[Anthony_Gomez]

A bit ago, I was chatting with Matt and this topic was hit on a bit. It also seems to be an active topic in a couple other threads. I thought I'd bring about the question here and see if we can get an interesting discussion, and hopefully measurements on this topic.



The thought game is this: If you take the new Fusion-6, Tux-1099, and Sentinel and calibrate them all to 75db pink noise and EQ to a flat response, and then do an impulse response with each of these (100 Hz to 250 hz) at +20 db, how would they compare? By impulse, I mean something like gun fire or bass drum: loud, and quick in transient..the thump in your chest midbass. In theory, you may say that if they all have the exact same frequency response, and are all calibrated to play the same intensity, they should sound identical....but they won't.


In practice, how does Bl and thermal compression through VC heating come in to play? If you send a +20 db signal to each of those speakers, what do you actually get (this is where measurements, not theory come in to play. I don't have the means to do so, but one of you may). Vd is not the same for all the woofers, and the smaller ones need more travel, extending further down the Bl curve where efficiency drops. Likewise, thermal non-linearities in the coil will suppress excursion.


...how much midbass punch would each of these woofers lose to these effects? If you put in +20 db, does the sentinel produce +19 db, the tux-1099 produce +17 and the karma-6 produce +15? (I made those numbers up).



/discuss

 

[Anthony_Gomez]

Here is some additional reading material

http://sound.westhost.com/articles/pwr-vs-eff.htm

 

[BassThatHz]

I've never heard two speakers or amps that have ever sounded the same. But that could just be me (I've never subjected myself to a blind shootout).


That said, I wouldn't be able to tell you which field the wine was in made or the types of grapes used, but I could tell you the difference between wine and grape soda or cola. LOL

I would expect the one with the highest combination of power handling, highest sensitivity and beefiest woofer config, to make the loudest bass and upper bass, beyond that, all else being equal, it shouldn't be "vastly" different. +-5db say.

(Assuming the crossover and box isn't doing something funky or special.)


My 2 cents.

 

[Anthony_Gomez]

I think you completely missed the message :-D

 

[Bill Fitzmaurice]



Quote:
Originally Posted by Anthony_Gomez  /t/1521760/midbass-punch-spl-voice-coil-heating-and-bl-linearity#post_24460176


.how much midbass punch would each of these woofers loose to these effects?

Hard to say without data. Some manufacturers do put power compression charts on their data sheets, Beyma is one.

 

[eXa]

This is intereresting, will follow

 

[michael hurd]

Sound on Sound did an article on just this quite a while ago, I will see if I can dig it up.

 

[michael hurd]

Here's the article entitled Monitors vs HiFi speakers.

http://www.soundonsound.com/sos/Jul02/articles/monitors2.asp

 

[Anthony_Gomez]

Thanks. I'll give it a read. The link I posted earlier is a solid read and hope this is too

 

[CZ Eddie]

Midbass punch/slam/kick.

There is a bit of magic to it I suppose.

From research I've done on the subject, you will get this tactile feel mostly between 50hz to 200hz. Though even tweeters can give a punchy sort of feel.

For a midbass driver, my research shows that you want a light cone. And a QTS below .50, QMS that is higher than not and a low FS.


Four of the Dayton DA175 8" midranges per side are said to provide excellent midbass punch. Even though the parameters don't really match up with what I suggested above.
http://www.parts-express.com/dayton-audio-da175-8-7-aluminum-cone-woofer--295-335

edit: I think I missed the point of the thread also. Sorry. I'm too sick ATM to really pay attention to what I'm reading.

 

[Okv]



Quote:
Originally Posted by michael hurd  /t/1521760/midbass-punch-spl-voice-coil-heating-and-bl-linearity#post_24460685


Here's the article entitled Monitors vs HiFi speakers.

http://www.soundonsound.com/sos/Jul02/articles/monitors2.asp

The problem is that they focus on the wrong parameters.

Thermal effects will affect macro-dynamics - louder passages will eventually sound less loud when the vc heats up.

Transients, which is what the physical impact is about, is not much affected by thermal properties because the effects have a relatively long time constant compared to the duration of the transient.


