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What SPL (dBz/flat) do you start to feel the subs?

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toastyghost View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 20 April 2021 at 10:46am
Originally posted by KaphaSound KaphaSound wrote:

Wow thank you toastyghost! This is exactly the kind of thing I’m looking for and to top it all off it’s even in dBz by frequency. I know AES have tons of papers but this one strikes me as one of the more interesting (alteast personally). I have actually done some research into body resonances which show some interesting results as far as where you may predominantly feel certain frequencies and how your build may affect this, but the threshold was never particularly clear.

From the abstract: “<span style="caret-color: rgb77, 77, 77; color: rgb77, 77, 77; font-family: "Roboto Condensed", sans-serif; font-size: 17px; -webkit-tap-highlight-color: rgba0, 0, 0, 0; -webkit-text-size-adjust: 100%;"> Perceptual tests identified a frequency dependent threshold of 94-107dBZ required to induce a perceivable whole-body vibration.</span>” I don’t think the answer gets more clear than that so again thank you! Just a few follow up questions: I’m assuming the black lines in the grey bars are the variations between subjective results? So what is the black line graph since it doesn’t look like an average of the grey bar trend? And is the acceleration measurement a result of both frequency and spl (apologies if this is a basic question)?



My guess based on this info is that ~130dbz should be enough for a physical experience over a space big enough for 50-200 people or so. I am hoping these horns will actually be able to hit 140 continuous down to about 32hz in groups of 4, but I’ll have to take measurements to confirm.





No worries, but if you can't find other interesting things on there, you aren't trying hard enough

You might like this one, for example... https://www.aes.org/e-lib/browse.cfm?elib=19179

The black line on the first graph is for the right axis, which is the vibration threshold, the whiskers belong to that to show the range of data points in that 'bin'. The bars are for the left axis.

You might be surprised what real-world continuous output is for subs, especially with modern music. You're going to be thermally limited with a FLH. Consider the temperature rise. MEASURE IT if you can. Look up the toaster test.

This is one of those places where the old school don't really seem to 'get' how modern subs using low tunings/big ports with high BL drivers and Class D amps work in tandem to produce much more consistent results at low and high drive levels.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote martinsson Quote  Post ReplyReply Direct Link To This Post Posted: 20 April 2021 at 3:57pm
True, yet somehow I can't let go of my perception (note the wording) that your average large format linearray with the standard ~30Hz tuned 218 BR sub complement just does not seem to have the same impact in the 80-120Hz range, sure there is sub, loads of it even, but I perceive it to lack kick and definition bass range compared to "old school" flh and horn setups, stay turbosound flashlight for example.

Some of this is down to frequency content but not all I believe.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote fatfreddiescat Quote  Post ReplyReply Direct Link To This Post Posted: 20 April 2021 at 5:26pm
Originally posted by martinsson martinsson wrote:

True, yet somehow I can't let go of my perception (note the wording) that your average large format linearray with the standard ~30Hz tuned 218 BR sub complement just does not seem to have the same impact in the 80-120Hz range, sure there is sub, loads of it even, but I perceive it to lack kick and definition bass range compared to "old school" flh and horn setups, stay turbosound flashlight for example.

Some of this is down to frequency content but not all I believe.

Possibly due to the 80Hz area being the typical crossover region, usually using 4th order slopes and non linear phase due to the delay that would be incurred if using linear phase filters. A 4th order filter would mean the lows are a full cycle behind the high's and likely a non perfect cancellation of the filters 'ringing'?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KaphaSound Quote  Post ReplyReply Direct Link To This Post Posted: 20 April 2021 at 5:29pm
Thermal limitations are definitely a concern of mine with a FLH considering no ventilation for the rear chamber, however in all the sims I’ve run I’m hitting xmax/xvar at about a 1/4 of the driver’s peak power rating, meaning I’d be running continuous at even less than that (200-400watts into 8ohm) so I’m hoping the sheer efficiency essentially prevents thermal compression from having a big influence on output.

That second paper is also very interesting and backs the idea that more bass could actually reduce the preferred total dBa volume level. I certainly intend on trying to push the limits here as far as running the mid tops low say ~90-95 and the subs closer to 120-130. Thanks again toastyghost!


Edited by KaphaSound - 20 April 2021 at 7:56pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 20 April 2021 at 9:52pm
Originally posted by fatfreddiescat fatfreddiescat wrote:

True, yet somehow I can't let go of my perception (note the wording) that your average large format linearray with the standard ~30Hz tuned 218 BR sub complement just does not seem to have the same impact in the 80-120Hz range, sure there is sub, loads of it even, but I perceive it to lack kick and definition bass range compared to "old school" flh and horn setups, stay turbosound flashlight for example.

