Gezzza
20-10-2003, 03:27 PM
Taken from Alto Mobile (http://www.altomobile.com) website :)
Provided By Kevin O'Byrne - Alto Mobile Tech Support
EQ-ing Your Sound System
---------------------------
Whether you are a sound-off competitor, a professional installer or just someone who likes their music, you are not going to be able to create a really great-sounding system unless you know how the music should really sound.
The ancient art of listening hasn't changed much over the years; the problem is, most people hear but don't listen. The easiest and probably the best way to learn what music sounds like at source is to visit a local jazz club or cafe-bar where a trio of piano, bass and drums is performing live. Get close to the group and listen. Take in the sound of the piano and the resonance of the double bass; listen to the bass drum, the snare and the cymbals. Now all you need to do is recreate that live sound in a car.
Of course a lot of the music we listen to nowadays – particularly dance music - is purely synthetic, created by music and drum synthesizers, samplers and vocoders. Even so, knowing what sounds right in natural instruments will take you a long way towards reproducing the sound that the recording engineer mixed at the studio, because all the music we make – even purely electronic music – is inspired by the natural sounds that we find pleasant and stimulating.
High Fidelity means faithful, accurate reproduction of the recorded work - those whose audio systems play booming bass and shrill high frequencies have obviously never really listened to music. How well the system reproduces the instruments in the various frequency bands is vital. But which instruments should you be listening to when auditioning sub-bass, midrange, mid-bass and high frequencies?
Auditioning tonal balance
You will not be able to successfully setup a sound system unless you have experience of how a particular instrument should sound and which instruments are good for revealing strengths and weaknesses in a sound system.
Electric bass guitar provides a good pointer to the quality of the mid-bass reproduction. A system which lacks mid-bass will make the guitar sound as if it is being played behind closed doors in the next room (poorly defined), while one that lacks sub-bass will make it sound light and thin.
The snare drum is a particularly good instrument for revealing tonal balance across quite a wide range of frequencies. Its main output is in the region of 400-500Hz, but if mid-bass is lacking then the drum will sound thin and boxy. It's great for revealing a midrange that is sitting back or too far forward in the mix, and it can sound more like a tambourine if the mid-highs and high frequencies are wrongly equalized (often in an attempt to give more presence to vocals).
You'll often find midrange dynamics on the snare badly suppressed if the speaker is being asked to work too hard in the bass or mid-bass region. On the other hand, it's possible to achieve striking dynamics on the snare by boosting some of the frequency bands, but this can leave piano sounding thin and brash.
Synthesized bass (usually played on a synthesizer keyboard) is unusual because it can contain very low sustained frequencies – sub-bass of around 40Hz or below - but at the same time produce strong output much higher up the frequency scale. Although not a natural instrument, synthesizers can provide a very good guide to the tonal balance of a system because they are capable of a very steady output level across an unnaturally wide frequency range, but they need to be auditioned with care. The nature of electronic instruments makes them very variable. With a synthesizer, the aim of the musician and recording engineer is often to create an interesting new sound, so the sound will be heavily processed. Although natural instruments like piano and saxophone are also likely to be processed in the recording studio (to make them slightly brighter or to add reverberation), they usually retain their distinctive sound and this makes them a more reliable and consistent reference.
Classic analog synthesizer tones are popular when testing SPL vehicles (car audio systems designed predominantly for sound pressure level competition) since they are capable of producing low fundamental frequencies, heavy output through the sub-bass region and amazing dynamics. But for sound quality vehicles it is generally advisable to use piano or organ, which also span a wide frequency range but provide a more reliable reference. By the way, some church organ music contains frequencies lower than most synthesizers can produce.
Bear in mind that a lot of today's popular music sounds as if real instruments are being played, when in fact the natural instrument sounds are coming from sampling keyboards. These can sound extremely convincing and can be used to audition and setup your system, but sometimes the musical scope and processing extremes of these instruments can mislead you. But whatever music you choose to use, the key is to listen to a bunch of tracks on as many top quality sound systems as you can. That way you get to know just how good it can sound. Then the trick is to get it sounding as good or better in your own vehicle.
