drumnbass.be forum » Production » Hardware » active or passive loudspeaker active or passive loudspeaker Author Post Azer Easy Player Registration Date: 15-11-2002 Posts: 747 Helpfulness rating:  The road to hi-fidelity One of the first recommendations offered to somebody wishing to set up a small home studio is to forget their hi-fi speakers and go out and invest in a pair of quality studio monitors. The term 'hi-fi speaker' is perhaps a misnomer, particularly when referring to the all-in-one package systems. While perfect for partying around the house, these units tend to feature a distinct lack of high frequency detail, a clouded mid range, plus an unnaturally hyped and boomy bottom end, all of which is in complete contradiction to their high fidelity banner. Decent studio monitors (and decent hi-fi speakers too) exhibit far less colouration that's prone to masking problem areas in your mix. The wonderful dynamic range allows you to hear the precise degree of compression you might be adding, and the notably flatter frequency response lets you make EQ decisions in good faith, rather than compensating for the inadequacies of your speakers. But watch out as you climb the quality stakes because the marked improvement in sound clarity can make everything sound good. Possibly too good. The art of mixing is all about creating an aural landscape by taking sounds and carefully placing them in the foreground, background and anywhere in between. The more clarity your monitors provide, the more detail you will be able to pick out in the background. Let's assume a lovely high-end pair of monitors allow you to make out the normally faint sound of a pin drop. What superb clarity! As the mastering engineer for the project, I query the client's inclination towards haberdashery only to learn the sound of the pin hitting the floor is supposed to be a major part of the song. Not a problem it would seem, as the studio monitors reveal the sound without a hesitation and so the album goes off for CD duplication. Now take the same mix and play it on a mediocre consumer hi-fi system. What a disaster! Without the same pristine clarity of the studio system, the pindrop effect seems to have been lost in the mix. Could our excruciatingly expensive, state-of-the-art monitors really have been lying to us all this time? It's this false sense of security that can arise when mixing on high-end monitors that has many engineers resorting back to their trusty middle-of-the-road Yamaha NS10Ms (or similar) as a reality check on how their mixes are likely to translate to the masses. This is especially crucial in nailing the all-important vocal balance to ensure it hasn't slipped into the background. It's like cruising down the musical freeway on a beautiful spring afternoon in your fancy exotic convertible with a magnificent mountain range stretching along one side and the glistening ocean on the other. The birds and bees are seen going about their business among the native wild flowers, and there's not a single cloud in the sky to rain down on your parade. Life in your studio with your flashy monitors simply can't get better! Now back in the real world of consumer hi-fi where the beautiful serenity has been replaced by a washed-out sky and heavy fog. Suddenly your focus is drawn to just keeping all the musical signposts visible. With high-quality monitors, one can easily make out the vocals, for example, even if they're sitting far back in the mix. However, a ghettoblaster just won't have the same level of detail and therefore it's crucial to have the vocal mix balanced just right, or your mix will steer itself off the road! When panning your sounds across the stereo field, keep in mind also that some of your intended audience's sound systems may not exhibit imaging as sharp as your own monitors. It may be necessary to exaggerate any panning to ensure the effect is noticed. Pay particular attention to any sounds sitting around the 11 o'clock and 1 o'clock pan positions (with 12 o'clock being the centre or mono position of the pan knob). Any slight stereo positioning can easily be lost among the true mono sounds in a mix. __ 12-05-2003 09:58 Azer Easy Player Registration Date: 15-11-2002 Posts: 747 Helpfulness rating:  Room to move The shapes and materials used in the construction of acoustic instruments heavily govern their tonal character, while the surrounding walls, floors and furnishings simply become an extension of the instrument itself by inducing deep resonances (so you get peaks and ringing in the lower frequency response) called modes (see diagram below). Each room sounds different, so establishing proper bass levels in your mix can be difficult. At