Speaker Time Alignment Delays
*Important* All values given in the Delay column are in milliseconds (mS). Funktion One crossovers have the option to set the delays in milliseconds, millimetres & metres or feet (displayed on the crossover units as mS, mm & Mt and feet respectively). Make sure the crossover is set to milliseconds when the delay values are entered. If the crossover is set to metres this produces an error of about x3!
The correct crossover points, time alignment and limiter settings are absolutely essential to achieve perfect sound and the safe working of the system. If you cant find what you need here we are happy to give advice and work out custom setups for your system. We can also write special presets for you to load into the Funktion One XO or XTA DP series controllers.
The correct crossover points and time alignment settings are absolutely essential to achieve perfect sound and the safe working of the system.
XO2 and XO4 series Loudspeaker Management Systems are loaded with a range of settings from the factory.These presets can be found in the ''Crossover Only'' section of the Global Memory sub menu which can be accessed as follows:
If you cant find what you need in the controller or on the Settings pages here on the website we will be happy to give advice and work out custom setups for your system. We can also write special presets for you to load into the Funktion One X0 or XTA DP series controllers
If anything is unclear please email us
The crossover points are an integral part of our system design and the time alignment figures are a manifestation of the relative physical location of the devices. Great care and attention has been taken in arriving at these settings with regard to alignment, phase, location and the physical parameters of the drivers and waveguides themselves. Where a delay between an enclosure and a separate Bass speaker is quoted, the figure is stated assuming that the fronts of the enclosures are aligned.
System EQ? What system EQ?
There are no fixed inherent EQ settings for any of the drivers as these would degrade available headroom and phase coherence. We do not believe at all in fixing the loudspeakers' response electronically; we prefer to take the time to get the speaker design right as this is in keeping with our purist approach.
Frequency Band Drive Levels
Relative drive levels are dependent on the amplifier's through gain. For example: If a Resolution 2 is driven by two amplifiers (one for the 15'' Bass and one for Mid-High) with the same through gain then, as you will see from the settings page, the Bass will need to be run at +8 dB relative to the Mid-Highs. In the real world however the two amplifiers may not have the same gain. For example if an amplifier with a gain of 38dB is used for Bass and another with a gain of 36dB is used for Mid-High then the Bass will need to be run at +6 dB relative to the Mid-Highs to maintain the correct ratio.
Limiter settings, on the other hand, are dependent on through gain, sensitivity and the loudspeaker's power handling ability. The most important thing is that the amplifier should never be allowed to run into continuous clip. Clipping squares off the output waveform of the amp, sending distortion in the form of harmonics through to the voice coil, this creates heat which if it continues will burn out the voice coil. Effectively a small amp in clip is more likely to damage a speaker than a large amp running cleanly. To avoid this, the limiters should be set at least 1 dB below the amplifier's input sensitivity.
Of course setting limiters in this way does not make allowance for the fact that the amplifiers' power capability may exceed that which the speaker can handle. A suitable starting point would be to set the Bass limiters in the above way with each successive higher band being reduced by a further 2dB (assuming equal input sensitivities and gains). Therefore on a Resolution 5 four-way system, the HF limiters would end up being set at least 6dB safer than the Bass; (of course input sensitivity and gain have to be taken into account). The other factor at play here is how many drivers are connected to each amplifier channel. The lower the impedance of the load the earlier the amplifier will clip and therefore limiters should be set for the maximum number of drivers that will be driven per channel (the lowest impedance).
REMEMBER: The primary purpose of crossover band limiting is to protect the system from overdriving, sudden and unexpected high level signals and occasional larger than normal transients. It is not really intended to be used instead of compressors and therefore limit lights should not be flashing or on all the time. If a system is limiting heavily, audio quality and drive units will suffer. However, if set up carefully they can be used to ensure the system stays in its comfort zone, the frequency spectrum remains reasonably balanced and the maximum system level is controlled for aesthetic or environmental reasons.
Balanced sound ''On The Limit''
Here are a couple of normal scenarios.
1. You've got your mix set up and ''in the pocket'' then the singer gets a bit excited and shouts ''Hello (insert your town here)! Are we all having a good time??!'' His vocal compressor is set at a low ratio (or there isn't one) and you're not quick enough on the fader to catch the sudden burst of level. Happily your system limiters are set a couple of dB before the clip point of the amps in accordance with the power handling of the drivers and the amps don't clip.
