On the issue of avg loudness and crest factor...
My own design target is for the system to be able to deliver an 85dB average level at the listening position (i.e., at approx 3m from each loudspeaker), while allowing for a 20dB crest factor (i.e., 105dB peak at the listening position) without any measurable compression.
Incidentally, 85dB average with 20dB crest factor is also the recommended cinema industry standard.
YMMV.
Marco
My own design target is for the system to be able to deliver an 85dB average level at the listening position (i.e., at approx 3m from each loudspeaker), while allowing for a 20dB crest factor (i.e., 105dB peak at the listening position) without any measurable compression.
Incidentally, 85dB average with 20dB crest factor is also the recommended cinema industry standard.
YMMV.
Marco
Q values subscripts are for “total system” and “mechanical system’ is the way I interpret it... Fs and Fc just don’t sink in.
[emoji16][emoji16][emoji16]. Normally I think the term Le is used? The whole thing is quite confusing at times because sometimes we talk about measures values, then equivalent values are used quite often. Just a few days ago I was measuring the voice coil inductance alone, sticking a core in the middle, and then outing a copper tube around the core looking at the values changing. Quite interesting.
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The 'system' interpretation makes no sense since Qts only refers to the speaker while the total system Q (ie speaker in box) is Qtc.
Qts would include the mechanical system “ms” and the electrical system “es”. This is the way I read it.
Don't know, don't care as long as I remember that it denotes the Q of a speaker in a box.
Much easier just to learn the terms rather than trying to second guess what each letter actually stands for. Avoids confusion like yours. ;-)
Piano in room reference for dynamic range
For dynamic range I suggest using an "un-plugged" reference, a piano in a room.
In my rural location I have low ambient noise in my listening room, around 30dB to 35dB on an average day.
Measuring a piano with an Earthworks Mic at 2 meters, the SPL's vary from a few dB above ambient to 107dB... Trumpet can be 112dB at 1 meter!
So the entire recording / playback chain must be able to maintain a minimum of 82dB dynamic headroom in order not "clip" the sound.
Even when playing gently, live instruments regularly hit 50 dB peaks over ambient.
Failure to reproduce life like dynamics is one of the most common failings in domestic audio equipment.
Poor / very poor time domain performance is the most common failing.
Addressing the dynamics issue can go along way to addressing the time domain issue as well. The loudspeakers are the weakest link in both areas.
Hope this helps and all the best
Derek.
Custom Install Audio | Advanced audio equipment
For dynamic range I suggest using an "un-plugged" reference, a piano in a room.
In my rural location I have low ambient noise in my listening room, around 30dB to 35dB on an average day.
Measuring a piano with an Earthworks Mic at 2 meters, the SPL's vary from a few dB above ambient to 107dB... Trumpet can be 112dB at 1 meter!
So the entire recording / playback chain must be able to maintain a minimum of 82dB dynamic headroom in order not "clip" the sound.
Even when playing gently, live instruments regularly hit 50 dB peaks over ambient.
Failure to reproduce life like dynamics is one of the most common failings in domestic audio equipment.
Poor / very poor time domain performance is the most common failing.
Addressing the dynamics issue can go along way to addressing the time domain issue as well. The loudspeakers are the weakest link in both areas.
Hope this helps and all the best
Derek.
Custom Install Audio | Advanced audio equipment
When we study controls systems, any device can be a system by itself. So we are used to reading out the subscripts into exact words. Since the speaker driver consists of mechanical properties and electrical properties, we are used to referring to each part as “system”, then you get the total driver system “ts”. This is totally reasonable to me.
I agree with the piano example. Have not totally figured the solution out yet, but in the process of doing so.
In hat case what did you think the s in Qms and Qes stands for since you just explained that in your view it only becomes a 'system' when both are combined into Qts?
Either way don't you think it makes more sense just find out what these denote as used by everybody rather than just sticking with your interpretation which may or may not be correct?
It is fine if I were only involved with audio, but since I deal with multiple technology, it is important to understand exactly what each means. I never could just memorize blindly.
Isn't the dynamic headroom of music recordings closer 60 dB at best?
I ask because in reality we do not reproduce live piano but recordings.
what kind of room? Normally a pianist adjusts dynamics not only to the ambient noise but to the volume and acoustic liveliness of the room as well
Extreme example to illustrate my point - imagine playing piano in a tiled bathroom
The topic had been discussed here: SPL targets for speaker design