the same time, delayed early reflections of mid to high frequencies interact with the direct sound to inflict comb filtering (sharp notches in the frequency response) that resembles a subtle, stationary flanger or phaser effect. If there's too much reverberation build-up, it's likely to mask the true make-up of the mix. As a result of the room modes and reflections, our near perfect monitors adopt an entirely different flavour once removed from the manufacturer's echoless testing facilities. Regrettably, the very room devoted to your studio operations, despite all its good intentions, can seriously tarnish the reputation of even the most elite monitors The motion of sound is best understood when compared to the action of waves in water. As soundwaves, they consist of series of high crests and low troughs of air pressure that ripple through the atmosphere. When two independent waves come together, there are interesting and important consequences. Two crests (or two troughs) will sum to become bigger and therefore louder. These waves are said to be in-phase. Should a crest and a trough interact, they are said to be out-of-phase, and subtract from each other, and if the waves happen to be perfectly equal in frequency and volume (amplitude), yet completely out-of-phase from each other, they'll cancel each other out altogether to leave no sound (see the When waveforms meet box above). Low frequency sound waves below 300Hz slosh around the room like water in the bath. When a frequency is emitted with a wavelength (distance between two waveform crests) that's precisely double the distance between two opposing walls, upon hitting the wall, the rebounding wave switches phase and meets up with the second half of the oncoming waveform perfectly in-phase to reinforce it. This is the known as the fundamental resonant mode of the room. Additional modes spaced further up the frequency scale, known as harmonics, occur at frequencies that are multiples of the fundamental. What were once proudly advertised as totally flat monitors are now looking considerably bumpy. Of course, a room is three dimensional so the calculations should include frequency values for all opposing walls, floor, ceiling and diagonals. This can be performed fairly simply using the mode calculator at www.mcsquared.com/metricmodes.htm. Irregular shaped rooms work best as they present plenty of modes to even out the overall response. On the other hand, a cube-shaped room (3m x 3m x 3m), or a room where the long walls are exact multiples of the short walls (5m x 2.5m x 2.5m) suffer the worst. While containing fewer modes, their peaks are spaced distinctively apart, plus each mode will be heavily reinforced by the soundwaves bouncing around similar distances. __ 12-05-2003 09:58 Azer Easy Player Registration Date: 15-11-2002 Posts: 747 Helpfulness rating:  Standing still Have you ever walked around the room to discover the bass sounding particularly heavy in one spot, while elsewhere there's a considerable lack of bass? This occurs with the way modal frequencies are bounced between parallel walls. Because their wavelengths are directly related top the room's dimensions, the point where there's maximum air excitation (due to the convergence of in-phase waveforms) occurs in the same places in the room, while elsewhere, conflicting waveforms will be cancel themselves out. The areas of perfect cancellation are known as room nodes, and are characterised by the areas completely lacking in bass, while the areas between the dead spots or nodes will peak at double strength, and are called anti-nodes. Check out how standing waves form using the 'both sides closed' model at http://home.a-city.de/walter.fendt/physengl/stlwaves.htm. From the animation, you can see how each harmonic introduces more and more nodes (and anti-nodes) at strategic places. As each node appears to remain stationary in the room, the term 'standing wave' is born. The potential tragedy when working within the space of a room node is innocently cranking up the EQ with zero effect due to the perfect phase cancellation at that particular frequency, only to discover your mix is bursting when played in a different shaped room. Likewise, being blissfully unaware of your room's natural resonances and anti-nodes, there's a good chance you'll be EQing these frequencies out of your mixes, only to have your tracks sound disfigured when played in another venue. All is not lost All this talk of modes, nodes and anti-nodes sounds more like something from a sci-fi novel than a relaxed music studio, and thankfully there are ways to minimise their effect. The ultimate would be a custom designed room with an angled ceiling and