New JBL PRX 600 series

[Randyman]

agedhorse wrote:

If you need a cabinet that will do monitor duty, the 615M cabinet will do this but the 635 won't.

 

 

Good point. And there's certainly no substitute for hearing these specific speakers in action. But I'm sure there's pluses and minuses for 2 way vs 3 way, and the prx 635 price and weight are making me motivated to better understand why i'd want one over the other. it's too bad this is at the end of a long thread, I'd love to hear from folks that have experience on this subject (though it does seem that most s.r. speakers, even the pro stuff, is mostly 2 way).

 

Looking at the JBL website, some interesting things of note:

Prx 615m goes down to 45hz (+3db)and the

Prx 635 only goes down to 53hz (flat) and 50hz (boost)!

 

Which leads me to conclude that the advantage of the prx 3-way system is in its enhanced definition/smoothness of the mid-range, and not more low end like I was hoping.

 

 

Within the same line, on the 3 way, the midrange vertical dispersion will probably be quite a bit wider which may be a distinct disadvantage, but the midrange may be a little more natural

 

 

But still, that could be significant- in my experience it's the mid-range that is the sticking point in most s.r.: I'm the first to cry foul with too much harshness in the 1-3k zone. How to achieve back-of-the-room dispersion without overall harshness, which I imagine 3 way designs are supposed to help with over 2 ways.

 

So, apart from my presuppositions- if the wider vertical dispersion from a 3 way could be a distinct disadvantage, then in what circumstances would 3 ways be preferable over 2 ways? I'm assuming noone would buy it if there wasn't a noticeable improvement in sound. Interestingly, all of these prx speakers are rated as having 90x50 coverage pattern.

 

Thanks,

Randelph

[agedhorse]

The 3 way is more of a shorter throw box as the wider dispersion and lower sensitivity of the midrange cone driver compared with a more professional level compression driver that would be found in a (more professional) 2 way box would lead to less midrange as you move farther away from the source.

 

A good 2 way box will have a crossover point of say 800-1000Hz, at this point the directivity will be much lower in a cone driver than a compression driver on a suitable horn flair. A midrange cone driver will be roughly 120-140 degrees vertical (spherical actually but vertical is generally the bigger sticking point) whereas a suitable horn flair on a horn will be closer to 60 degrees (on a 40 deg vertical) and the dispersion angle will decrease as frequency increase up to the CD point of the horn. This is where the added sensitivity (plus that of the raw compression driver coupled to the horn which is an acoustic transformer) comes from.

 

One benefit of a 3 way box is that a smaller format HF driver can be used, which may sound better as it's crossed over higher and the geometry of the phase plug and horn do not have to worry about at least one full octave at the bottom (most difficult if HF response must be maintained) of the range.

 

Then there's the added complexity of a 3 way crossover and the additional phase shifts and acoustic summing that must occur.

 

It's not a simple answer because it's a complex question.

[hemismith]

 

They also compared the QSC K12 and the PRX 612...he like the K12's better.

 

 

This isn't encouraging -- the K12 reviews weren't usually that great, and the 612 was supposed to be better than the 512.

[agedhorse]

 

This isn't encouraging -- the K12 reviews weren't usually that great, and the 612 was supposed to be better than the 512.

 

 

Just one opinion...

[hemismith]

True!

[Randyman]

Aged horse wrote:

Then there's the added complexity of a 3 way crossover and the additional phase shifts and acoustic summing that must occur. It's not a simple answer because it's a complex question.

 

 

So, if there's no broad generalities about the desirability of 3 ways over 2-ways, then it comes down having experience with specific 3-ways that made the added expense and weight of the 3-way worth the trouble.

 

Are there any examples that come to mind of mid-grade 3-way speakers that have a noticeable advantage over comparably priced 2-ways? In particular for midrange smoothness/clarity or low end extension?

[agedhorse]

 

Aged horse wrote: So, if there's no broad generalities about the desirability of 3 ways over 2-ways, then it comes down having experience with specific 3-ways that made the added expense and weight of the 3-way worth the trouble. Are there any examples that come to mind of mid-grade 3-way speakers that have a noticeable advantage over comparably priced 2-ways? In particular for midrange smoothness/clarity or low end extension?

 

 

If size, weight, directionality and throw/mid band sensitivity are not important, the PRX535 and HPR 153 are pretty good at that price point. I think the SRX-715 might be a better choice for a 2 way though...

[pgtcobra]

anyone try prx615?

[agedhorse]

 

anyone try prx615?

