What SPL (dBz/flat) do you start to feel the subs? |
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toastyghost
The 10,000 Points Club Joined: 09 January 2007 Location: Manchester Status: Offline Points: 10920 |
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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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martinsson
Registered User Joined: 19 June 2007 Location: Sweden Status: Offline Points: 325 |
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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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Swedish Pro-fi diy-nerd - http://www.martinsson.cc/blog/
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fatfreddiescat
Young Croc Joined: 15 October 2010 Location: N.E.Wales Status: Offline Points: 1081 |
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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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KaphaSound
Registered User Joined: 22 July 2020 Status: Offline Points: 102 |
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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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toastyghost
The 10,000 Points Club Joined: 09 January 2007 Location: Manchester Status: Offline Points: 10920 |
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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.
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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Elliot Thompson
Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5172 |
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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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Elliot Thompson
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fatfreddiescat
Young Croc Joined: 15 October 2010 Location: N.E.Wales Status: Offline Points: 1081 |
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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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carlosdelondres
Registered User Joined: 21 June 2012 Location: London Status: Offline Points: 243 |
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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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Andylaser
Registered User Joined: 16 April 2010 Location: Southampton Status: Offline Points: 300 |
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Thats excellent. Thanks.
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"music so loud, that if we move in next door to you; your lawn will die" - Lemmy
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KaphaSound
Registered User Joined: 22 July 2020 Status: Offline Points: 102 |
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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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fat_brstd
Old Croc Joined: 23 August 2008 Location: Melbourne, OZ Status: Offline Points: 2125 |
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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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0krizia
Registered User Joined: 15 February 2016 Location: norway Status: Offline Points: 79 |
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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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