salas said:
please treat my above response to Gedlee's comment accordingly i.e. as a response for You as well
thanks for Your kind responses! 🙂
best,
graaf
graaf said:
My rooms are actually quite "live" as I prefer that.
What you say is certainly true. But based on my experience people tend to grossly underestimate the need for high output. In Home Theater this is certainly true. None of the home theaters that I have seen (besides the ones that I did) had adequite sound capability for a quality experience. The video was always very good (why is that?). When I try to explain to people why I think it is that the sound is lacking the discussion always stumbles on the SPL requirements, as it did here.
If there is something that I would like you and others to take away from this it's that the requirements for SPL for good sound quality are propably much higher than you think they are. The result is that the ever present 6 - 8" woofer and dome tweeter are not going to get there. They lack efficiency and power handling capability, the combination of which dramatically reduces the Max SPL capability. And this, to me, spells trouble. Not always, but enough that I would never look at these components for any of my designs.
It used to be that high SPL and good sound quality were not compatible and so the High SPL designs got a bad name. Today they are compatible and there is no justification not to go for both.
Hi, have you got a reference for that? I'd like to read it.
I think the problem with a lower SPL as a specification is headroom, as has been mentioned here several times.
I like to listen to opera and other "big music" and the loud parts are indeed very loud, from a subjective point of view, whether at home or in the the theatre.
Clean sound at high levels from speakers is a necessity for me. Gotta have the headroom.
Because of the dramatic emphasis in my listening material, I think my requirements are more like those for HT than "ordinary" HiFi.
gedlee said:
That rang a bell. In bar / club installations we used to ask the sales guy: How loud they said they work? OK. We will shoot for double. Try a bigger budget!
If we could not pass that, we always had burned voice coils every now and then, and complaints for bad, not enough sound.
If the salesman cant originally up the customer's budget and they maintain that they know what is enough for them blah blah, they will not only blame the salesman in a while, but they will go to another company too!
salas said:
Lets face it, the salesman has an incentive to low ball the SPL requirements. They want the sale and burned out drivers is another sale. Warrantees are a help, but its the customer thats paying for them in the end. The key, again based on experience, is to go for the upper edge of the SPL guess. Anything else just seems to lead to trouble.
gedlee said:
Again, I'm with you fellas- I like big, high output speakers. But there's a place for smaller speakers. Smaller rooms, different environments.
And there's a big disconnect on what constitutes 'loud'. To me, I want fairly realistic acoustical instrument levels. Amplified music levels are always too high at the venue, and this is bothersome, and uncomfortable to me. You say you can listen at 110dB average level. Not me mate, that's just painful.
I think also that you're underestimating hearing loss potential at those levels. If it makes your ears ring, and I think most people would experience that at 110dB average, that's too much volume.
To that end, perhaps having distortion set in a little earlier is a good thing. It warns you to turn the thing down. When you have a few drinks in you..... well, your hearing mechanism doesn't protect itself as well, and one tends to wick up the volume. Without any safety limits on how loud you can go....
AND! Let's not forget: Neighbors. Most of us have them, and 110dB is too loud to be courteous to your neighbors (assuming 'typical' proximity), unless you have a soundproof room.
There's some design flexibility that leaving 10 or more dB off the table gives you, too. Broader transducer selection, amp choices, more flexibility in cabinet design and alignment, lighter, smaller speakers that may be able to be better placed within the domestic constraints.
It's not 'all or nothing' folks, there's a reason there's so much diversity in audio. It's ultimately subjective. I get undistorted peaks at the levels I listen at, that's enough for me, as it should be for any of you. What level that is is up to you, but careful with your ears, you only get 1 set.
badman said:
I thought that we put to rest the hearing damage issue. At 110 dB, and I've done that fairly often, my ears don't ring afterwords. Ringing a sure clue to damage. Now a table saw or router - if I am too lazy to get the protectors - that will make my ears ring. Music is just NOT the kind of signal that lends itself to damage unless you are a pro and in those levels a lot.
Alcohol does not change the ears protective mechanisms, it just lowers your sensitivity to them - you don't care!
Let us (we loud ones) recap:
We said that we really need 115dB at 1m per stereo speaker capability, so to have absolutely clean 100dB peaks at 3m in home. Also that gives us 110 dB max peak headroom at 3m, so to occasionally 'party' with not that bad distortion.