non-parallel walls, but for starters, be sure to not position your monitors up hard against the walls, and especially away from corners, as this tends to reinforce the room modes. For persistent standing wave issues, specially tuned Helmholtz resonators, or bass traps, are available and they can be installed along walls and corners to soak up the problem frequencies before they get a chance to rebound and mess with the direct waves. This will serve to provide a more accurate frequency balance in the listening position. Up and above 300Hz, the wavelengths are too far short for modes and standing waves to be of any noticeable concern, and the focus turns to reflections and tiny echoes that we recognise as reverberation. This may be treated using acoustic tiles along walls opposite the speakers and anywhere there's a direct reflection from the speakers to your ears. There's no need to get carried away with treating the entire room. Acoustic tiles are only effective above 1,000Hz, so eliminating these frequencies altogether will leave you a room that's decidedly lacking in high frequency detail and a notably muddy bass response due to the remaining modal influence. Balance is the key. Your best weapon against problematic room acoustics and individual monitor traits is by simply knowing how your speakers sound in your personal studio space. Listen to all your favourite CDs through your monitors. That's the results you're striving for from your own mixes. Having an active awareness of the acoustical room influences will undoubtedly help your mixes translate to the wealth of different playback systems. FM __ 12-05-2003 09:59 Azer Easy Player Registration Date: 15-11-2002 Posts: 747 Helpfulness rating:  Horizontal vs vertical? Should your monitors sit on their sides, or upright? After years of sighting Yamaha NS10Ms lying horizontally across meter bridges of top recording studios pumping out Number 1 hits (and even more absolute flops), does it really matter which way your monitors sit? A couple of points against horizontal placement: ? Having the tweeter positioned close to hard surfaces, such as a table, shelf, or your mixing desk, can generate delayed reflections of the mid to upper frequencies. Recombining the slightly out-of-phase reflections with the direct sound can cause sharp notches or dips along the frequency response that resembles a comb, and hence the term comb filtering. ? If you sway from side to side in front of a vertically aligned box (ie, tweeter over the woofer), the distance the sound travels from both drivers to your ears remains unchanged for a wide sweet spot. When the box is on its side, it's common for you to be positioned closer to one driver than the other. Where the two drivers overlap and share sounds around the crossover point, the separate soundwaves combine slightly out of phase from each other. With a 3kHz crossover point, the wavelength will be around 11cm. This means if one driver is heard from a point that1s 5.5cm further away than the other, the entire frequency will disappear due to wave phase cancellation. Incidentally, some manufacturers recess their tweeters into the cabinet for better acoustic alignment with the woofer. ? If you're mixing with horizontally positioned monitors, ensure they're swung around to face you rather than firing straight ahead to maintain consistent driver-to-ear measurements. ? Placing the speaker box horizontally so that the woofer and tweeter are side-by-side risks the frequencies shared by both drivers (around the crossover point) arriving at the listener's ear at different times. This can result in a dip or notch at that frequency due to cancellation of the non phase-aligned waveforms. ? Placing the box vertically so the tweeter sits directly above the woofer encourages the shared frequencies to reach the listener in perfect phase alignment, How much power? Check the specifications for a set of passive speakers and note the sensitivity rating, for example: 89dB@1wattRMS /m. This means the speaker will output 89dB at a distance of 1m with just a single watt RMS of power. Not bad considering the recommended safe listening level across eight hours is 85dB. To achieve the slightest perceivable increase in volume (+3dB), double the amplifier power as shown below... 