 

 

For powered, 2 way it's certainly a contender.

[qtuner]

Has anyone found out if the noise gate is in this speaker?

[lifeloverwg]

agedhorse wrote: Good point. And there's certainly no substitute for hearing these specific speakers in action. But I'm sure there's pluses and minuses for 2 way vs 3 way, and the prx 635 price and weight are making me motivated to better understand why i'd want one over the other. it's too bad this is at the end of a long thread, I'd love to hear from folks that have experience on this subject (though it does seem that most s.r. speakers, even the pro stuff, is mostly 2 way). Looking at the JBL website, some interesting things of note: Prx 615m goes down to 45hz ( + 3db)and the Prx 635 only goes down to 53hz (flat) and 50hz (boost)! Which leads me to conclude that the advantage of the prx 3-way system is in its enhanced definition/smoothness of the mid-range, and not more low end like I was hoping. But still, that could be significant- in my experience it's the mid-range that is the sticking point in most s.r.: I'm the first to cry foul with too much harshness in the 1-3k zone. How to achieve back-of-the-room dispersion without overall harshness, which I imagine 3 way designs are supposed to help with over 2 ways. So, apart from my presuppositions- if the wider vertical dispersion from a 3 way could be a distinct disadvantage, then in what circumstances would 3 ways be preferable over 2 ways? I'm assuming noone would buy it if there wasn't a noticeable improvement in sound. Interestingly, all of these prx speakers are rated as having 90x50 coverage pattern. Thanks, Randelph

 

Not sure where you're reading the PRX 615 goes down to 45hz -3dB, the spec sheet I'm looking at claims 54hz with 45hz being the -10dB.

 

Aged Horse already pointed out the challenges with three way speakers, I would just reiterate that the only way to tell what you think is to listen to them side by side. Sound is a pretty subjective opinion and you're the one that has to live with the decision.

 

As an aside, I just heard from a local dealer that he still prefers the sound of the QSC series, but opinions are like a$$h@les........

 

Listen for your self! Winston

[Randyman]

Winston,

Yes, there's no substitute for listening for yourself. BUT WHAT IS THE REASON FOR MAKING THESE 3 WAY BOXES? Someone must be buying them, and I'm sure there are folks with 3 way box experience that have good things and bad things to say about their place in s.r.(once again, compared to similiarly priced 2 way speakers- we're talking $800-$1,300 speakers). I understand, as Aged Horse said, it's a complex subject to talk about in general. So let's talk about specific models and how well they worked.

 

Personally, I don't see a test in a store as being very definitive. I discovered that with keyboards, it wasn't till I got it home for a test drive and taking it to gigs that I could really tell what i was dealing with. In the same way I believe it'd be very helpful to hear from folks that have in-the-field experience with 3 ways. I'm guessing that this being at the end of a long thread not much attention is being paid, or that there isn't a lot of folks with 3 way s.r. speaker experience, or mums the word!

 

Randyman

[agedhorse]

l have plenty of 3 way experience hence my comments. I have also designed several commercial 3 way products, again by comments are based on that experience too.

[modulusman]

If I was looking for new speakers I would definately be interested in the 635s. The box is small and light for a 3-way so it shouldn't be real unsteady on a stand.

[lifeloverwg]

I have experience with the three ways we run which are Community 3294's. When we were looking to upgrade from our JBL Eon's I put together a list of speakers that fit our price range and weight restriction. Most three way speakers didn't fit under out weight limit though and others were just too expensive for our needs.

 

In the end I set up a listening session in our back yard with three options and our group chose the Community for what we perceived as better mid range clarity and depth. It also had slightly better pattern control than the PRX 512 we were comparing it against due to its bigger horn. Ours work very well for us and our needs, but there are plenty of two way boxes that work just as well too. I guess they make three ways because people like me buy them....

 

Plenty of people use three way speakers, but for all the reasons Aged Horse pointed out, they tend to be more popular in the pro market where they can be bigger and more expensive. The other area you tend to see them a lot is in the lower end market where buyers want there rig to look big and assume that bigger must be better.

 

Winston

[agedhorse]

For some playback type applications in shorter, wider rooms, 3 way can have an advantage due to their wider, less beamier dispersion (in general, not including the horn loaded mids of course).

 

Don't forget the Vertec and other line arrays are commonly 3 way and with cone driven mids too, but the length of the line improves pattern control and with multiple drivers (larger Vertecs use 4 mids each) there's plenty to go around.