Vocals (male and female), piano and saxophone are favourite sounds for judging midrange performance. Because most of us hear people talking every day (and due to the natural sensitivity of our ears across this particular frequency band), it is relatively easy to hear when the vocals are unnatural (though it takes a little more experience to know how to fix it!).
The saxophone sound is beautifully rich in harmonics, tenor sax in particular, and provides an excellent indication of the system's performance in the lower midrange through to upper midrange.
Cymbals and other metallic percussion instruments tend to be best for revealing the performance of tweeters, but brass and wind instruments can be good for this too.
Once you know on which instruments to concentrate when auditioning a sound system, it's a case of listening to the music tracks as often and as carefully as possible, using a high quality home hi-fi system or known high quality in-car system. Then try to make them sound that way in your vehicle using the Alto Mobile Control 8 or Control 16 dedicated equalizers, or the Drive 20, Drive 30 or UCS PRO digital crossovers which all have powerful EQ sections.
TIPS for achieving a good tonal balance
** Choose your test/setup discs carefully, bearing in mind the points mentioned above. If you are entering one of the autosound contests for sound quality, always setup your system for the contest using the disc the judges will use.
** If competing in a sound quality contest, the judging will usually be performed while the vehicle is parked and without the engine running, so make sure the system is setup for this. Specifically, check that the level of bass is not too high.
** Check speaker crossover points and amplifier gain settings, and subwoofer cabinet size, build quality and vent dimensions.
** To avoid buzzes and rattles, make sure everything is tightened down - door mechanisms, window regulators, door release handles. Dampen down any loose trim.
Use sound deadening material or a spray-on treatment to prevent the larger metal panels of the vehicle from resonating, which can cause peaks to occur at certain frequencies. Treat especially the door skin, rear doors/side panels and the sides of the trunk.
** The tonal balance will often change with volume level and this is indicative of variations in speaker sensitivity, a poorly tuned bass system (check the vent size) or simply the non-linear response of the chosen system components (especially the loudspeakers). If you have access to a real-time analyzer (RTA) then measure the frequency response at the different volume settings to help you to pinpoint the problem. Adjusting the speaker crossover points (to create an overlap or widen the gap between adjacent drive units) can help to overcome speaker sensitivity variations.
Provided By Kevin O'Byrne - Alto Mobile Tech Support
EQ-ing Your Sound System
---------------------------
Whether you are a sound-off competitor, a professional installer or just someone who likes their music, you are not going to be able to create a really great-sounding system unless you know how the music should really sound.
The ancient art of listening hasn't changed much over the years; the problem is, most people hear but don't listen. The easiest and probably the best way to learn what music sounds like at source is to visit a local jazz club or cafe-bar where a trio of piano, bass and drums is performing live. Get close to the group and listen. Take in the sound of the piano and the resonance of the double bass; listen to the bass drum, the snare and the cymbals. Now all you need to do is recreate that live sound in a car.
Of course a lot of the music we listen to nowadays – particularly dance music - is purely synthetic, created by music and drum synthesizers, samplers and vocoders. Even so, knowing what sounds right in natural instruments will take you a long way towards reproducing the sound that the recording engineer mixed at the studio, because all the music we make – even purely electronic music – is inspired by the natural sounds that we find pleasant and stimulating.
High Fidelity means faithful, accurate reproduction of the recorded work - those whose audio systems play booming bass and shrill high frequencies have obviously never really listened to music. How well the system reproduces the instruments in the various frequency bands is vital. But which instruments should you be listening to when auditioning sub-bass, midrange, mid-bass and high frequencies?
Auditioning tonal balance
You will not be able to successfully setup a sound system unless you have experience of how a particular instrument should sound and which instruments are good for revealing strengths and weaknesses in a sound system.
Electric bass guitar provides a good pointer to the quality of the mid-bass reproduction. A system which lacks mid-bass will make the guitar sound as if it is being played behind closed doors in the next room (poorly defined), while one that lacks sub-bass will make it sound light and thin.
The snare drum is a particularly good instrument for revealing tonal balance across quite a wide range of frequencies. Its main output is in the region of 400-500Hz, but if mid-bass is lacking then the drum will sound thin and boxy. It's great for revealing a midrange that is sitting back or too far forward in the mix, and it can sound more like a tambourine if the mid-highs and high frequencies are wrongly equalized (often in an attempt to give more presence to vocals).