What is a very significant parameter is compression due to limited output capacity.

These bookshelf-speakers are really not even suited as satellite speakers if you want to play music at a realistic spl.

If you look at the pictures, you see a range of what is more or less the same - small speaker with small woofer.

Regardless of what is claimed these can never play loud with realistic impact.


I did some measurements when playing music at different levels, and this shows that transient peaks are often 30dB above measured rms level.

(Article with measurements and very nice graphs on my blog.)


That means you would need 110dB capacity to play 80dB.

Do you think a 8" woofer can do 110dB down to, say, 80Hz?

Not even close..


Some time ago, all studios had real speakers with 15" or bigger woofers, think JBL 4350 and alikes - speakers that has great output headroom, but there is more to it - they also had what can be called dynamics.

Then someone got the idea that you can use a small plastic box with tiny woofers instead, and now all studios have these bookshelves they call "near-field-monitor".


This is one of the reasons why todays music is totally devoid of real impact and slam - the microdynamics of the music - how loud a single transient is compared to the simultaneous rms level.

 

[wvu80]

I'm going to try to keep up with the Smart Guys in this discussion, but with change of weather has brought me a massive head cold, and I'm finding it hard to think critically and deeply right now.


I think the topic is interesting, but flawed because of all the other variables, in particular electronics and the "listening modes" of most modern AVR's. Unless you simply compare a single speaker A vs a single speaker B with almost no electronics in between, I don't see how a reasonable conclusion can be reached.


In addition, what is being compared is charts and graphs against each other. Someone please correct me if I'm wrong, but no matter how the charts and graphs are made, there isn't a chart or graph which can give you SOUND QUALITY, ie, does a piano really sound like a piano when played through speaker X (X, the unknown).


To me, there are two basic types of speakers; those that sound good, and those that are accurate. They are not necessarily the same thing.

 

[wvu80]



Quote:
Originally Posted by Okv  /t/1521760/midbass-punch-spl-voice-coil-heating-and-bl-linearity/0_50#post_24461116


The problem is that they focus on the wrong parameters.

Thermal effects will affect macro-dynamics - louder passages will eventually sound less loud when the vc heats up.

Transients, which is what the physical impact is about, is not much affected by thermal properties because the effects have a relatively long time constant compared to the duration of the transient.


(respectful SNIP!)


This is one of the reasons why todays music is totally devoid of real impact and slam - the microdynamics of the music - how loud a single transient is compared to the simultaneous rms level.

I highlighted "todays music" because I think you are 100% right. Good music, to me, has dynamics in it. I'm not sure I hear any dynamics at all in music played on the radio (which I rarely listen to), and the little bit you do hear is heavily compressed. You almost always hear dynamics in symphonic music, some in jazz, but almost none in pop or rock music.

 

[Anthony_Gomez]

wvu80, while both those posts have interesting points, they fall well outside the scope of the OP

 

[Ivan Beaver]



Quote:
Originally Posted by wvu80  /t/1521760/midbass-punch-spl-voice-coil-heating-and-bl-linearity#post_24461419


I highlighted "todays music" because I think you are 100% right. Good music, to me, has dynamics in it. I'm not sure I hear any dynamics at all in music played on the radio (which I rarely listen to), and the little bit you do hear is heavily compressed. You almost always hear dynamics in symphonic music, some in jazz, but almost none in pop or rock music.

What is "todays music"?


Is it pop rock? in which "loudness" seems to most important

What about EDM? The most growing segment of music


Is it country? Which is basically 70s southern rock


Is it rap?

 

[tuxedocivic]

Anthony, are you thinking outdoors, or in a typical ht? If in a HT with reflections, mid bass performance is heavily influenced by the room, which means it'll be heavily influenced by the amount of eq required. For instance, if the smaller speaker only requires 1db boost at 150hz whereas the sentinel requires 20db (major exaggeration) then I'd put my money on the Fusion 6 actually.


Having said that, if we don't consider the room, then we should revise the scope to say the anechoic responses are eq'd the same. In that case, these are the subjective differences I would expect.