[Bobby1Note]

 

Winston, I believe it'd be very helpful to hear from folks that have in-the-field experience with 3 ways. Randyman

 

 

Do some research on these; there are plenty of very satisfied owners at ProSoundWeb, and a few here at HC.

 

http://www.yorkville.com/products.asp?type=29&cat=38&id=254

[Randyman]

Bobby1Note wrote:

 

Do some research on these; there are plenty of very satisfied owners at ProSoundWeb, and a few here at HC. http://www.yorkville.com/products.as...&cat=38&id=254

 

Thanks for the tip on the Yorkville U15- this seems to be a good example of why someone would put up with the extra weight and cost over a 2 way. Cool to see Danley design in a mid range priced speaker. The cost (I saw an active version for around $1400) seems reasonable, but the active version weighs in around 90 pounds (ouch), which is why the prx 635 @ 60 pounds looks exceptional. Sounds like the 60 degree horizontal coverage is problematic in some rooms, requiring 2 per side for wider rooms.

 

I assume the 635 will be similar to the 535. Anyone with experience with the prx 535?

 

lifeloverwg wrote:

 

In the end I set up a listening session in our back yard with three options and our group chose the Community for what we perceived as better mid range clarity and depth. It also had slightly better pattern control than the PRX 512 we were comparing it against due to its bigger horn. Ours work very well for us and our needs, but there are plenty of two way boxes that work just as well too. I guess they make three ways because people like me buy them....

 

 

Yeah, better mid range clarity and depth!

 

 

 

 

Aged Horse wrote:

 

The 3 way is more of a shorter throw box as the wider dispersion and lower sensitivity of the midrange cone driver compared with a more professional level compression driver that would be found in a (more professional) 2 way box would lead to less midrange as you move farther away from the source. A good 2 way box will have a crossover point of say 800-1000Hz, at this point the directivity will be much lower in a cone driver than a compression driver on a suitable horn flair. A midrange cone driver will be roughly 120-140 degrees vertical (spherical actually but vertical is generally the bigger sticking point) whereas a suitable horn flair on a horn will be closer to 60 degrees (on a 40 deg vertical) and the dispersion angle will decrease as frequency increase up to the CD point of the horn. This is where the added sensitivity (plus that of the raw compression driver coupled to the horn which is an acoustic transformer) comes from. One benefit of a 3 way box is that a smaller format HF driver can be used, which may sound better as it's crossed over higher and the geometry of the phase plug and horn do not have to worry about at least one full octave at the bottom (most difficult if HF response must be maintained) of the range. Then there's the added complexity of a 3 way crossover and the additional phase shifts and acoustic summing that must occur. It's not a simple answer because it's a complex question.

 

 

Can't say I understand most of what you wrote there.

[Hegmatronicon]

The main problem i have with these speakers is the pricing in Australia.

A lot of places dont have the 600 series yet - but even the PRX512 speakers are around $1400AUD EACH! That's more expensive than buying two from the USA, shipped to me.

Only issue then is warranty.

Come on JBL. Help a southern brother out!

[agedhorse]

It's not JBL, look at your government's import and taxation policies. Protectionism at it's best my friend...

[Hegmatronicon]

 

It's not JBL, look at your government's import and taxation policies. Protectionism at it's best my friend...

 

 

Thats a factor - but we're not THAT bad.

[agedhorse]

 

Thats a factor - but we're not THAT bad.

 

 

Yeah, pretty much you are...

 

There's the taxes improters pay and then the taxes that the distribution and retailers pay which also factor into the selling price of equipment from abroad.

[qtuner]

I just received a pair of prx612m's and i will reporting on them soon. I used to have a pair prx512m's that I have returned after I couldn't handle the noise gate anymore. First impressions is that they look much better cosmetically ie. no more orange badge, a little heavier, and the handles suck. I've been to busy to fire them up yet, I'll report back soon

[hemismith]

 

I just received a pair of prx612m's and i will reporting on them soon. I used to have a pair prx512m's that I have returned after I couldn't handle the noise gate anymore. First impressions is that they look much better cosmetically ie. no more orange badge, a little heavier, and the handles suck. I've been to busy to fire them up yet, I'll report back soon

 

 

Great, we look forward to hearing about them!

[marlo74]

Nice subject,

I ordered 2 of the PRX635. I will receive them in 2 days. I plan on posting my reviews after I hear them live. I currently own 2 of the Unity U215Bs. I am very happy with their sound. they are not as loud as the SRX725s but defensively provide nice and clear mid ranges. They do however seem to be more sensitive to feedback than the SRX725s.