1 watt RMS = 89dB/m 2 watts RMS = 92dB/m 4 watts RMS = 95dB/m 8 watts RMS = 98dB/m 16 watts RMS = 101dB/m 32 watts RMS = 104dB/m 64 watts RMS = 107dB/m 128 watts RMS = 110dB/m 256 watts RMS = 113dB/m As you can see, a whole lot of amplification is required for not a lot of volume gain. So if 1W will happily output around 90dB, why do we need more? Music is full of ultra-fast transients that call upon additional power for the briefest of moments. Bass requires substantial power to accurately pump such massive volumes of air, and an amp working well within its limitations is likely to outputting lower distortion, noise, and a cleaner output. When deciding on an amp, look for the more realistic RMS power. Between 80-100W RMS per channel (or more) is ideal for nearfield monitoring. In fact, having up to double the amplifier power than the speakers are rated is much healthier than underpowering your speakers to the point of clipping where the amplifier1s maximum output is exceeded which resulting in flattening off the tops and bottoms of the audio waveform. __ 12-05-2003 10:00 Azer Easy Player Registration Date: 15-11-2002 Posts: 747 Helpfulness rating:  Safe monitoring levels A quality studio monitoring system will rarely reveal signs of stress and therefore it can be particularly difficult to judge its true loudness. Our ears naturally succumb to loud noise by backing off their sensitivity in what is known as a 'temporary threshold shift'. This causes us to no longer hear faint sounds. It's a natural form of compression, if you will, brought on through the fatigue of the muscles that operate within the inner ear. As the sensitivity diminishes, we're inevitably tempted to crank up the volume pot to compensate, and only exacerbate the problem. Whenever you suffer any hearing numbness or ringing (tinnitus) after being subjected to a sudden, loud noise, or noise built-up over time, it's a sign that damage to the ear has occurred. Fortunately, in most cases, our ears are able to repair themselves and should return to normal following several hours of rest, but the threat of permanent damage is a lingering concern. Music, in all its dynamically fluctuating glory, across an eight-hour exposure period is best kept below an average of 85dBA. An SPL (sound pressure level) meter (available from an electronics hobby shop) can help you establish safe monitoring levels. If it saves your sense of hearing for the long term, it may be the best musical investment you ever make. Troubleshooting If you've got problems with your monitors, before you rush off to pay someone else to fix them, see if it's a problem you can possibly work round yourself... Poor bass response, exaggerated stereo width, and a hollow mono image? Check your (passive) speaker connections for correct polarity. If the wires are reversed on one speaker, its audio phase is thrown180 degrees out from the other speaker. This forces one speaker cone to push forward, while the other speaker pulls back. This leads to soundwave cancellation immediately between the two speakers because one driver is sucking the energy away from the other. Amazingly enough, this is a common problem amongst audio-related shops that should really know better. No sound? If a speaker stops working, first check its connections, then swap it with the other speaker to ensure there's not a problem with the rest of your system. If it's a single driver within the speaker that's cut out, a wire may have worked loose internally, or the fine wire that makes up the voicecoil may have burnt out and will require a full driver replacement. Cracking sound at low volumes? Swap with another speaker to confirm fault is speaker related. When a speaker is overdriven, the voicecoil can heat up and distort until its molten insulation begins to rub against the inner surface of the magnet. A slight, even press against a suspect woofer driver diaphragm can confirm this if its movement feels gritty rather than smooth. The only solution is to replace the driver and watch the levels! Cleaning A gentle wipe over the cabinet with a clean cloth slightly dampened with water should be all that's needed to maintain your monitors' showroom shine. You can safely wipe over the woofer too if it's plastic and rubber surround. Be wary of touching the delicate tweeter diaphragm. Steer away from even the mildest detergents that can leave residues that may build-up and destroy the surround or other components over time. Recovering dented dustcaps and diaphragms Young (and old) children seem to love pushing their fingers into undesirable places. The woofer dustcap's sole purpose is to keep, you guessed it, dust from entering the voicecoil and magnet assembly, while a tweeter's domed diaphragm is purely built for sound. It's possible to suck dents out using a vacuum cleaner, but be sure to set it to its lowest power setting with the hose vent opened slightly to reduce the pressure. Why were you touching it anyway?! Jargonbuster Active: Used to describe processing that involves powered electronics, rather than relying on existing power. Active speaker