The smaller speaker's mid bass will sound more punchy, but have less impact. Yes, more punchy. This is cause the upper range will dominate, AND some harmonic distortion will contribute. HD is higher in frequency which have kind of a smack/punch sound.


The larger more capable woofers are going to sound more natural and easy going. Eq'd the same they may even sound a little unimpressive. The little woofer will have that "oh wow that's a lot of sound from such a tiny thing" kind of effect but the big woofer is going to be doing the job with ease meaning it'll sound clear and natural without strain.


Ok, so I don't actually have any personally done power compression measurements for any woofers handy, just dome tweeters. Based on that experience the HD does increase at the lower end of the drivers pass band, contributing to greater overall output. Yes, the tweeters I've measure out out MORE sound at high SPL in the lower ranges. This is why I said the small woofer will actually impress at first. The problem is, the added sound is all garbage and shouldn't be had.


I haven't personally done klippel measurements, but the ones I've seen have always showed a roll off of BL at the limits of excursion. So its safe to infer that the woofer would play the higher frequencies in accurately while excursion is at the limits while playing loud mid bass.


Finally. The bigger woofers have larger voice coils, therefore its safe to infer that they would keep their voice coil temperature more evenly regulated, thus more uniform mid bass output during long and loud listening sessions. Two woofers means two voice coils which is a significant advantage there.

 

[CZ Eddie]

Bose 901 series speakers. Filled with ten 4" full-range drivers.... gave some nice dynamics.
http://www.stereophile.com/standloudspeakers/425/


My next speaker build will be filled with several small midbass speakers rather than one large 12" or 15".

 

[Okv]

I am sorry about the OT music-comment, I think my point also was lost somewhere because of that.


So, what can, and what can not cause differences in midbass punch, when looking at bass driver properties only.


Thermal issues are not significant because of the too long time constants involved.

The "punch" lasts only a few milliseconds, it takes in the order of seconds to heat or coll the voice coil.


Bl and excursion limits is what limits the output, for a given radiating cone area.

Longer excursion before Bl is lost equals more punch.

More cone area equals more punch.


To reproduce a transient signal there must be sufficient spl capacity to reproduce the full amplitude of the original signal.

If, say, 3db is lost, there is a loss of punch.

This is not something that one necessarily can hear as distortion, because it happens in a very short time interval.


The attached picture shows the waveform of music with a drum hit.

The upper graph is the original, directly from the source.

The lower graph is recorded at the listening position using a microphone.

The signals are clearly different, but in this case one can recognize the shape of the original drum hit in the recorded signal.

That is also how it sounds - or, rather, it doesn't sound, it just hits.

If the top of the impulse is cut off, there will be no impact but it will not necessarily sound bad or wrong.

 

[wvu80]



Quote:
Originally Posted by Anthony_Gomez  /t/1521760/midbass-punch-spl-voice-coil-heating-and-bl-linearity/0_50#post_24461449


wvu80, while both those posts have interesting points, they fall well outside the scope of the OP

I apologize, I was wondering if I had mis-understood what the OP was asking. I had been pondering the sound quality issues recently. I guess I just rolled my ideas into the closest thread.

Thank you for straightening me out. "He who corrects my mistake giveth me a gold coin."

 

[wvu80]



Quote:
Originally Posted by Ivan Beaver  /t/1521760/midbass-punch-spl-voice-coil-heating-and-bl-linearity/0_50#post_24461460

What is "todays music"?


Is it pop rock? in which "loudness" seems to most important

What about EDM? The most growing segment of music


Is it country? Which is basically 70s southern rock


Is it rap?

Hah! Thanks for me calling me on that, as you are right, of course.

Country music really is pretty good music, good vocals, good arrangements, I'm just not a big fan. Not a fan of EDM (I'm old enough to remember and have hated disco), no rap, no dub step, no grunge, no hip hop, and NO Justin Bieber!


Since I am old, I therefore define "modern music" as anything later than the 60-70's rock, not jazz and not classical.

(there really is some good modern symphonic music, Bernstein, Copeland, John Williams, Zimmer, movie theme types of things)