advertisement


3rd edition of Floyd E. Toole's "Sound Reproduction"

The happy compromise corresponds to where the horizontal dispersion of the horn meets(matches) that of the Bass/mid.
 
There's no such thing as a "bad" crossover frequency, as long as it's well-executed.
 
Nowhere does he say the M2 is the perfect loudspeaker, he says it's "arguably as good as a speaker gets these days", that they represent pretty much where we(Harman)are, that they are "super good" but even so it doesn't guarantee what you play through them will sound great and if 'someone somewhere makes the perfect loudspeaker' that fact wont change.

Fair cop Cooky. I made 5 out of 2 + 2. Apologies.
 
There's no such thing as a "bad" crossover frequency, as long as it's well-executed.

As I understand it even an ideal crossover (where the slopes match perfectly) will have time domain anomalies once the order of the slopes is >1.
Whether or not these time domain imperfections are audible is open to debate. I believe they may be at LF and therefore IMO the lower the XO frequency the higher the possibility is is "bad".
Actually I tried argue that it doesn't matter with some very experienced speaker designers and I lost the argument.
 
Crossovers are a "necessary evil" - if we could have a driver that covered 20Hz-20kHz without distortion or narrowing we'd never voluntarily add a crossover! Since voice, which we are most sensitive to, is predominantly 300-4000Hz I think it's desirable for one driver to cover that range. It's difficult for a driver to perform well over even just a decade, ISTM a slightly smaller range sitting inside the above range is one reasonable approach.
 
Last edited:
Well yes the D2 is a dual annular diaphragm comp but its the nature of that fact(2 lighter separately driven dias) that allows the extra extension in HF. Many prefer the 4" Be comp sound to the D2(but the D2 is 20% the cost) The Array 1400/9800/9900/66000 are all 3 ways though the 66000 has 2 1501al bass drivers, one only cover up to 150hz and its super tweeter kicks in at 20Khz, so is augmented at both ends of the frequency range.
JBL, TAD and Tannoy seem to produce excellent speakers with that circa 800hz xover point-myths and hifi fora rules eh? Incidentally those who've heard my 9800 clones comment on how nice their mid range sounds-female vocals are handled exceptionally well, they have scale, clarity and immediacy/real presentation-something merlin has waxed lyrical about in other threads so I really wouldn't base '2 way with horn loaded HF' opinions on those Chinese knock offs you had-their comp drivers retail for $200 Australian a pop-that's budget PA territory and I'm not surprised you got rid.

Yes, I believe that the M2 design objectives were lower cost and loudness, not performance.

By the way, my opinion is not solely based in those "chinese knock-offs" but also in extensive listening of the 2402 Pioneers of a (then) local audiophile. Even when used with the optional tweeter.
 
Adding to Cooky's post - 800hz isn't anywhere near 'the fundamentals range of most acoustic instruments.'
It is however a great compromise. Other than those listed above, I've heard others, even own another make with a horn crossed in this range: it remains a happy source of musical pleasure and delivers unforced clarity.


300Hz would be at the middle of the fundamentals range for the majority but 800Hz is still at the top of the range for many.
And you mustn't forget that several instuments produce harmonics that are as high in level as the fundamental note:

music.gif



This is a spectrogram from a R.Strauss orchestral work:

DObh4uU.jpg



I think that for acoustic instruments it would be best to have a single driver cover the lower- and core-midrange (~150-250Hz to ~2KHz).
This is for direct radiation or mixed speakers because multi-channel horns driven with band-passed SET amplification have specific requirements.
The midrange in SP9/1s I once had was crossed too high at 600Hz.

Idealy for a large full range direct radiation speaker the size of the M2 I think that one should have different channels for sub-bass, bass, midrange and treble.
And the M2's horn is probably acting more as a waveguide, with the compression driver working as a direct radiator.
Yes the on- and off-axis response curves are impressive but I suspect that they'll strugle with complex music.

