SPEAKER: 3 way vs 2 way

Which speakers should we go for?

  • 2-Way Speaker

    Votes: 3 42.9%
  • 3-Way Speaker

    Votes: 4 57.1%

  • Total voters
    7

THORNSZ

Member
So we're about to purchase a pair of speakers for my church and i am pretty confused about which is better. We're planning on getting a pair of JBL PRX735 15" 3-way speakers or a JBL PRX725 15" 2- speakers together with a pair of JBL PRX718XLF 18" subwoofers. I sort of know the difference between the 3-way and the 2-way but i do not know which is better for the application. We're using these speakers for an outdoor/mid-size hall event. This pretty much gonna be our multi-purpose speakers soon.
 

Morte615

Active Member
If multi purpose, so they will be used for different things on different occasions, I would recommend going with 3-way just for flexibility.
 

JD

Well-Known Member
Ok, the concept of "more ways are better" is due to Inter-modulation Distortion. Simply put, if a low frequency is being reproduced at the same time as a high frequency, the high frequency waveform will be compressed as the cone moves forward and stretched as the cone moves away. (Think listening to an ambulance siren as it passes by.) Also known as the Doppler effect. The fewer frequencies produced by any given speaker, the less inter-modulation occurs. Now, you can't get rid of it unless you have a speaker for every potential frequency which is impossible. What is practical is to reduce frequencies into "zones" like Low, mid, and high. In addition, when you do that, the individual drivers can be designed with greater optimization. (Light weight cones for highs, large cones for lows, etc.) So, rule of thumb is- more ways the better....

Now, here's where the rule gets broken- If in the process of dividing up the frequencies and selecting drivers, if too much compromise is made due to cost, you may end up with undersized components that do not preform well.

In your application, you are using the subs for low end, so a three way system would call for your other speakers to be two-way..... as long as you are connecting them with a high pass filter! In other words, the problematic lows should go the the sub but not to the two way speakers you are using for highs and mids. This can be done by using an active crossover and separate amplifiers (best) or by inserting a capacitor in series with your smaller mid/high speakers. Now you're going to ask what size... I don't have the formula right now, but you could start with a 24mfd 200 volt paper or oil capacitor. (Same as used in a ballast!) Not enough mid-lows getting through? Double it by putting two in parallel. Just remember, due to the amount of current in play, stay away from those "radio shack" type capacitors, and don't cheat and use electrolytics ! (many do!)

Note- with capacitors, using a higher voltage one will not effect the circuit, it just needs to be higher then the expected voltage. So, if you can only find a 380 volt one, that is fine. the "mfd" will set your pass frequency, and has a pretty wide tolerance. The single cap will introduce a 6db per octave roll-off which is pretty mellow.
 
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Lextech

Well-Known Member
What are you putting through the speakers? Music? Voice? Full Praise band? What are you feeding them from? Are you planning on adding outboard speaker management? Be specific and someone will be able to answer better.
 

THORNSZ

Member
@JD
all those technicalities help a lot! according to what you just mentioned, i guess i'll base my purchase on that.

What are you putting through the speakers? Music? Voice? Full Praise band? What are you feeding them from? Are you planning on adding outboard speaker management? Be specific and someone will be able to answer better.

Like what i mentioned earlier, it is a multi-purpose PA. It could be music, full praise band, DJ, etc. Im feeding them directly from a Soundcraft Si Compact 32 mixer. what do you mean by outboard speaker management by the way?
 

JD

Well-Known Member
Like what i mentioned earlier, it is a multi-purpose PA. It could be music, full praise band, DJ, etc. Im feeding them directly from a Soundcraft Si Compact 32 mixer. what do you mean by outboard speaker management by the way?

This question really determines a lot when it comes to selection of equipment. "All of the above" is the hardest. Here are some examples:

Recorded Music: The source is usually well compressed which reduces stress on the equipment. Listeners will most notice good bass and crisp highs.

Vocal PA: If you are trying to project someone's voice, a solid mid-range becomes the most critical. Vocal range predominates from about 500Hz to 2000Hz so the system and speakers must be able to handle focused power in that range.

Live Music: Oh boy! This is the least compressed and often is like riding a wild horse. Keyboards can produce sustained power and almost any frequency and toast out the speakers if they cannot handle it, often your high frequency drivers. Drums are good at bottoming out sub-woofers, and your vocalist will required strong mid range components. An experienced sound tech can ride the horse, but if you don't have the background it is best to invest in a compressor/limiter to protect the equipment.
 

