Voice coil diameter on woofers

[GM]

100% valid and good explanation. But I looked up resolution at all the available dictionaries. None applied to speaker bandwidth.
In fact the only audio definition had to do with digital amps.
IMHO if one wants to discuss bandwidth, lets do that.

From my viewpoint, if we want to use resolution applied to speakers, it would be how well a speaker reproduces (resolves) a complex waveform. Not trying to be an arse, but it's confusing to misapply words. Such as the 20 dollar speaker on eBay with an 8 inch "sub" and piezo.

Agree and understand and why I clarified what I thought was what he was referring to since thanks to the marketing chaps, 'resolution' is just one of several 'catch-all' terms that DIYers bring to the forums I mostly frequent to describe myriad performance parameters, so much of mine and others time is spent just figuring/finding out just what the @#$% the OP wants performance wise.

GM

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Doesn't articulate already already cover the discription, or would this be more snobspeak?

Again, the vast majority of folks that come to the forums haven't a clue how to speak in technical or at least in the correct layman's terms, though 'articulate' is an OK way to describe how accurately the system can reproduce the signal at high speech intelligibility through the telephone BW.

High fidelity/HIFI describes accurate musical reproduction at low distortion.

GM

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Theory and execution are also different animals.

So as a devil's advocate I'm going to state the design is more important than the voice coil size, which is what I stated before.

So Licorne, I state again, with good design good sound will be achieved regardless. Don't be too quick with the assumptions. As said many times, a little knowledge is a dangerous thing.

True, but this isn't theory, the VC is a pipe and pipe's have well defined acoustic properties same as a musical instrument's, so as I previously posted, any extra HF BW is designed in breakup modes, i.e. frequency modulation distortion, euphonic though it may be to human ears.

Hmm, as one devil's advocate to another , I'll restate it as 'a driver design is a collection of performance trade-offs to meet the needs of the app' since nowadays in many prosound apps the VC/motor design is paramount.

Agreed.

GM

[Old Guy]

I do appreciate your explanations GM, I always learn something from them. I think I really started learning about audio when I realized how much I didn't know.

But I think the OP might have walked away with the impression the larger coil will always have less HF response. As I said, loudspeaker engineering can't be reduced to a few sentences, though I have wished many times it could.

Let's postulate an aluminum wire 4 inch coil vs a heavier copper wire 3 inch coil. As you stated, the 4 inch coil is limited by its diameter. But a heavier smaller coil might not be able to reach the point where its diameter becomes a factor due to mass limiting...in this case the smaller coil might have less HF. And of course the rest of the speaker parts...

But yes, certainly, all other things being equal, the smaller coil should have a higher upper BW limit. But I didn't see any such disclaimer in the OP's conclusion.

[GM]

Glad I can occasionally 'peel back the veil of ignorance' as Tom Danley has opined.

Actually, mass doesn't affect woofer HF response ['speed'], just efficiency. I wish the old bass-list BBS? was available as me and a few 'unknowns' stirred up a hornet's nest that had some really sharp guys taking Tom Danley to task when he backed us up and even then it wasn't until he tested an extreme example to prove it.

Fast forward to some years later and it flared up again on ??? forum, so Dan Wiggins [a SONAR systems designer in real life IIRC] of Adire/Avatar Audio wrote an excellent paper based on TD's work complete with the math, etc., that TD had left out and even it didn't sway some folks, so not being nearly as sharp as these guys I'm only going to post the article and the 'gentle reader' either understands or at least accepts it or not, in which case we'll have to agree to disagree : http://stereointegrity.com/wp-conten...ooferSpeed.pdf

GM

[Old Guy]

Interesting read...so I should correct my argument to read a 3 inch coil with higher inductance might have less HF response than a 4 inch coil with lower inductance?

Or did I miss the point?

[analogadikt]

If we accept the argument put forth in the paper linked to in post #13, inductance of the cross over shall also slow down a woofer's transient response? Running it full range shall improve it, but then cone break up has to be considered?

Regards,

[GM]

Interesting read...so I should correct my argument to read a 3 inch coil with higher inductance might have less HF response than a 4 inch coil with lower inductance?

Or did I miss the point?

Yeah, guess you kind of did in that mass lowers efficiency, inductance rolls off HF if not driven with a matching impedance amp or has impedance compensation [zobel], i.e. the HF BW doesn't change due to inductance, just its roll off slope, so assuming the diaphragm is large enough to push its breakup modes above the VC's limit, the smaller the VC's diameter, the wider the driver's HF BW; or as so many prefer to [erroneously] call this a driver's 'speed', hence can accelerate 'faster' than a larger diameter VC, yet the reality is that it physically accelerates 'slower' in time because it has to cover a wider BW.

While we're on the subject, might as well throw in the [erroneous] 'jump'/'attack' factor, which is when an over-damped system can't reach the limit of the transient's impulse signal before 'letting go' [decay], creating a gap in it relative to the HF driver[s] response[s] that will complete it.

Then there's the 'slow', under-damped woofer system, i.e. won't let go of the transient's impulse signal in proper time, overlapping/comb filtering with the low end of the HF's response.

Of the two, critically to over-damped is generally preferred for HIFI whereas modestly under-damped is the norm in HT, mobile audio, prosound apps as witnessed by the plethora of mild to extreme under-damped vented alignments promoted/used.

Hope all this makes sense as it's somewhat counterintuitive without the real world measured examples Tom used.

GM

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If we accept the argument put forth in the paper linked to in post #13, inductance of the cross over shall also slow down a woofer's transient response? Running it full range shall improve it, but then cone break up has to be considered?

Regards,

Correct, speakers are a system, so any added resistance, capacitance, inductance should be factored in calculating cab alignment, power requirements, etc.. A big deal with high output impedance systems, but p-p, SS not so much and all digital not at all.

GM

[mah]

On woofer speed(easy read):

http://stereointegrity.com/wp-conten...ooferSpeed.pdf

[LICORNE]

I read Danley's document , very interesting.

What about dual voice coils used by JBL .

Would it make it faster ? If it's to fast does the sound get fatiguing?

[GM]

JBL DVC? Not sure what you're referring to, asking.

For me, modestly over-damped/'fast' just sounds 'right', whereas the slight 'ringing' of modestly under-damped/'slow' systems can be quite irritating and highly resonant drives me out of its locale, though assume it's due to having loud tinnitus since ~age 3 thanks to a severe infection/surgery in both ears, throat, so apparently it depends on the individual since the world's most successful speaker manufacturer among many others that historically have marketed highly resonant/'slow' systems.

GM

[Old Guy]

The only DVC stuff from JBL I'm aware of is the car stereo subs. Those IMHO aren't HIFI.

Not claiming I know of everything JBL has made but I've used most of their Pro stuff at one point or another.