P.S.: and no reflex or other low frequency crutches allowed
 
Are you capable to elaborate on that?
I dont need to, the wisdom of your post is there for all to see. but just for you. The M2-JBL's new flagship monitor, fully DSP/active, the culmination of new transducer design(bass and HF), a completely new throatless waveguide, the extensive R&D and you say the design objective wasn't 'performance'.
 

I have tried to explain that.
It's a 2-way speaker with a 38cm woofer in a very large box with bass reflex when it should be at least a ported 3-way.
The shortcomings are inherent to the topology.
 
I have tried to explain that.
It's a 2-way speaker with a 38cm woofer in a very large box with bass reflex when it should be at least a ported 3-way.
The shortcomings are inherent to the topology.

Bass reflex is the same as ported. Isn't it?

Other than that I agree with you, in principle. OTOH the M2 seems to have overcome the problems of beaming inherent in crossing over a large driver with a small one - the measurements are hard to argue with! (Although we don't get to see vertical off-axis performance, so the jury is still out if they really have overcome the problems).
 
I dont need to, the wisdom of your post is there for all to see. but just for you. The M2-JBL's new flagship monitor, the culmination of new transducer design(bass and HF), a completely new waveguide, the extensive R&D and you say the design objective wasn't 'performance'.

Yes, let's believe the marketing bla-bla instead.
Very "insightful" of you, unlike my "stupid".

It would be interesting to compare the M2 with the Revel Salon2.
 
Bass reflex is the same as ported. Isn't it?

I agree, wrong wording. There are several ways to "support" bass but in my opinion they all produce unwanted artifacts and affect transient response in a negative way.

Other than that I agree with you, in principle. OTOH the M2 seems to have overcome the problems of beaming inherent in crossing over a large driver with a small one - the measurements are hard to argue with! (Although we don't get to see vertical off-axis performance, so the jury is still out if they really have overcome the problems).

Toole & Co. are obviously big in the power response thing but wider-band use of a driver produces intermodulation distortion and requires a heavier hand in the crossover to flatten response.
 
EQ for M2. Horn eq goes with the territory but the LF looks pretty light rather than heavy....design/use a driver that's good for its intended pass band and forum lore goes away.
I come from the 'there's more than one way to skin a cat' school of thinking regarding speaker design and you wont catch me slagging 3/4/5 way designs, ATC'100A for example can be superb, Gale 401's are great too. All represent compromises.

25793750698_3ff67d628b_c.jpg


24796900987_f6b823d015_c.jpg
 
Yes, let's believe the marketing bla-bla instead.
Very "insightful" of you, unlike my "stupid".

It would be interesting to compare the M2 with the Revel Salon2.

The Revel Salon2 is an excellent Harman research influenced loudspeaker that (although a very small sample) subjectively came out on top against the M2 in a recent bake off scenario..different power amps may well have produced a different result who knows.

Oh please substantiate your not for performance claim.
 
FR & DI plots incl vertical-pattern control in action, oh and take note of the word 'performance'.

27887274969_6b24160ee1_c.jpg

The right wording for that caption should be:

These detailed frequency response measurements of the M2 illustrate the system's exceptional performance in that one particular parameter.

The difference is substantial.
 
The Revel Salon2 is an excellent Harman research influenced loudspeaker that (although a very small sample) subjectively came out on top against the M2 in a recent bake off scenario..different power amps may well have produced a different result who knows.

Oh please substantiate your not for performance claim.

See previous posts.

Frequency response is but a single objective parameter of the multiple aspects that characterise speaker performance.
 
There's no such thing as a "bad" crossover frequency, as long as it's well-executed.

I disagree.
Even with a steep filter you are mixing the sound from two different transducers. This disrupts the continuity of tone and timbre of instruments producing continuous or legato (as opposed to staccato) sound like a bowed cello or a violin, or human voice.

The audibility of a well executed transition may be questioned but the theoretical advantage of not having two drivers cross at a crucial frequency is in my view undeniable. A single wide-band driver would be the best option if it weren't for the innumerous shortcomings.
 


advertisement


Back
Top