Good question.
Pros:
better driver integration with active phase control
more efficient (no power loss in a crossover)
lower IMD distortion
Cons:
less tweakable
less gear to covet
less resale market |
Aktchi
You need to go bsck earlier in the thread - I list the pros.
Active speakers is not the same as putting a single passive amp in a box. For example the Woofer will be driven by a separate amp of say 275 watts, the mid range is driven with a separate amp of 100 watts and the tweeter is driven by a separate amp of 50 watts.
There is no power loss in a crossover (these get hot).
There is way less IMD distortion (the worst kind of distortion and most audible) because different frequency ranges are driven by completely separate circuits instead of one amp connected to as many as three drivers and two crossovers covering 20 to 20,000 Hz (which all interact and feedback into eachother). You can precisely control phase and driver integration way better than using passive cross overs.
There is a difference - it ain't simple moving the external power amp and placing it in the box. |
Tim916, Interesting article. I knew that IMD distortion was much lower in active speakers but I did not know that the difference was HUGE (for those who do not know ....IMD or intermodulation distortion is the worst kind of distortion and it has absolutely no relation to the music at all) Because the amplifiers in an active loudspeaker system are only required to operate over reduced frequency bands the intermodulation distortion products present in a passive system will be dramatically reduced, by typically 20dB, in an active system. This might be a bit of marketing hype (from ATC). However, the fact that the biggest market in audio, by far, is in passive speakers and separate amps (and ATC sell these to) would suggest this kind of marketing would go against greater sales volumes. |
IMD just does not sound at all like music. It is the complete opposite to harmonic distortion such as you get from mechanical drivers and clipping of tube amps (which can sound pleasant and may be totally indistinguishable from actual music...in short a matter of taste)
IMD happens when you have two signals intermodulating...say for example you have a woofer which is playing a kick drum or bass guitar playing with copious amounts of energy required at 85 Hz. Inevitably any transducer has inertia or mass (recall damping factor) and the amplifier is always fighting to keep the cone in the correct position. The effort placed on the amplifier is taken up by the power supply. Slight variations in power supply voltages due to an over demanding draw on current in the LF may affect reproduction of higher frequencies by the amplifier. (Typical challenges for an amp would be a reflex port designed to increase bass extension that causes a huge and sudden drop in impedance at a specific frequency...worse case might be a port at 85Hz on a small monitor with amazing bass sound or that reviewers describe as sounding like a bigger box speaker!)
The net result is that the simulataneous reproduction of the 85 Hz signal and a 1000 Hz signal (with natural harmonics of 2000 Hz etc and up) may cause the amp to output 1000-85, 1000+85, 1000-(2*85), 1000+(2*85) Hz etc. These sounds are totally unrelated to anything musical and sill stick out like a sore thumb (even if they are 20 db or more below the main signal levels)... at the very least they raise the noise floor but more often then not it means the mid range lacks clarity or sounds positively distorted in extreme cases. Simply turn up your amp until it clips heavily and you get the idea (in the extreme of course).
Better mid-range clarity, less harshness and an effortless sound is how I would describe a reduction in IMD distortion. (It is probably the reason that huge amps with massive power supplies are so popular even with modest speakers. It may also explain why horns are popular and known for dynamics and clarity - as they are generally an easier load on the amp. It may also explain why active subs are popular....by taking the heaviest load away from the main speakers' amplifier you get better clarity in the mids and there is a tendency to play music louder because it sounds sweeter or less harsh even at higher levels.)
Unfortunately, a single driver also suffers from amplifier induced IMD as the amp is still driving the sound across a broad range of frequencies and therefore difficulties caused by an impedance drop or difficult load at some frequencies may cause amplifier strain and IMD distortion in higher, more critical frequencies of the mid range.
However, any speaker that presents a very easy load to the amp such as a compression horn will likely benefit from less IMD.