You'll often find midrange dynamics on the snare badly suppressed if the speaker is being asked to work too hard in the bass or mid-bass region. On the other hand, it's possible to achieve striking dynamics on the snare by boosting some of the frequency bands, but this can leave piano sounding thin and brash.
Synthesized bass (usually played on a synthesizer keyboard) is unusual because it can contain very low sustained frequencies – sub-bass of around 40Hz or below - but at the same time produce strong output much higher up the frequency scale. Although not a natural instrument, synthesizers can provide a very good guide to the tonal balance of a system because they are capable of a very steady output level across an unnaturally wide frequency range, but they need to be auditioned with care. The nature of electronic instruments makes them very variable. With a synthesizer, the aim of the musician and recording engineer is often to create an interesting new sound, so the sound will be heavily processed. Although natural instruments like piano and saxophone are also likely to be processed in the recording studio (to make them slightly brighter or to add reverberation), they usually retain their distinctive sound and this makes them a more reliable and consistent reference.
Classic analog synthesizer tones are popular when testing SPL vehicles (car audio systems designed predominantly for sound pressure level competition) since they are capable of producing low fundamental frequencies, heavy output through the sub-bass region and amazing dynamics. But for sound quality vehicles it is generally advisable to use piano or organ, which also span a wide frequency range but provide a more reliable reference. By the way, some church organ music contains frequencies lower than most synthesizers can produce.
Bear in mind that a lot of today's popular music sounds as if real instruments are being played, when in fact the natural instrument sounds are coming from sampling keyboards. These can sound extremely convincing and can be used to audition and setup your system, but sometimes the musical scope and processing extremes of these instruments can mislead you. But whatever music you choose to use, the key is to listen to a bunch of tracks on as many top quality sound systems as you can. That way you get to know just how good it can sound. Then the trick is to get it sounding as good or better in your own vehicle.
Vocals (male and female), piano and saxophone are favourite sounds for judging midrange performance. Because most of us hear people talking every day (and due to the natural sensitivity of our ears across this particular frequency band), it is relatively easy to hear when the vocals are unnatural (though it takes a little more experience to know how to fix it!).
The saxophone sound is beautifully rich in harmonics, tenor sax in particular, and provides an excellent indication of the system's performance in the lower midrange through to upper midrange.
Cymbals and other metallic percussion instruments tend to be best for revealing the performance of tweeters, but brass and wind instruments can be good for this too.
Once you know on which instruments to concentrate when auditioning a sound system, it's a case of listening to the music tracks as often and as carefully as possible, using a high quality home hi-fi system or known high quality in-car system. Then try to make them sound that way in your vehicle using the Alto Mobile Control 8 or Control 16 dedicated equalizers, or the Drive 20, Drive 30 or UCS PRO digital crossovers which all have powerful EQ sections.
TIPS for achieving a good tonal balance
** Choose your test/setup discs carefully, bearing in mind the points mentioned above. If you are entering one of the autosound contests for sound quality, always setup your system for the contest using the disc the judges will use.
** If competing in a sound quality contest, the judging will usually be performed while the vehicle is parked and without the engine running, so make sure the system is setup for this. Specifically, check that the level of bass is not too high.
** Check speaker crossover points and amplifier gain settings, and subwoofer cabinet size, build quality and vent dimensions.
** To avoid buzzes and rattles, make sure everything is tightened down - door mechanisms, window regulators, door release handles. Dampen down any loose trim.
Use sound deadening material or a spray-on treatment to prevent the larger metal panels of the vehicle from resonating, which can cause peaks to occur at certain frequencies. Treat especially the door skin, rear doors/side panels and the sides of the trunk.
** The tonal balance will often change with volume level and this is indicative of variations in speaker sensitivity, a poorly tuned bass system (check the vent size) or simply the non-linear response of the chosen system components (especially the loudspeakers). If you have access to a real-time analyzer (RTA) then measure the frequency response at the different volume settings to help you to pinpoint the problem. Adjusting the speaker crossover points (to create an overlap or widen the gap between adjacent drive units) can help to overcome speaker sensitivity variations.