I Was Considering Active, Then I Watched This ...


high-amp

Showing 12 responses by lonemountain

Some ask for direct comparison of active vs passive of the same speaker and I have done this many times.  SCM 40 passive vs SCM 40A active, plus SCM 50 passive vs SCM50 Active.   In both cases using ATC P1 or P2 amps to drive the passive.  So this yields the same exact speaker, same exact model, same exact amp design and same exact output devices in the passive amp vs active amp set up.  Pretty much a direct comparison except the cable being a factor, I used Cardas 6 foot clear light speaker cable and Cardas clear light 6 foot XLR line cable in both.  

I have done this at shows and at home as well as the shop.  I'm the US ATC importer so obviously I have to do this to be informed and accurate in answering people's questions.  I was also the one who provided the passive and active ATC 50s to Neil Gader for his review in Absolute Sound.   

The simplest way to state the comparison is the tone and timbre (frequency response) are the same between active and passive, the difference comes in image and resolution.   The actives image much better and more finely resolve things like reverb tails, harmonic structures of complex instruments like piano and "room sound" - elements of a recording that reside in the background of most recordings.  You can hear placement of instruments more clearly and hear the ultra fine details of the microphone/gear used in the recording process.  For example, in Stevie Ray Vaughns live recording of Tin Pan Alley, you can tell the microphone Stevie uses for his vocals is a dynamic mic, as the bandwidth of the instruments is much wider in bandwidth than his vocal mic.   

Most of the negatives I read in this thread are from people not really understanding the simple difference.  In its most simplistic difference is there is nothing to be improved or gained with a large quantity of copper (wire) and inductors/capacitors (passive crossovers) placed in line between the amp and the driver.  That's it, in a nutshell.  The endless arguments over cable should be evidence of the sonic influence of cable/copper/silver/wire/etc.  This "passive" solution may be the best idea if you like to play around with different sonics, changing amps, cable and all the rest and it IS fun.  But removing all this copper and inductors/capacitors and wire DOES have direct performance benefits.  

The most significant advantage IMHO is the ability to create linear phase of a speaker, by controlling the individual phase of the drivers.  The second advantage is precise level calibration of individual drivers which can vary by 1/4 to 1/2 dB or more from unit to unit (even more variance in machine produced drivers). Passive crossovers do not offer this kind of adjustment.  The third advantage is avoiding the change in sound of drivers/loudspeakers as they heat up (power compression for example).  The values of the combo of driver/passive crossovers begin to change with temperature changes (increases) therefore changing the sound of the overall speaker.    This is most audible after long periods at higher level, such as experienced in a recording studio where a mix session can last 10-12 hours at 85-90dB SPL (or more).  [note: listening at low level for an hour may not reveal this temperature issue so this may not affect every passive speaker the same.  Some drivers have better cooling or venting than others so there is variance in this side affect among loudspeakers based on driver design and length of listening sessions]

With a properly designed active the differences in the front end are far more dramatic than ever before, yielding just as much fun in experimenting with cartridges, tonearms, DACs, etc. So from my experience, active enables even greater insight into the minute details of recordings and all the associated gear. 


Brad
Lone Mountain Audio
TransAudio Group 
ATC USA Pro and Consumer        
djones51: An active speaker can be an all analog design or a digital input/DSP design and Class D amplifiers, but inputs and amps do NOT make it "active".  The critical issue is simply where the processing takes place, at speaker level [passive] or line level [active]. 

A "powered" speaker is not active and this term does not infer active; active speakers are not "powered".   "Powered" is a passive speaker with an amp [usually] inside, placed before the passive crossover just like any other passive speaker.  A "powered speaker", with processing at speaker level, can be Class D or Class A/B amps or digital inputs or analog inputs.  This powered description is used most often improperly, often by users or dealers (or manufacturers) who don't understand the term either or are attempting to deliberately fool a buyer into thinking that powered and active are the same.   They are a completely different designs and concepts.    

If one focuses on "where the processing is", before [active] or after [passive]  the amplifiers, the "active" label become much easier to discern.     

Brad   
DJones51, its difficult to judge your posts when you say "front end components are not really much of a concern on a properly designed active".  Increase resolution at the speaker (via active technology) and resolution of the front end won't matter?  
Brad


That is not true in my experience. 

I don't think whether its DSP or Analog would affect the outcome either, unless its a low quality (DAC or analog) design masking information.  I guess its certainly possible to hear no difference. 

My preference is not to have a DAC in my speaker, as these designs change constantly. No matter the DAC loaded speaker, the entire package will be obsolete in a year as a new DAC arrives to market that replaces the previous one.  Id prefer to use my own DAC and change that as I see fit.  So analog inputs work for me in light of a sea of constant DAC upgrades.   

Many pro customers have commented to me over the years that not all "active" speakers are very revealing of details.  One can see significant engineering investment into the designers concept of what the "problem to solve" is.  This is of course is fair enough, room acoustics are indeed a huge issue.  High end DSP electronics mated to lower cost OEM drivers may be great at room correction and low on resolution.  While the speaker sounds good in the room it may be poor at revealing the subtle information that many seek.  To my customers way of thinking, this is not good enough.  They want an all out effort in both electronics AND drivers. They will deal with the room as a separate acoustical problem but please please PLEASE make the most revealing speaker possible.

Brad  .        

I think you said it all there KingHarold: you put forth a LOT of effort to correct for issues you encountered.  A true engineering project!  Problems are inherent in every loudspeaker design and I think ATC and Genelec would 100% support you in your effort.  What you accomplished could not have been done in a passive system.  