Speakers with extreme bass extension (tuned reflex ports for bass enhancement) usually provide a difficult amplifier load and simply trade off great bass performance for less mid range clarity. This may explain why some veterans in the audiophile world will shun passive speakers with amazing bass extension down to 20 Hz in favor of a better mid range sound with less bass...there are two camps it seems on this particular point and a single driver limited range speaker is definitely in the camp of prefering better mid range sound at the expense of extremes in sound reproduction. An active three way is essentially like having three single driver speakers except that each of the three drivers operate over a very much narrower frequency range where reproduction may be optimized and where amp stress in music reproduction at certain frequencies (especially LF) will remain constained (through active filters and physical separation from other drivers) in a much narrower band; the end result is that it is much less audible (none of this is rocket science and this has been well known for decades, however, active speakers remain mostly relegated to professional applications so the "cons" continue to out weigh the "pros" in the audiophile world) |
I must admit I'm afraid to ask you the time for fear of discovering how a watch works. I am an Engineer and also studied heavily Physics at College ...fortunately I took a great job rather than the PHD scholarship in my final year....I might never have escaped academia and probably would never have been able to afford a hi-fi hobby if I had stayed there! Opening things up, reading text books, and trying to understand how things work in every detail is what Engineers and Physicists tend to do. Of course, understandably, it makes most people YAWN and turn away. So go ahead and YAWN! Thomas Dolby "She Blinded me with Science" seems to capture the Jekyl and Hyde personality that Engineer's must struggle with all the time; on one hand deeply feeling the emotion (in this case music) yet on the flip side (get pencils and calculator out) it is all just tubes and wires, biology, geometry, machinery...
"Good heavens Miss Sakamoto - you're beautiful!"
I -
I don't believe it!
There she goes again!
She's tidied up, and I can't find anything!
All my tubes and wires
And careful notes
And antiquated notions
But! - it's poetry in motion
And when she turned her eyes to me
As deep as any ocean
As sweet as any harmony
Mmm - but she blinded me with science
|
I agree with Bob...my comments should be taken as "technical Advantages" and not "Sonic Superiority Advantages"....what is sonically superior (i.e. sounds best) is so often a personal choice...so let's not go there!!!! |
i mention this because so called "accurate" active monitors, may be more inaccurate than one believes. Absolutely! Active monitors and all speakers are almost always the least accurate component in most high end systems. Speaker accuracy is orders of magnitude worse than most electronics and digital sources. Electronic signals can travel through 100's of amps in mixing boards etc. and hundres of feet of wires on teh way to the end user and yet the accuracy can be very well preserved....speakers are simply not in the same league....good point! Only headphones come close to the accuracy of modern electronics...but then the sound is inside your head and how realistic is that??? |
the issue seems to be panels vs cones rather than active vs non active speakers. Ah yes that could be a whole other thread. A two camp battle I suspect. My comments are restricted to the advantages of active acoustic suspension speakers over conventional passive two way, three way and four way acoustic suspension designs or basically any system where the amp is working all the way from 20 to 20Khz to drive a transducer...that is all. |
Forget it, no ME I know of uses active speakers. Some Mastering engineer's have used Actives...Bob Ludwig, George Massenburg, Doug Sax, Gavin Lurssen, Frank Wolf, James Guthrie ...some of these guys have multiple Grammy's....or some kind of tech awards. For example Brothers in Arms 20th Aniversary Edition won a Grammy for best surround sound and was both mixed and mastered on active speakers. So although you may not know anyone who uses active speakers for mastering there are some that do. I would agree that many use conventional speakers (passive). just in the same way that most consumers use passive speakers....but it is not fair to imply that nobody uses them for mastering, as some industry heavy weights certainly do or have in the past. |
Steve, Wow that is an awesome equipment list. I would be delighted/comfortable with almost any of the gear you listed. My only point was that some Mastering Engineers do or have used Active speakers rather than none (as "forget it" sort of implied to me). I stated earlier that "I would agree that many [Mastering Engineers] use conventional speakers (passive). " , which you just proved with a long list of illustrious ME's with impressive passive speakers - so I think we are in both in agreement. This is great - we agree and no need for me to add many more Active speaker users to a list as you have done (on passives) as I am not trying to prove that everyone uses Actives...I agree that a great many do not. As for Quoting Bob Olhsson: "The right level of monitor resolution for the job is very important... ...you can go crazy with perfecting sound to the point that it gets in the way of the musical performance." Well I had to laugh, since Bob Olhsson uses DunTech Sovereigns ... I mean hardly an ordinary run-of-the-mill circuit city speaker - I mean these are up there with some of the best speakers ever made! Please share any other anecdotes you have from the pro world, as I really enjoyed reading about it and hope that others did to. (I am an ordinary consumer with no music industry affiliation and yes I get most of my limited knowledge from reading rags like Sound on Sound etc. , user lists etc., AES journal etc. I do not personally know any of the people I referenced.) BTW: I finally found pics of your gear (Zu Druid setup) on another thread - that looks absolutely awesome too - wow! Like Ghasley, I am a little surprised to find the Zu's being used for this purpose but clearly you are aware of the limitations and use a sub when necessary and yours do not use standard tweeter networks. (No doubt you are a "Guru" at this stuff) |
Steve,
Thanks for taking the time to offer a lengthy reply. I agree with your comments about pro monitors - indeed they tend to be unforgiving, controlled accurate but limited bass extension, and harsh sounding with some playback material (especially hyper-compressed pop music, for example). Your comments are a fair assessment of potential drawbacks of pro monitor use in the home.