systems use electronic crossovers to divide the full spectrum signal into bass and treble (and sometimes midrange) frequencies prior to powering separate, dedicated drivers. In direct comparison, passive crossovers use frequency-dividing filters that rely on the electrical power of the music signal itself to function. Hertz (Hz): The term named after Heinrich Rudolf Hertz (1857-1894) used to describe the pitch or frequency of an oscillating wave by counting the number of cycles (ie. the completed motion of a waveform crest followed by a trough) that occur in a second. The healthy human ear can detect soundwaves ranging from around 20Hz to 20,000Hz. Frequencies above 1,000Hz may be abbreviated to kilohertz (kHz), so 3,000Hz equals 3kHz. Phase: The position of a waveform at any given point of time in relation to another point, such as its stationary rest position or another waveform. Imaging: The ability for a pair of speakers to reproduce the precise position of a sound within a stereo sound field. Ideally, sounds should appear from pinpoint locations from imaginary positions between the two speakers. Unfortunately, due to inaccuracies in the stereo signal path, the recording medium, effects processing, amplification, crossovers, and even the drivers themselves, the perfect left and right waveforms can become disfigured to result in a stereo image that is blurred and indistinct. Tweeter: The smallest driver in a speaker system. It is capable of vibrating the air at a very fast pace, from around 2kHz to over 20kHz, that's 20,000 times per second! Woofer: The biggest driver in a speaker system and is used to handle frequencies from anywhere between 20Hz and 3kHz, depending on size and design. Dedicated bass systems (below 120Hz) are called subwoofers. Incidentally, the term 'subsonic' actually refers to a speed less than that of sound, so a more correct term to describe sounds that fall below that of audibility would be infrasonic or the infra-woofer, but I can't see anyone adopting my cause just yet! Greetz Azer __ 12-05-2003 10:01 Surya The Robot Registration Date: 04-11-2002 Posts: 11,238 Helpfulness rating:  Azer! __ "In dnb you should make people jump not swim" - Pieter Frenssen 2004 12-05-2003 10:13 thechronic admin Registration Date: 01-11-2002 Posts: 5,293 Helpfulness rating:  Lol infra-woofer I've read this before, is it coming from the sound on sound or something? Nice article!! __ If you find spam on the site, please hit the button and select my name. I'll personally kick it to the murky depths of hell where it belongs! 12-05-2003 11:22 Azer Easy Player Registration Date: 15-11-2002 Posts: 747 Helpfulness rating:  quote: Originally posted by thechronic Lol infra-woofer I've read this before, is it coming from the sound on sound or something? Nice article!! can't remember where i've got it from, pasted it once in a .doc __ 12-05-2003 11:38 Scion The Noize Squad Registration Date: 03-03-2003 Posts: 406 Helpfulness rating:  Yeah, thx for the info Azer, very nice to know my ears are going down , but now I at least know how not to damage them more __ Power to the peaceful 14-05-2003 15:28 Surya The Robot Registration Date: 04-11-2002 Posts: 11,238 Helpfulness rating:  Bought these today http://www.alesis.com/products/monitor1_mk2/index.html Got 30% off. ¤361 for a pair... Mackies were more like ¤1200 for one unit... that 'll be my next stop These are nice to fill in the gap for the moment, couldn't afford more. Sound nice, altho the freq respondce is only 45hz -> 20khz Will need a seperate sub to get full sound... __ "In dnb you should make people jump not swim" - Pieter Frenssen 2004 14-05-2003 23:15 thechronic admin Registration Date: 01-11-2002 Posts: 5,293 Helpfulness rating:  Good choice! Those are real classics and sound very good for the price! Now don't blow them! Get a quality poweramp, then they will last longer __ If you find spam on the site, please hit the button and select my name. I'll personally kick it to the murky depths of hell where it belongs! 