Lextech

Well-Known Member
Okay then, we have determined that we have several objectives here that all need to be covered. Now we should make a list of priorities. Since this is for a church I would think we would want a high degree of intelligibility so everyone can hear the person leading the event. Second we need to be able to be able to keep up with a full praise band, so we need some horse power. How do we achieve both? I would suggest that the 735s seem by their spec sheet to be a little better on the intelligibility department. They won’t be as powerful in the lows as the 725s so I would add the subs to them. This way, since you have the SI console you can route everything to the top boxes with left and right and the using the mono out (or matrix or aux, your choice) route only those channels with low frequency information to the subs. This way you get the oomph in the subs of your kick drum and bass and your vocal mics never see them. This will give you better headroom and should prevent extra low frequency information that you don’t want in your subs out of them. Looking again at the spec sheets, but being very familiar with the JBL systems, it looks like that the 718 would be a good match.


BUT, you really need to hear them for yourself, preferably in the venue you are going to place them in with your praise band. So find your local JBL dealer and get a demo. See if they work for you.


Speaker management includes things like eq’s, limiters and crossovers or such all in one boxes like a DBX Driverack.
 

museav

CBMod
CB Mods
Departed Member
Looking at just two-way versus three-way is missing many of the critical issues as well as the point that it is the overall speaker performance and how it fits the application rather than just the specific components or general format that matter. What output do you need or want from the speakers? What pattern or coverage do you need or want? What frequency response is desired? How does the speaker fit into the overall system and application?

Looking at the specific products mentioned and offering some generic comments...

The PRX725 is a dual woofer model and might be a good choice for a multipurpose speaker by itself, however since you plan to use them with the PRX718XLF subwoofers you probably don't need the additional low frequency or overall output provided by the dual woofers, in fact used with the PRX718XLF you might need mutliple subs per main or find yourself turning down the PRX725 to match the subs. And those dual woofers have an impact in terms of size, weight and cost along with things like not being able to pole mount the speakers. The PRX725 runs the 15" woofers quite high in frequency, crossover is at 2.4kHz, which along with the dual woofer configuration can commonly lead to some interesting variations in the speaker pattern through some of the frequencies critical for intelligibility. Unless your content is very low frequency oriented and you can deal with some of the idiosyncrasies of the dual woofer design then dual woofer mains along with subwoofers are usually not my first choice for a multipurpose system.

The PRX735 would also be a good choice for a standalone system without subwoofers, especially in terms of clarity and intelligibility. Matched with the PRX718XLF subs it would probably be the highest quality combination but at some cost in terms of size, weight, mounting options and cost.

If you plan to always use subwoofers then for a multipurpose system I would actually look at the PRX718XLF subs in conjunction with the PRX715 or PRX712 mains. That gives you a fairly well matched, full range system with smaller, ligher weight mains that can be pole mounted on the subs or by themselves (or even used as monitors). The PRX715 might be the better option here if the mains might at times be used without the subs or if you need every bit of output, otherwise the PRX712 mains with the PRX718XLF subs might provide a nice compact, full range, flexible multipurpose system.


Looking toward the future, if you plan to eventually use the speakers in a specific space then you may want to consider factors such as whether the pattern (a loosely nominal 90x50 for all of the PRX mains) and output of the speakers is appropriate for the space and application. Will the speaker sufficiently cover all the listeners and help keep the audio energy directed at the listeners and away from reflective walls and ceilings? Will the mounting options work in that space and not affect sightlines, etc?
 

OneEng

Member
So we're about to purchase a pair of speakers for my church and i am pretty confused about which is better. We're planning on getting a pair of JBL PRX735 15" 3-way speakers or a JBL PRX725 15" 2- speakers together with a pair of JBL PRX718XLF 18" subwoofers. I sort of know the difference between the 3-way and the 2-way but i do not know which is better for the application. We're using these speakers for an outdoor/mid-size hall event. This pretty much gonna be our multi-purpose speakers soon.

I would highly recommend the 735's for several reasons:

  1. The vocal reproduction through these 3 way's is superior to the 725's to my ears. The 735 is simply more musical when reproducing vocals, strings, and the like.
  2. For much the same reason, stand-alone operation of the 735 is better than the 725's.
  3. The one area where the 725's might have been an advantage is minimized or eliminated by using them with subs (ie the 725's can put out more LF than the 735's)
While it may be true that the 725 can put out more LF than the 735 can, I think you will find that a single 735 will keep pace with a pair of PRX718XLF's .... ie it is more than enough for your applications.

The one application that I would recommend a 725 instead of a 735 would be for hip hop EDM music reproduction.