Apparently Dog Sax still uses his brother's designed tube EQ system!!! He listens to each track once or twice and then writes down the EQ settings he wants to use - then he goes through the whole thing one more time adjusting the EQ settings at the start of each track and makes a master. (He does not mess with EQ settings within the tracks) Essentially anything Doug does has gone to analog domain and then back to digital. He uses very little compression 1 or 1.5 db or so....which means most of what he produces retains the quality of the dynamics from the recording studio (now we know why his masters always sound good or at least natural). The tubes are probably used to sweeten the sound a bit....give the kick drum more punch for example.
A very good example of his work appears to be the re-masters of the first three Aerosmith albums...a HUGE improvement on what was previously issued.
This stuff really belongs to another thread, however, I thought I would share it. I have come to realize that you can only do so much with audio reproduction gear and you run into diminishing returns quite quickly.....at some point the quality coming out of the recording studio, mix and mastering becomes, by far, the biggest variable.
Indeed, I am astonished that audiophiles care so much about gear and yet seem to pay so very little attention to who is responsible in the studios for the sound production!!! I mean this is like building the most expensive chefs kitchen and then not caring where you buy your meat and vegetables!!!! Often a simple kitchen and simple recipe with great ingredients can suffice....
After selecting an artist or genre, the next thing I look for on a CD is the producer, mix engineer and the Mastering Engineer! If I don't like the crew I don't buy the CD!! Conversely, if I like the ME, such as Doug Sax, then I will be much more likely to buy a CD on a whim - even if I don't like the artist, at least it will have great sound! |
Genelec 8050A and the PMC AML1 Excellent choices to audition, IMHO. Incidently, I believe George Massenburg chose the Genelec 8050A for near field monitoring in perhaps one of the most amazing and "on the bleeding edge" studio projects I have ever come across. (I think I have some photos somewhere - it all looks rather impractical, impossible to clean but an amazing unique project nonetheless) |
Genelec 1032As and a 1094 Sub. An awesome setup. Of the really high end pro studio monitors Genelec seems to have less crossover to audiophile market than ATC - not sure why. ATC, Quested and Genelec invaded the US starting some twenty five years ago and replaced many of the older horn systems as main monitors in the highest end studios (at last loud could also sound good - not just a PA speaker). Genelec also garnered a respected position early on for near fields in most studios. Can't think why Genelec and Quested never made much of a dent in the audiophile market, as ATC has done. Perhaps it has something to do with "nice" and "accurate" simultaneously? Or the Pink Floyd affect? Or Genelec simply do not provide the requisite audiophile wood veneers? I'd be interested in your perspective. |
Chuck,
What you say makes sense and matches my observations too. Active designs are a hard sell outside the pro world or outside of cheapo computer satellite speakers. People just don't understand the tremendous advantages in separating the audioband and reducing IMD distortion from hard to drive bass frequencies. Since a lot of the practices are based on long standing tradition it will take time to change.
The PF reference is to David Gilmour's Astoria studio and to James Guthrie's Tahoe Studio...if you read Sounds on Sound or Mix magazine then I am sure you can get info on the speakers they use...even a google will probably find these details. |
I am curious about ATC though. I wonder how much improvement there is. As with everything there is diminishing returns at the higher end, YMMV. The bigger active ATC's will certainly play louder and cleaner and that is for sure...the shock and awe and the "you are there" factor is amazing compared to anything else I have heard (it sounds completely effortless at any volume). However, if you listen to light classical at modest volumes then many are totally content with the two way ATC SCM Active 20's (despite in theory that the biggest benefits of active tend to come in spades when you use a three way and separate that nasty power hungry woofer from the delicate mid range where your ear is so highly sensitive to IMD distortion). So if you like music for its dynamics and shear exhilaration (as well as all the other audiophile qualities) then I would say the bigger active ATC's are worth it. If you live in an apartment or don't care for realistic live sound levels then forget it - like an F1 car in downtown traffic most of your investment will remain under exploited. If you check the client list and history you will see that bigger active ATC's got their success as big studio main monitors used to impress the socks off of clients (musicians)... |
Tuffgong,
Nice description. I agree with you that this kind of sound is not for everyone. I only recommend these kind of studio active designs for those who profess to want accuracy and faithful reproduction of the source. Of course, most people believe that this is what they want and your point about increased frustration over badly mastered recordings is one of the reasons "laid back sound"is actually a better choice for many (actually they are really looking for something that makes as much of their music collection sound sweet, warm and nice....syrup and no fatigue) |
