewhat disappointing. Went back and read the marketing literature from the "big boys" and realized that (a) they didn't talk about the actual measurements, just the +/- 10db readings and/or calculated peaks, and (b) none of our clients would ever read the specs anyway, as we typically sold our boxes by doing onsite demos. The numbers don't tell you how the box sounds. I build very few boxes now, and my back & knees are grateful.
Great post, Ivan, as always.
Logged
Duane Massey
Technician, musician, stubborn old guy
Houston, Texas

Mac Kerr

  • Old enough to know better
  • Administrator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6922
  • Audio Plumber
Re: What does an simple SPL number tell you anyway?
« Reply #19 on: March 03, 2020, 11:36:44 pm »

Amazing how a Russian troll posting to this thread before being discovered and removed has resurrected a 3 year old zombie.

Mac
Logged

ProSoundWeb Community

Re: What does an simple SPL number tell you anyway?
« Reply #19 on: March 03, 2020, 11:36:44 pm »


Pages: 1 [2] 3  All   Go Up
 



Page created in 0.061 seconds with 24 queries.