passive v. active monitors

hey guys,

i realize this topic has been covered in previous threads which i've read through but i'm still unclear about a few things (well a lot of things but i'm gonna ask about two):

1) when researching about the advantages/disadvantages of passive and active monitors i keep seeing people say that one reason active monitors are better is because the amps are "matched" to the speaker. that's great, but what the heck does that mean exactly? (if anything)

2) people keep talking about the need to power passive monitors with "good" amps. other than providing the appropriate power consistently, what makes an amplifier good? what are the differences between a pro level and consumer level amp? i'm sure i'm missing something hear but it seems like the amplifier has a pretty simple job to do.

thanks in advance...

OK

You've got a Ferrari GTO and you fit it with 'General Grabber' All Terrain Offroad Mud Tyres!

The Ferrari's a great car - the Grabber AT is a great tyre on your 4 X 4 Jeep up in the hills but the two just don't go together

No, what you need to do if you are Mr Ferrari is find a tyre company who can design and produce a tyre suited to to the GTO that will hang on tight to the tarmac when cornering at 130mph

Active monitors have amplifiers custom tailored to suit the characteristics of the drivers (speakers usually a 'woofer' for the low frequency and a 'tweeter' for the high stuff + maybe a mid-range unit or two in some designs) used in each individual moitor

There are many advantages in active designs, here are just a few:

The components of each monitor are all designed to work perfectly with each other

The amp is connected to the driver with ulta short cables minimising loss

Most active designs have one amp per driver unit which is custom designed to match them

More compact - no speaker cables - no space required for the amplifier in the rack

Self contained

Overall 'active' work out cheaper than buying seperate monitors and amplifiers of comparable quality

I have two sets of active (Genelec 1032A and Fostex 6301B) and one set of passives - the ubiquitous Yamaha NS10 (Industry Standard) powered by a Rauch 25s power amp

For me I would choose active every time - they win hands down

Cheers
ping

"Matching" really means employing an active crossover filter tailored to the characteristics of the speakers.

Next to the drivers themselves, crossovers are the weakest link in any speaker system, so letting the vendor design that piece for you pretty much eliminates that concern. Active monitors are going to have active crossover filters in front of the power stage, as opposed to passive filters in most unpowered, non-bi-amped monitors.

Going passive means either using passive crossovers or having two stereo amplifiers plus an active crossover. No real cost savings there unless you already happen to have those things. Otherwise, active monitors are definitely the way to go.

i was considering passives as i will probably be buying an amp/receiver soon to drive the surround sound system i want to put together for my home theater system (tv's in the same room as where i mix).

I wouldn't use a home theater amp to drive monitors. Mine, and many other passive monitors are 4 or 6 ohm impedance, enough to choke most home theater equipment. You'd need a dedicated power amp without fancy pre-amp sections, tone controls, DSP, or anything in the way between your source and the speaker. Think straight wire with gain for a good set of passives.

do you think manufacturers really spend the effort to match the amp to the active speaker in low to mid level monitors?

Absolutely! And with actives, it's much cheaper for them to incorporate that into the design.

obviously i would base my decision on hearing the monitors.

Good plan!

is there anything specific you can listen for when auditioning monitors for poorly matched amps? would a poor crossover cause the speaker to hype certain frequencies and hide others?

Nothing specific. And crossover design is critical to every speaker. Typically tweeters take over about 2kHz, right in the middle of the critical midrange area. A mismatch here can do all kinds of wierdness, like overlapping too much and causing a peak... overlapping too little and causing a dip... mixing crossover slopes and causing some strange phase interactions (kinda like comb filtering)... lots of stuff to consider.

I'd say in your situation it sounds like actives are the way to go.

Beware, however, that some amps might color the sound - especially when you're looking at using a home theater amp. you need an amp that is just pure, clean amplification and not one that will boost the lows or mids to appease the home theater crowd.

+1 to that, I will be shopping for a pair pretty soon, and it will be the ones that have the nicest (flat) curve on a graph - the rest is up to my eyes and my wallet.

The BOSE effect... a little smiley face curve in the frequency response makes people think it sounds bright, powerful, generally more pleasing than a 'flat' comparison. Reduce the 100Hz range a bit, pump up 50Hz and put a slow rise above 10kHz and you'll make some sales. ...Not what you're looking for in studio monitors.

In a home theater amp there's a whole lot of signal processing you don't need for monitors. All the surround processing, bass management, EQ, compression, and what not will be a problem. Sometimes there's a "direct stereo" or "bypass" mode the will alleviate that, but I'd rather spend $300 on a modest plain Jane power amp than a comparably priced but fluffed out home theater receiver. You don't need thousands of dollars for a Bryston to get a good monitor amp (though they're sweet and I wish I had one) but a good brand amp is a must.

Sound reinforcement amps are OK, and are near impossible to kill in a studio. But they'll come with a noisy cooling fan. There are some fanless studio amps that are reasonably priced out there if you shop around.

Also, what I had mentioned about impedance is important, as well as some other compromises that come with sticking 5-7 channels of power amp in a single chassis. Home speakers are generally all 8 ohm, while monitors can be 4. Half the impedance = twice the current draw, which will overheat and kill an amp not rated to take that kind of abuse. Onkyo is one of the few brands that rate their amps at 4 ohms, but most of your generic Sony, Pioneer, Kenwood etc. won't handle anything less than 8 ohms. They'll also use integrated chips for most if not all the amp circuitry, which are cheap and functional, but may have higher distortion, poor damping factor, and other specifications that will be inferior to a dedicated stand alone power amp.