Some of this is down to frequency content but not all I believe.



There are many more significant factors to tonal quality than frequency response. Horns are acoustic impedance matching devices. All of them, to varying degrees. Start your investigation there - warning, maths ahead.

Originally posted by martinsson martinsson wrote:

Possibly due to the 80Hz area being the typical crossover region, usually using 4th order slopes and non linear phase due to the delay that would be incurred if using linear phase filters. A 4th order filter would mean the lows are a full cycle behind the high's and likely a non perfect cancellation of the filters 'ringing'?


That’s a non-issue, even if your intuition was correct. Delay is commonplace, as are allpass filters. If your subs are a lap behind, then you fire your system tech.

Although I see that far more often than I would like. Another area where I’m fairly sure this comes down to people repeating what they’ve seen someone else do, rather than doing some maths and checking things over.

Edited by toastyghost - 20 April 2021 at 9:55pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 20 April 2021 at 10:09pm
Originally posted by martinsson martinsson wrote:

True, yet somehow I can't let go of my perception (note the wording) that your average large format linearray with the standard ~30Hz tuned 218 BR sub complement just does not seem to have the same impact in the 80-120Hz range, sure there is sub, loads of it even, but I perceive it to lack kick and definition bass range compared to "old school" flh and horn setups, stay turbosound flashlight for example.

Some of this is down to frequency content but not all I believe.


There are lots of reasons behind this. Here are few. Folded Horns of that era were bass bins in which, were good to around 60 Hz. Also, drivers were more efficient when you compare woofers designed solely for horn-loading from that era to today.


In the Philippines, Cerwin Vega copies are in abundance. Their set-ups offer a very strong punchy/impactful Bass (Nothing below 60 Hz). The video below shows what you can achieve playing 60 Hz - 180 Hz from a large stack of horn-loaded Bass Bins.



The Sound Systems in the Philippines generally build their own amplifiers in addition to, design their own woofers.

Having a good understanding of your music content will steer you in the direction of Horns or Reflex.


Best Regards,






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Post Options Post Options   Thanks (0) Thanks(0)   Quote fatfreddiescat Quote  Post ReplyReply Direct Link To This Post Posted: 20 April 2021 at 11:32pm
Originally posted by toastyghost toastyghost wrote:

Originally posted by fatfreddiescat fatfreddiescat wrote:

True, yet somehow I can't let go of my perception (note the wording) that your average large format linearray with the standard ~30Hz tuned 218 BR sub complement just does not seem to have the same impact in the 80-120Hz range, sure there is sub, loads of it even, but I perceive it to lack kick and definition bass range compared to "old school" flh and horn setups, stay turbosound flashlight for example.

Some of this is down to frequency content but not all I believe.



There are many more significant factors to tonal quality than frequency response. Horns are acoustic impedance matching devices. All of them, to varying degrees. Start your investigation there - warning, maths ahead.

Originally posted by martinsson martinsson wrote:

Possibly due to the 80Hz area being the typical crossover region, usually using 4th order slopes and non linear phase due to the delay that would be incurred if using linear phase filters. A 4th order filter would mean the lows are a full cycle behind the high's and likely a non perfect cancellation of the filters 'ringing'?


That’s a non-issue, even if your intuition was correct. Delay is commonplace, as are allpass filters. If your subs are a lap behind, then you fire your system tech.

Although I see that far more often than I would like. Another area where I’m fairly sure this comes down to people repeating what they’ve seen someone else do, rather than doing some maths and checking things over.

Somehow the quotes are back to front! Re 360 degree lag for the lows, for 4th order it is a 12.5ms delay to adjust for, fine if that is acceptable to add to the system latency, then I agree that allpass and delay would work, there are other IIR alternatives as I'm sure your aware. There have been many discussions about the difference between how horn loaded systems thump like nothing else, other than roll off slopes and the use of crossovers in the 'kick' area is that power factor in acoustical terms may play a part? Bummer that Bowlers didn't come off last Feb as I was booked for one of the other rooms and was hoping to hook up.

Edit: also meant to mention transient response.


Edited by fatfreddiescat - 21 April 2021 at 7:33am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote carlosdelondres Quote  Post ReplyReply Direct Link To This Post Posted: 11 May 2021 at 1:52pm
Interesting thread :)

Any thoughts on the pulse quickeing effect of certain alignments?

I've spent most time listening to boxes I've owned/build, and from terrahorns, SS15 tapped horns, 2x18 BPH and others, a pair of dual 5" (really) PPSL ported plenum 6th order bandpass boxes have a definite pulse racing effect, even though they don't go much below 50hz or over about 110dB.

