Dumb speaker question

[loxley11]

When dealing with passive two- and three-way speakers, is there a crossover within the speaker? Forgive my ignorance, but as far back as I can remember, I've only dealt with active and single-cone speakers, so I seem to have a large hole in my speaker know-how.

 

thanks,

drew

 

p.s. can anyone recommend a good one? I'm thinking 12" + 8" + 4"(or horn). superior configurations are welcome.

 

[ITGITC]

Hi Drew.

 

Yes. In a passive speaker there is a crossover.

 

I like a pair of these LINK for use with my keyboard.

 

Good luck (It's never good when one finds a large hole in their 'know-how'. (Your secret's safe with me, Drew.))

[Byrdman]

Gack! 75lbs! Each! That's getting really dedicated to ones sound.

[MoodyBluesKeys]

Short answer is yes -- passive crossover is the name. Capable of working well, but not high efficiency (a fair amount of power is lost in the inductor and capacitor of the crossover).

 

The trend toward bi-amping and tri-amping comes about because then the crossover is done at very low power BEFORE the amplifiers, meaning that the amplifiers can transfer all their power to the individual speakers in the enclosure rather than a good bit of it being soaked up in the passive crossover.

 

Passive crossovers are cheap compared to more amplifiers in low power operation - but not in high power systems where you could potentially lose thousands of watts of power in the crossovers.

 

Jim

 

[JeffLearman]

12" + 8" + 4" would be an unusual and less than ideal driver combination. The 12" and 8" drivers would have too big a shared range, as would the 8" and 4".

 

A more typical 3-way would be 15", 4", and 1".

 

Another advantage to powered speakers (over what MoodyBlues mentiones) is that when each amp drives only one driver, it can do a much better job of "damping". Essentially, these amps can be fine-tune designed for their intended driver to control the cone's movement to very closely match the input signal (rather than merely controlling the output voltage to match the input voltage, and expecting the cone to react linearly). Most modern amps include damping, but with compromises to handle crossovers and handling multiple cabinets.

 

So, powered speakers have a big leg up on passive speakers for both accuracy and efficiency. Usually these two goals fight against each other in speaker cabinet and driver design, but in this case it's a win for both.

 

I use passive speakers, though, and find them perfectly suitable. I use JBL JRX112M wedges, which are 2-way 12" cabinets with horns -- horns being vastly more efficient than speakers, most of the power goes to the woofer. I'm sure they'd sound anemic next to Tom's speakers, but they're affordable, versatile, and I can carry both in one trip. They will not thump bass to make your chest vibrate like a pair of 15" cabs can, but I rely on the bass player to do that.

 

They also work fine as a pair of disco speakers for a small venue. Add a subwoofer if you want the thumpin bass.

 

In any case, make sure you have plenty of good clean power. My JBL speakers are rated at 250W continuous, 1KW peaks, and they're well matched for my power which is rated at 375 WPC continuous (into 8 ohms), with reasonable headroom.

[MoodyBluesKeys]

Learjeff is quite correct, I just didn't take it that far. As far as the difference in crossovers:

I have a pair of JBL EON 15G2 for main; and a pair of cheaper Gemini 10" powered speakers with 10" woofer and a horn, 100 watts RMS that I have been using for small gigs and stage monitors. I just got the first of two JBL EON 10G2 - it absolutely blows away the Gemini speakers, even though it is about the same size, and even a lower weight.

 

The JBLs are definitely worth the extra money. I use the FOH speakers for bass (since I normally play bass with one keyboard), the 10" are not that potent, but they sound good on other things.

 

The high-end JBL and Mackies with three-way are even better - they are more accurate at the output being same as input except louder.

 

I have found that feeding the JBLs directly from my later keyboards does not sound as good as when I use a small mixing board between - believe this is due to impedance considerations - the keyboards are balanced outputs. Still - just having the little mixer in the JBLs is very convenient for the times I want to carry a minimum amount of gear (and this becomes a larger percentage as I get older).

 

Jim

 

[JeffLearman]

MB, it's not impedance. These are line level devices, which are relatively high impedance (10K-50K ohms). There wouldn't be a significant difference bewteen the two (unless your keyboard's outputs are broken).

 

Balanced vs. unbalanced shouldn't matter either, since these output circuits are designed to drive either kind of input. However, that circuitry may have its tradeoffs.

 

Might be the placebo effect. It's *really* hard to avoid. I remember wondering what a particular button did once, and was convinced I heard clearer highs with the button pushed in. I tried a blind test and found out that I couldn't tell one case from the other, not a bit. I later found out that the button was supposed to have no effect in the particular case.

 

Decades ago, several highly reputed reviewers got egg on their faces when they reported that using a magic marker on the edge of CDs made them sound better. It happens to the best.

[MoodyBluesKeys]

Jeff - I would agree, but I also have an older Kurz K2000VP - I can feed it direct into the JBLs and it sounds exactly like the sound if going through the mixer. The PC2X and PC3X on the other hand have a noticable difference. I did some direct A to B testing by feeding both 1/4" jacks on the 15" JBLs, one with a direct feed from the aux outs on the PC3X, the other going through the board - this way all I had to do was turn down one volume control and up the other on the JBL. I notice a similar effect in my studio, where the PC3X is feeding an eMu 1820M going through the DAW, then the output of the DAW goes out through the 1820M to the JBLs.

 

Even though I've worked with audio for 40+ years in broadcasting and music - I can't really describe the difference in quantitave terms - it does not seem to be distortion, it is definitely some kind of coloration - the sound is "sweeter" and "cleaner" sounding when an intermediate device is in the middle. One thing I haven't tried yet is setting the XLR connector for line and feeding through the XLR instead of the TRS 1/4" connections. The difference seems to affect acoustic piano sounds mostly - I used the PC3X for the last recital in my piano studies instead of the nondescript acoustic spinet that was available. I was actually quite surprised at the difference, and spent some time trying to isolate it. Playing with a group in an ensemble, I don't think it would be noticable; but in solo performance the difference is readily apparant.

 

Jim

 

[loxley11]

Thanks, guys! Pardon me for getting off topic, but I have to rail for a minute here. Actually, I borrow those 10" JBL Eon G2s from my dad all the time, and I've never liked them. People rave about them, but to me it sounds like the highs have been totally eq'd out. I've used them running straight from my keyboard and with a mixer (Yamaha MG12/4) in between. Maybe I'm missing something major here but like Jeff says, both keys and amp have line level inputs/outputs. What's up with that? My vintage tube Fender Vibrolux sounds cleaner to my ears.

 

Jeff and Blueskeys, thanks for all of your advice. Sorry for my digressive ranting.

 

Drew