Are the very large PHL midranges recommended?

[tech.knockout]

PHL sells a wide variety of surprisingly large bass-midranges(or what they called extended midrange) 8"-12" that defy the norms.

Arent large woofers not meant to handle midrange frequencies because of beaming and cone breakup?

Who has expereince with the following: 3430/3020/3840/2410/2420/2440/2460

sound quality? ease of crossover?


Alot of designs also seem to utterly defy the thresholds of the following link by a large margin:

Best woofer-mid xo point


E.g. the limit for the Seas Thor design is 1.8Khz, yet the crossover freq is way off, 2.5Khz.

I doubt the different materials used in mid-bass should vary their upper limits by that much.

[JohnR]

Correct me if I'm wrong, but by those numbers, a 1" tweeter shouldn't be used above... uh, around 11 kHz?

[jeff mai]

The break-up modes are practically part of the design. In the 3451 these modes begin at 2kHz. Some people don't seem to mind. I could hear tham and I quickly decided they'd be a bear to deal with because it was too near where I wanted the crossover.

Of course they beam, but so does every 2-way with a 20cm woofer crossed at 3kHz. Plenty of these about, including in my own system.

[tech.knockout]

The break-up modes are practically part of the design.

WHat do you mean, if there is breakup at 2Khz, how come theyre being advertised as usable to 4Khz?

Of course they beam, but so does every 2-way with a 20cm woofer crossed at 3kHz. Plenty of these about, including in my own system.

Wouldnt most bookshelf speakers with a 7"/6.5" midbass beam as well? The upper limits of the woofers are 1500-2000, yet most of these 2 way designs are crossed at 2Khz - 3Khz.

Do you know where the breakup starts on a 8" PHL?

[jeff mai]

Originally posted by tech.knockout
WHat do you mean, if there is breakup at 2Khz, how come theyre being advertised as usable to 4Khz?

This is why I said the breakup is practically part of the design. It's part and parcel with the efficiency of the driver. It's unavoidable with stiff cones and strong motors. Many people don't seem to take notice.

Wouldnt most bookshelf speakers with a 7"/6.5" midbass beam as well?

Yes, they do. It isn't as bad as you think, though it does cause a dip in power response.

Do you know where the breakup starts on a 8" PHL?

No. I suspect it would be slightly higher up.

[tiroth]

If you see the characteristic breakup ripples in the FR, something is happening. I use the PR170M0 and there is definitely something going on above 3kHz or so, but this driver is eminently usable to 6Khz.

I remember someone stated that this wasn't truly breakup; I think the rationale was that since this was controlled, damped, and desired decoupling it wasn't "breakup". Personally, I think a rose by any other name would smell as sweet, but the fact remains that drivers CAN sound good despite this behavior, provided they are well designed.

[DSP_Geek]

Originally posted by tiroth
If you see the characteristic breakup ripples in the FR, something is happening. I use the PR170M0 and there is definitely something going on above 3kHz or so, but this driver is eminently usable to 6Khz.

Hmm. Some drivers show breakup behaviour in the *impedance* curves, which is a big red flag as far as I'm concerned.

[tiroth]

This is what I mean. It shows up in the waterfall as well.

Wouldn't an impedence issue mean that the entire cone structure experienced or was affected by an underdamped breakup mode? That would be a little different from the more subtle effect of the outer "rings" of the cone decoupling slightly from the inner rings.

I.e. the voice coil doesn't "know" what is happening unless it's travel is affected, so only certain things will be apparant in the impedence curve.

Logically, some kind of decoupling must be occurring, otherwise there would be a rising response, ne? This seems to be the entire theory behind the Manger drivers, and if you look at their demo holographic images it appears to work too.

[tech.knockout]

the bad thing is that PHL doesnt publish any curves/graphs for their drivers.

This is why I said the breakup is practically part of the design. It's part and parcel with the efficiency of the driver. It's unavoidable with stiff cones and strong motors. Many people don't seem to take notice.

And you found it unbearable? Or your point was that designing a crossover for them is too hard?

Yes, they do. It isn't as bad as you think, though it does cause a dip in power response.

wouldnt there be a massive dip in the off-axis response? Hence narrow sweet spot.

[jeff mai]

Originally posted by tiroth
I remember someone stated that this wasn't truly breakup; I think the rationale was that since this was controlled, damped, and desired decoupling it wasn't "breakup".

I wouldn't call what I measured from the PHL 3451 controlled above 2kHz. It looks like a lumpy lift if you apply smoothing to the FR graph. If you don't it looks like what it is - lots of big spikes. This doesn't mean it couldn't sound fantastic, but given the nature of this sort of thing some recordings would sound much less fantastic than others.

Again - it's what you get if you seek this kind of efficiency from a cone midrange.

The other thing that "gets" you about these big midranges is having this wonderfully efficient driver only to throw 4-6db away below some frequency because of baffle diffraction.

In the end, I decided the 10" PHLs were too big for my room and sold them. Otherwise I would have worked with them.