14-05-2003 23:16 Surya The Robot Registration Date: 04-11-2002 Posts: 11,238 Helpfulness rating:  My Technics SU-V300M2 (2x 110W) will have to do for the mom... but I'll whach out with those babies, I'm planning on getting some money for them when I buy them Mackies __ "In dnb you should make people jump not swim" - Pieter Frenssen 2004 14-05-2003 23:20 Azer Easy Player Registration Date: 15-11-2002 Posts: 747 Helpfulness rating:  quote: Originally posted by Surya My Technics SU-V300M2 (2x 110W) will have to do for the mom... but I'll whach out with those babies, I'm planning on getting some money for them when I buy them Mackies lol, what happend to your pref for B&W __ 15-05-2003 11:29 Surya The Robot Registration Date: 04-11-2002 Posts: 11,238 Helpfulness rating:  quote: Originally posted by Azer quote: Originally posted by Surya My Technics SU-V300M2 (2x 110W) will have to do for the mom... but I'll whach out with those babies, I'm planning on getting some money for them when I buy them Mackies lol, what happend to your pref for B&W Still there, but still no cash Want B&W's for listening an Mackies for producing But I think thats for a very distant future I guess __ "In dnb you should make people jump not swim" - Pieter Frenssen 2004 15-05-2003 11:57 Azer Easy Player Registration Date: 15-11-2002 Posts: 747 Helpfulness rating:  quote: Originally posted by Surya quote: Originally posted by Azer quote: Originally posted by Surya My Technics SU-V300M2 (2x 110W) will have to do for the mom... but I'll whach out with those babies, I'm planning on getting some money for them when I buy them Mackies lol, what happend to your pref for B&W Still there, but still no cash Want B&W's for listening an Mackies for producing But I think thats for a very distant future I guess yeah, if you look at the price-tag its like i think i'm going to play the lottery from now on __ 15-05-2003 12:28 Surya The Robot Registration Date: 04-11-2002 Posts: 11,238 Helpfulness rating:  Man! They sound like 10x better here then they did in the shop. Niiiiiiiiiice! Much better than the ones I just blew up! I'm glad I did that Hope I can keep these till I have enough for the next ones __ "In dnb you should make people jump not swim" - Pieter Frenssen 2004 15-05-2003 16:40 thechronic admin Registration Date: 01-11-2002 Posts: 5,293 Helpfulness rating:  quote: Originally posted by Surya Man! They sound like 10x better here then they did in the shop. Niiiiiiiiiice! Much better than the ones I just blew up! I'm glad I did that Hope I can keep these till I have enough for the next ones Glad you're so happy with them They might not sound as good as the b&w's you wanted so badly but they will prove much more useful So now you're going to finish off all your tracks I guess? __ If you find spam on the site, please hit the button and select my name. I'll personally kick it to the murky depths of hell where it belongs! 15-05-2003 17:28 Surya The Robot Registration Date: 04-11-2002 Posts: 11,238 Helpfulness rating:  quote: Originally posted by thechronic quote: Originally posted by Surya Man! They sound like 10x better here then they did in the shop. Niiiiiiiiiice! Much better than the ones I just blew up! I'm glad I did that Hope I can keep these till I have enough for the next ones Glad you're so happy with them They might not sound as good as the b&w's you wanted so badly but they will prove much more useful So now you're going to finish off all your tracks I guess? Ofcourse they lack the power in the lower parts that more expencive speakers have, but I'll manage for the moment As soon as my PC is up and running properly again (XP reboots every time I want to delete or save a file - It's not a virus and it's not my ram, have to sort it out next week) than I'll gladly return to producing, hopfully with better n tighter soundz! __ "In dnb you should make people jump not swim" - Pieter Frenssen 2004 15-05-2003 17:48 spliffrider Member Registration Date: 18-03-2003 Posts: 62 If I'd have the money; I'd go for the mackie actives in no time... 300watt+150watt with them blue leds. It's really really VERY pure when u hear them pounding in yer ear... Definately top class deejay monitoring material; U can hear everything! __ 17-05-2003 10:24 worm Producer Registration Date: 07-07-2003 Posts: 20 Helpfulness rating:  quote: Originally posted by Scion Biggest difference: An active speaker has got a build-in amplifier, while passive speakers need an external amplifier. that's pretty much the only difference. active are going to cost you much more but are much less of a hassle (no amp or speaker wire is needed). quote: Originally posted by thechronic Genelec is not very much suited for dance music thechronic, with all due respect (cause i love the site and your expertise) but where did you hear this from? music is music man. i have had my 1030's for almost 2 years now and they have made ALL my mixes/mix-downs very pleasurable. side note: just my personal experience and advice. using 2 different monitoring devices (ex: mackie and genelecs; or ns10s and alesis) comes in real handy when trying to make your mix sound good all round (club, car, headphones, home, etc etc). __ -worm d p r e c o r d i n g s . c o m 08-07-2003 02:36 Pages (3): « previous 1 [2] 3 next » drumnbass.be forum » Production » Hardware » active or passive loudspeaker