I think many that dislike active out of hand are just focused on a single feature which is actually not part of what makes a speaker active or passive.  Don't dismiss active because of the amp swap issue alone when there are so many other problems active addresses that cannot be addressed in passive.   Phase Linearity is a big one.  
Brad  

 


It’s a compromise to have active speakers and is technology mostly embraced by the professional audio sound people. They listen for frequencies, not tonal shadings or micro dynamics...certainly not for the differences in instrument voicing or spatial imaging.

I cannot find who posted this, but this is a complete inaccuracy. Pros listen for frequencies? I’ve worked in pro my entire life and I have yet to meet someone who "listens for frequencies". The tonal shadings and micro dynamics is exactly what pros listen to. Instrument voicing and spatial imaging is exactly what a real engineer in a real studio listens to for hours and hours, days upon days. It is not exaggeration to say that someone like Al Schmitt can listen to one track a thousand times before he’s tweaked everything to his and the artists satisfaction. The exact harmonic presentation of the piano with this mic or that one? The position of the mic and how it changes the way the piano sounds. Fixing the small error in a vibration of a snare when one particular tom tom was struck. Building an image out of separately tracked instruments. Using a specific type of compressor on the orchestra that gives it a sexier presentation than a simple full band compressor. This absolutely blows my mind that someone would think pros [specifically recording engineers] don’t understand the details or are ignorant of the very details that audiophiles value. They are obsessed with it!

A comment I read in this thread that recording engineers gave us loudness wars- complete BS. RADIO gave us loudness wars, and Record companies responded as records had to compete to be popular on the radio. Fletcher Munson curves say the loudest song wins and Record companies who controlled everything told their Mastering Engineer to make it louder. The mastering guy absolutely hates this as much as you do! Fortunately record companies do not have the level of control they used to and now artists are creating, funding, recording their own record.
Brad
I decided today that if AXPONA happens this next fall as planned (Chicago), I’ll take a pair of ATC 50 SE’s and pair of 50 passives to compare in my exhibit room. All of you can come hear it yourself.

Brad


Yes, but we did not do an active vs passive comparison.  I did that only at AXPONA.  Reading this thread makes me want to say it's all I will ever do.  I cannot believe there is this much misinformation about active.   

Brad  

@erik_squires

You make perhaps the single most powerful point in the active vs passive argument: does anyone care? For many, flying blind, going by other peoples opinions and the power of brand marketing is too powerful a set of conditions to overcome. If you haven’t stood in a studio and heard what’s on the other side of the glass and then how that sounds in the control room (through a given set of monitors) how would you know? If you don’t understand the science behind active, how would you know? If you are used to an odd sound and that becomes your reference [confirmation bias] how would you know?

While active makes all the sense in the world from a science point of view, I guess it’s like people who buy terrible cars: you cannot talk them out of it no matter what you do! A lot of people bought Cadillac Cimarrons, Chevy Vegas and Ford Pintos! And if you ask someone why, they will defend it with gusto!

Brad

There are many sceanrios where a listener could not tell there were changes to a system.  Of course that does not mean there isnt a difference or it isnt a desireable difference.  Much like swapping out phono cartridges, if you walked out of the room while it was switched, you may not realize what's different when you returned.  Would any of us say phono cartridges all sound the same based on that?  Many products in consumer are like that, requiring a very careful comparison and a educated listener.  @erik_squires , you are a very educated listener!.   

Working in this industry full time, where differences are a constant challenge in diagnosing problems in service (client heard something you cannot replicate) or assessing value of something new, you can be fooled but usually scinece wins.  Which is why we have a $10,000 Audio Precision sytem with calibrated mic to measure things.  The science behind active vs passive is conclusive and not debatable, unless you elevate your own perception as the superior test.  Demos are contextual audible comparisons with a tremendous number of variables.  For some, once their own perception is satisfied, even if inaccurate to science, they are happy and the search is over.  Sort of a parrallel to the way we prefer one color over another in a car-they really do look different in more ways than color alone.  And once we decide which color we like, we rarely look back. 

Ive said it before, I think active expands the ability to hear changes in the system of various cmponents, not reduces them.  All the elements before the active speakers are easier to hear, cables, preamps, turntables, sources, etc.  thqtq's certainly my expereince.   Sometimes it seems like the shared thought is "I'll buy active when you can pry my amp from my cold dead fingers".  It like the amp makers marketing has convinced everyone that its worth buying an expensive amp.  From a science point of view, passive being "better" than active is like telling someone from Arizona that snow tires are "better" on an all wheel drive sports car when you've only test driven them in the snow.  Snow tires may indeed work better in that one condition, but certainly not all.   Because you've never driven that car with snow tires in the summer on a dry road doesnt make it true.

Brad

I can say this, we get more calls about active now (regarding info on ATC as we are the importer) than ever before.  I think this bias against active is beginning to change.  Not that passive will go away, but some are beginning to want to scale down (a turntable/streamer, preamp and active speakers is nice simple system that has high WAF). or hear a pair of actives and like them better.  

Brad

HI @glai 

The SE uses all discrete amplifers, the best [sounding] amplifiers ATC makes.  More esolution, finer detials are more clear, etc.  

Yes ATC has made external amp actives for a long time.  IN the pro side they make the  SCM200 and 300- both use an external 3 channel power amp for each speaker.  There are tower versions of these for home using a different tweeter (ATC vs the AUdax super high power one for pro) but it still uses the P4 external amp/crossover package liek the pro version.  Tjhese sound great but use fans to keep cool so not the best for living rooms, bu better suited to a machine room where they can be remoted.  RIght now they make a 150LE that uses a 3 channel, passive cooled P6, with intergrated crossover, so this is an "external active" solution that functions the same as our internal active set ups.