It's quite an 'exciting' effect, though those boxes are maybe a little fatiguing on the ear after an hour or two. Almost heart racing stage fright type anxiety. Not the same as kick chest compression, more a psycho acoustic effect I thought especially given the low level of the output.

Any thoughts on this and how it might contribute to the urgency/physicality of bass reproduction?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Andylaser Quote  Post ReplyReply Direct Link To This Post Posted: 12 May 2021 at 1:28am
"music so loud, that if we move in next door to you; your lawn will die" - Lemmy
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KaphaSound Quote  Post ReplyReply Direct Link To This Post Posted: 12 May 2021 at 3:24am
Originally posted by carlosdelondres carlosdelondres wrote:

I've spent most time listening to boxes I've owned/build, and from terrahorns, SS15 tapped horns, 2x18 BPH and others, a pair of dual 5" (really) PPSL ported plenum 6th order bandpass boxes have a definite pulse racing effect, even though they don't go much below 50hz or over about 110dB.

It's quite an 'exciting' effect, though those boxes are maybe a little fatiguing on the ear after an hour or two. Almost heart racing stage fright type anxiety. Not the same as kick chest compression, more a psycho acoustic effect I thought especially given the low level of the output.

Any thoughts on this and how it might contribute to the urgency/physicality of bass reproduction?

I believe this comes down to group delay. Sealed/open baffle will always be the fastest from what I gather but that’s not usually going to efficiently get loud enough for an intense physical sensation. Ported seemingly always has a fair bit of group delay at tuning, and horns seem to be the most variable with group delay also gradually increasing around tuning. More group delay gives you a more sluggish response which I believe is what you mean by the pulse effect, but there is certainly a debate around how much is perceptible especially in the 30hz range and below.


Edited by KaphaSound - 12 May 2021 at 3:25am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote fat_brstd Quote  Post ReplyReply Direct Link To This Post Posted: 12 May 2021 at 4:49am
Originally posted by toastyghost toastyghost wrote:

This paper answers your question, for both dBZ SPL (at the listener) in 1/3rd octave bands, and how that translates to physical acceleration for those same frequencies.

https://www.aes.org/e-lib/browse.cfm?elib=20383

The terms you need to use are Whole Body Vibration; it’s different for each person as we all have an individual Body Related Transfer Function. It doesn’t seem to matter if you’re fat or not.

I noticed you mentioned trying to convert sound pressure to physical measurements. That’s not difficult, sound is often measured or calculated in Pascals and converted.

They had 28 test subjects who were fitted with six accelerometers, at key points for conduction like the chest and shoulders. It’s a bloody good paper, frankly. They only used a single dual 18” French sub but that’s absolutely fine in the test environment used.

Here are the juicy bits:




Be aware these are taken out of context before you throw judgement! If you haven’t read the methodology and prior research, then you may find it hard to put aside your subconscious bias.

I won’t share the full paper, but if you’re really serious about answering these sorts of questions then the AES journals are a damn good place to start looking. Even if you don’t get everything that’s being discussed, you then have jumping off points for more research and reading, or to ask more specific questions. It isn’t ‘cheap’ but I found I got my money’s worth very quickly. Not just on journal access, but the several meets and education sessions every month.

As an aside I’m often quite shocked how many supposedly professional ‘engineers’ don’t seem to want to spend the very reasonable annual AES membership fee. I guess it doesn’t fit with the stereotype of repeating the same old waffle in a grumpy manner? 😅

If you’re a student, it’s damn cheap and takes 5 years to hit full price. Take advantage of that situation if you can!


So 63hz-75hz is really where the sweet spot is in terms on shaking the audience, no wonder the reggae boys love the scoops so much
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 0krizia Quote  Post ReplyReply Direct Link To This Post Posted: 13 May 2021 at 4:47pm
The lower the frequency, the more physical the sound is.
 
correct me if im wrong...
Most sound engineers tend to aim for a sound signature with a gradual increase in spl the lower the frequency is in the bass region. I have spoken to multiple sound engineers on concerts I have been on and most in Norway tend to aim for an average of 100db above 100hz at their location during the concert. Add the typical 10-15db boost at the lowest frequencies many engineers apply and we are at 110 -115 db, by being 4 times closer to the stage than the sound engineer, the spl increase with an additional 12 db, add an additional 6db for dynamic range and the level is 128-133 in the bass and sub region. At this level, it can definitly be felt. The challenge is to achive this level of soundpresure between 30-38hz, it demands a serious system.
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