2. A sudden burst of feedback from a vocal mic too near a side fill and the same thing happens.
3. An inexperienced guest engineer loses control of the mix and ends up running too loud, the limiters start flashing and we ask him to back off a bit, he's surprised that it actually starts to sound louder when the masters are pulled down a little and the limiters stop pumping (how many times have I seen this).
In all these cases the limiters are set for system safety and nothing gets broken, all good but what does the system actually sound like and how loud is it when the limiters come into play?
Mid and HF horns are usually more efficient than low mid and bass drivers. Of course they handle less power but you can often get a situation where if everything is just set for safety the system is capable of being driven into a state of imbalance where it sounds bad and can even be way too loud for the venue and the safety of the people in it. Bass speakers these days can handle a massive amount of power (as long as it's clean) so large amps are used and limiters set to stop clip from occurring. Mid and high limiters are set progressively tighter in respect to the drivers lesser power handling. It's still a good idea to use a large amp though. Transient spikes, totally valid to the music like the hit of the snare or cymbal crashes can get past the limiters and this is good because the dynamics and excitement of the music are preserved and these transients are not long enough to overpower the driver as long as they're not clipping. So what happens as the system comes up to full power. Often the bass will limit first, then as the system is driven harder the low mid starts to limit, the hi mids are still going strong as are the highs. If the bass limits 4 dB before the mid highs this is effectively the same as turning up the mid highs by 4dB, the balance of the system is completely wrong and all the hard work of tuning and sound check is wasted. The thing to do here is to tighten the limiters still further so that the mids and highs start to limit at around the same point as the bass. This way the frequency content of the music will be maintained when in the limiters, the mids stay at a level where they still relate to the low end. The settings for this will be different for live and club systems, you will want to leave a bit more headroom for the dynamics of live music. In a night club there may be noise restrictions or the owner may have an idea of how loud he wants the system to go. The principle is the same. In both cases run the system up to the required maximum level, reduce the limiters so that the limit lights are flashing then open up a dB or so to account for when the room is warm and full of people, come back later when the venue is running and fine tune if needed. Above all, lock the system to safeguard against tampering! Your system is now not only safe against damage, its also safe against being driven out of balance and sounding really bad.
Setting the Limiter
Now you may be thinking "So I know what to do when my system is running, but how should I set my limiters in the first place?". Good question; below is a conversion calculator that provides the maximum limit setting that should be allowed:
*Important: Your limiter setting should NEVER exceed this value (i.e. be made less sensitive) and neither should it be fully relied on to protect the system. The final responsibility lies with the operator, only the person who stands in front of the system can tell what is really happening.
If you stay within the power of the attached table, follow the notes above and tighten limiters further to set an acceptable level which sounds sweet, you will almost certainly find yourself turning some of the limiters down below the speaker's power ratings.
Once you have the system up and running the most important thing is to listen to the speakers, they'll tell you if they're getting too much power as they start to sound bad, generally a speaker will start to distort long before it actually destroys itself. If a bass speaker starts to "growl" then its reaching its mechanical limits and producing second harmonic distortion, so it needs to be turned down or limited earlier if you can't control the maximum level with the fader (ie if the DJ is "in control"...)
Another point is that digital crossovers need to be driven at the correct level to ensure maximum use of the resolution available because at low input drive levels fewer bits are used. Signal should be clearly visible on the input meters with the -6dB light flashing to get the best from the converters. Because Funktion One equipment is so intrinsically efficient (high conversion of amplifier energy into acoustic energy) we often need to reduce amplifier gain to achieve this. Signal to noise ratio will also be improved. A suitable amplifier input sensitivity to achieve this would be +10 dBu. If amplifier gain is reduced then limiters will need to be adjusted accordingly.
Many amplifiers have rear-panel or internal DIP switches to enable user-selection of input sensitivity which mean that this objective can be met whilst leaving the front panel gain control safely on maximum. A gain of 32dB is a good starting point, if you need to go for less then switch to 26dB.
*Warning* If the amp front panel controls are used to reduce gain and the limiters are reset to suit then great care must be taken not to turn the front panel gain control up again without re-adjusting the limiters. Crew or other operators must be made aware of this. In a 'dry-hire' environment it is probably not advisable to send a system out like this without locking the amplifier level controls to avoid unauthorised adjustment. If this isn't possible, then the sonic advantages may have to be forgone.