We said that we really need 115dB at 1m per stereo speaker capability, so to have absolutely clean 100dB peaks at 3m in home. Also that gives us 110 dB max peak headroom at 3m, so to occasionally 'party' with not that bad distortion.
Please don't forget that the sensitivity to high spl's depends on the frequency. Continuous levels of 110dB at 2.5-3kHz will cause ringing and damage to the hearing apparatus while we may tolerate it well down at 50Hz. The threshold of pain may differ 20-30dB between bass and upper midrange tones.
/Peter
/Peter
FrankWW said:
here You are: http://www.soundstagemagazine.com/measurements/test_loudspeakers.htm
NRC is known for comprehensive research on the acoustics and psychoacoustics of sound reproduction
I believe that it is the only public research institution involved in a government-sponsored serious scientific research on "HiFi issues"
the head of audio research at NRC was Dr. Floyd Toole
here is an interesting short review with Dr. Toole: http://www.sonicdesign.se/tooleinw.htm
some remarks from Mr Moulton:
http://www.moultonlabs.com/more/some_reminiscing/P1/
http://www.moultonlabs.com/more/speaker_speaker_on_the_wall/P2/
"Know Your Tooles" 😉
best,
graaf
gedlee said:
I've always heard that alcohol does affect the hearing mechanism. Linked is a reference: Yeah. That's right. A reference. You got a problem with that?
Pretty simple, it changes perceptive thresholds. Accordingly, you're using 15dB (=/-7dB, imagine if it were 22dB!!) more juice when you're drinking, if their study is correct. Surely we agree that 15dB covers enough range to span between safe and unsafe levels
Dr. Geddes, I think you're applying your own experience and preference universally here. I think most people would find 110dB average levels to be uncomfortably loud. If you and others don't, that's fine, but be careful here, the solutions you've found to be optimal for your listening aren't inherently applicable to all listeners.
Preference and individual ears define what's necessary here. Plenty of people are happy listening at much more modest levels than you've laid out, and I don't think that invalidates their speakers as possibly high-quality- it just means they're not necessarily high quality at high level.
Most of my listening is done at levels with about 80dB average. I've built plenty of speakers, and while my trend is towards big, dynamically unrestrained designs, there's plenty to be said for much smaller speakers, when you don't need the output.
These have cast aluminum spherical enclosures and 4.5" (FR125) full range drivers. The enclosures would be very impractical and hugely expensive with enough drivers to achieve your target SPL, and the drivers obviously wouldn't be able to do it well either. But for the use, they're an extremely high quality solution. With very limited max SPL.
gedlee said:
Alcohol does affect all nervous activities. All sences and all motor functions are affected. The hearing protection depends on proper signal function of the motor nerves to m. tensor tympani and m. stapedius as well as the afferent sensory nerves leading signals from the peripheral nervous sytem to the central nervous system.
What you say and propose on this forum may lead to hearing damage and tinitus in people that doesn't know better and I feel that is very irresponsible.
/Peter
gedlee said:
10dB dynamic headroom may be enough for compressed rock and pop but not for carefully recorded and produced dynamic music. 20-30dB may be closer to what is needed for non compressed music.
/Peter
badman said:
I was talking about hearing damage not preference. Maybe 110 dB is too loud for you and others, fine, but for a typical music listening session of < 1 hour it will not damage your hearing. And thats not just experience thats OSHA and everyone else. I wouldn't recommend doing this every day, but once is awhile is fine.
gedlee said:
Try to listen to the Guru QM40 speaker when it hits the market in the US (maybe it did already?).
Well I think there have been such compatible designs for some time.
/Peter
perhaps a silly question, but I imagine a lot of the DIYers would have the kit, if not the knowledge, to do this.
There has been a lot of talk about 'clean uncompressed sound' at 1m, to allow for the peaks (of whatever desired level) at the listening position.
What I'd like to know (so I can see what my system does) is how do we measure those 'clean uncompressed sound' at the 1 meter reference? I mean if I do sweep say on the speakers, do I just gradually turn up the volume and continue taking sweeps? How do I recognise a 'clean uncompressed sound' from a graph, how do I see and determine the onset of compression? How do I determine the amount of compression.
Some of you must do it, as there has been talk of 'I designed for this target SPL performance' etc, how do we evaluate if thos targets have indeed been met?