Most importantly, I think you should go hear these speakers yourself it is at all possible. The answer will be obvious I would think ;)
 

venuetech

Well-Known Member
Departed Member
I did notice that the 735 units are recommended to be stacked or hung not pole mounted so that may limit their flexibility as "multi-purpose speakers"
 

OneEng

Member
I did notice that the 735 units are recommended to be stacked or hung not pole mounted so that may limit their flexibility as "multi-purpose speakers"
Yea, they weigh 77lbs each. I wouldn't want to try to put them up on a pole ... even if they had cups ..... which they don't ;)

Having said that, I usually see them stacked on top of subs. When used stand alone without subs, it is easy enough to get them up on a table.
 

mercerj

Member
Hi, i know this tread is old but im also interested in the PRX 735, i do gigs but sometimes have really big gigs where i wil use subwoofers now my question is, seeing that the 735s is 3 way (low mid and high frequency range), adding a subwoofer and using the crossover on the sub out to the tops, is the frequency range going to change to 4 way..?? sorry Im not to clued up with sound if someone can please help me with this...
 

rwhealey

Well-Known Member
Hi, i know this tread is old but im also interested in the PRX 735, i do gigs but sometimes have really big gigs where i wil use subwoofers now my question is, seeing that the 735s is 3 way (low mid and high frequency range), adding a subwoofer and using the crossover on the sub out to the tops, is the frequency range going to change to 4 way..?? sorry Im not to clued up with sound if someone can please help me with this...

Yes, that will be a four way system (the signal will be divided into four frequency bands). Why does it matter?
 

JD

Well-Known Member
using the crossover on the sub out to the tops, is the frequency range going to change to 4 way..??
If you are >removing< those frequencies from the current 3 way system, it would be 4 way. If the subs are being fed the same signal that goes to your 3 way system, but are doing their own low-pass thing, then you are running a 3 way system with supplemental help from the subs on the lows. Remember, the key advantage of a multi-way system is that it removes intermodulation distortion by limiting cone movement on drivers that are trying to produce higher frequencies. (Doppler effect) If the bottom of your 3 way is also receiving the very low frequencies, then you have missed an opportunity to limit intermod on your mid-bass, reducing the advantage.
 

mercerj

Member
Ahhh I see so in the end the would sound even better being a 4 way then.!! Now I have another Quesion, is it at all possible of making it a 4 way with non powered bassbins and powered tops..? Sorry but I'm still trying to learn all these things so thank you all for your help...
 

mercerj

Member
Hi JD, just wanted to thank you for your help yesterday. There is one more thing i would love gor you to help me with seeing that you really know allot redarding sound... I havent bought the prx735s as yet, now as i have read the read and you have explained to me it is way better going more ways ragarding frequencies and buying the prx735 is a good choice, but im looking for as much oemf as possible with the best sound quality as i can get with the amount that i have. As im going to sing through the sound i want it to sound perfect but going powered what would you say is the best i can buy for about $2500.. I have have a samson sxd7000 amp and EVP-X18B subwoovers.. I dont use them with every gig so im looking for powered speakers if you can please show me in the right direction.. I do love the jbl prx700 series bit what would you prever,,?? thanks in advance
 

JD

Well-Known Member
I would always say rent before you buy. What works for one person may not work for another! Multi-way systems can either be passive, active, or a mix of both. Generally, a passive system is laid out "Signal > Amplifier > Crossover > Speakers", and an active system is laid out "Signal > Crossover > Amplifiers > Speakers." The thing that makes it 2 way, 3 way, or 4 way is when the frequencies are broken into bands. Actual frequencies used depend on equipment and the soundperson's own secret recipe ;) Here's an example: Sub bass: below 100Hz, mid bass 100 to 350hz, midrange 350 to 1200hz, highs: above 1200hz. NOTE: That is only one person's recipe and every sound person has their own! So, there are a few rules- High frequency drivers blow up when you feed them low frequencies so you have to be aware of the manufacturer's recommendations. Bottom end should also have a practical roll off that should be at least as high as the cutoff frequency of your subs. Vocal fundamentals are between 400 and 800 hz, so it's not good to do a crossover in that range. Also, as you can see, your midrange drivers are the most important for clear vocals. Intermodulation distortion is most common when you are feeding something like electric bass or keyboards into the mix. One final note: More ways is not always merrier! Having less drivers but of better quality is a better choice as long as you are free from intermodulation. Good luck!
 

mercerj

Member
Hey JD thank you for coming back to me and sorry for the delay in reply. Ok so I went and bought the Prx735s and 718 subwoofers but it's as if the bassbins doesn't keep up, those speakers really are loud.
Ok so another Question, what else is there that I can use to make my sound, sound best, I was looking at the DBX venu360 but I don't have any experience in drive racks what so ever, what does a drive rack do exactly? What I'm looking for is something that will keep my voice and my backing track and guitar at the same level with every song at a desired dbl level so that I don't have to stretch to the desk the whole time to get the level right between my voice backtrack and guitar... Is there something like that and can the Dbx venu360 do that..?? My desk that I use is a Behringer Xenyk Qx1222usb.
Thanks for the help so far..
 

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