Does the question make sense? (feel I'm stumbling to ask it clearly)
We want to have 10 db of available headroom to allow for the peaks. Surely there is a method that when done will allow all of us to say 'the SPL at which I have 10 db of available headroom left is X db', and the value of x will vary from system to system.
How do we determine x??
There has been a lot of talk about 'clean uncompressed sound' at 1m, to allow for the peaks (of whatever desired level) at the listening position.
What I'd like to know (so I can see what my system does) is how do we measure those 'clean uncompressed sound' at the 1 meter reference? I mean if I do sweep say on the speakers, do I just gradually turn up the volume and continue taking sweeps? How do I recognise a 'clean uncompressed sound' from a graph, how do I see and determine the onset of compression? How do I determine the amount of compression.
Some of you must do it, as there has been talk of 'I designed for this target SPL performance' etc, how do we evaluate if thos targets have indeed been met?
Does the question make sense? (feel I'm stumbling to ask it clearly)
We want to have 10 db of available headroom to allow for the peaks. Surely there is a method that when done will allow all of us to say 'the SPL at which I have 10 db of available headroom left is X db', and the value of x will vary from system to system.
How do we determine x??
Sure the it makes sense, a lot more sense than most of the posts her make, but there isn't a lot of agreement on what "it" is. I have done studies of thermal compression and I find that there are a lot of differences in poor sound systems and what I would call uncompressed or dynamic systems.
What I did was to blast the system with noise, at very high levels, and measure the frequency response as a function of time. This showed some systems changing a lot and other not so much. But there is no consensus on what the objective is. I think we would all agree that they shouldn't change at all, but none of them do that!
Buts lets not think for one minute that this is all there is to the story, because its not. Far more important IMO is the FR for the very early signal - the direct sound. This needs to be clean without a lot of interference, reflections, diffraction, etc.
Sound is a very multi-dimensional thing and we tend to talk only about single dimensions in any particuar thread. And sometimes we even talk about dimensions that have nohing to do with the problem. A lot of the time!!
I know that it can be tough to sort out what to do, but hang in there and maybe you can figure it out with the rest of us.
What I did was to blast the system with noise, at very high levels, and measure the frequency response as a function of time. This showed some systems changing a lot and other not so much. But there is no consensus on what the objective is. I think we would all agree that they shouldn't change at all, but none of them do that!
Buts lets not think for one minute that this is all there is to the story, because its not. Far more important IMO is the FR for the very early signal - the direct sound. This needs to be clean without a lot of interference, reflections, diffraction, etc.
Sound is a very multi-dimensional thing and we tend to talk only about single dimensions in any particuar thread. And sometimes we even talk about dimensions that have nohing to do with the problem. A lot of the time!!
I know that it can be tough to sort out what to do, but hang in there and maybe you can figure it out with the rest of us.
"Some of you must do it, as there has been talk of 'I designed for this target SPL performance' etc, how do we evaluate if thos targets have indeed been met?"
Hello terry
Pull out an SPL meter and see if you can hit your designed levels. For HT just throw on something with good effects and see what your numbers are. I was just messing with Cloverfield the other day. Had a couple of peaks that came in at 117db and 118db from the LFE and tank cannon effects. I wanted to be able to hit 115db so I would say I met my target. LFE is the one area I am limited. Nothing below 20hz and the LFE sub is right at it's excursion limit at those levels.
Rob 🙂
Hello terry
Pull out an SPL meter and see if you can hit your designed levels. For HT just throw on something with good effects and see what your numbers are. I was just messing with Cloverfield the other day. Had a couple of peaks that came in at 117db and 118db from the LFE and tank cannon effects. I wanted to be able to hit 115db so I would say I met my target. LFE is the one area I am limited. Nothing below 20hz and the LFE sub is right at it's excursion limit at those levels.
Rob 🙂
86dB + 160W + 108dB/1m in theory. Bit short of the original targets.Pan said:
http://www.guruproaudio.com/newguru/?page_id=10
Brett said:
but that is QM10
Pan was speaking of QM40, much bigger
nevertheless I doubt if the target set by Dr. Geddes can be indeed satisfied with anything else than what He recommends and what is a Pro-standard i.e. really big woofers and compression drivers
for 130 dB SPL peaks this is simply what is needed, nothing (read: almost nothing) else will do the job
best,
graaf
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