Please advise on x-over setting for my High and Low speakers
Jeff S.
Posts: 22
Chapter 2.
Hello again all. I have established the basic hardware connection plan, finished a rough-draft setting for the x-over, and can adjust the Gain Setting of the entire system whenever I change anything that affects it. Basically, I’m having a blast. The next step as I see it is to decide on an “optimum x-over setting� given the gear and purpose I have. Could I have some “advice and council on x-over settings� please? Here is the situation:
Classic Rock / dance / party band playing out in the local clubs and bars. No keys or synth (yet), 4 vocalists, guitar cabs mic’d, bass DI to the board, drums mic’d. We have “Middle Of the Road� (MOR) gear as per Gadget, and we want to get it all sounding as good as we can get it. Here is the FOH hardware:
Mixer
DriveRack PA setup as “Mono-Sub with Stereo Tops� – 2x3
One Crown XS 700 Power Amp running one Peavey SP218 Sub-woofer box in Bridge-Mono (4 Ohms)
One Mackie M1400i Power Amp running two Yamaha S115V Full-Range cabinets (8 Ohm Stereo)
Peavey model SP 218 specs as follows:
Transducer complement: 2 x 18" woofer, vented
Usable low frequency limit (-10dB point): 40 Hz
Sensitivity: 99.0 dB SPL (@ 1W, 1m)
Maximum SPL (1 meter): 130 dB continuous, 136 dB peak
Box tuning frequency: 36 Hz
Minimum recommended active x-over freq and slope: 90 Hz at 18 dB/octave
High Pass Filter at 35 to 40 Hz with a 12 to 24 dB/octave roll-off is recommended
Yamaha S115V specs as follows:
Transducer complement: LF: 15" cone, HF: 2" V.C. driver
Sensitivity: 99dB SPL (1W, 1m)
Whether or not I really believe the SPL data published for the subs, those numbers are what they printed.
The following sections in the DRPA were turned OFF to start the x-over hunt:
GEQ, Sub-harmonic Synth, Compressor, PEQ, Delay, Limiter.
The x-over was initially roughed-in as follows to get started:
Low @ 40 Hz with a BW18, 100 Hz with a LR24, Gain = 0 dB
High @ 100 Hz with a LR24, Gain = 0 dB
Before just asking “what setting should we use for the x-over�, here is what I’ve done so far:
After playing with pink noise, listening to full-range music thru the systems, observing meter LEDs, looking at the speaker specs, and using my ears, I ended up with the same frequency spots and filter types as above, but with +5 dB gain in the Lows and -5 dB Gain in the Highs.
After the +5 / -5 dB Gain setting tweak with speakers plugged in and amps up, the 100 Hz +/- 40 Hz “warble track� from the Audio Test CD sounded reasonably OK I suppose (at the lower volumes needed since the rehearsal space is rather small), and CD music sounded OK, but I really don’t trust my ears for this task yet.
I haven’t had a chance to hear the band thru it in a real venue, so my current x-over settings are still a BIG unknown at the moment.
I follow that the x-over freq’s might need to change when the Gains are changed to maintain balance thru the x-over reigon, but I haven’t changed my freqs yet – they are both still @ 100 Hz but with different Gains. Gadget also said that he “generally ... adds gain in the sub region of the crossover�. So, how do you plan the adjustments of the x-over freqs when the x-over Gains are set to something other than 0 dB in the Highs and Lows? I presume the trained ear is the final judge, but is there a rough estimate or rule of thumb to start the process out?
OK, now I’ll ask it: “Given our gear and purpose, what would be a reasonable recommended x-over setting?�. I will smile and LMAO if I have stumbled onto it – or something close to it. Not likely, but even the blind pig finds the acorn sometimes � After that, what are the general strategies that lead us here – i.e. answers to the questions in the previous paragraph.
Not trying to sweat the small or unimportant details, just trying to wring out all the performance I can get from my MOR gear and understand the process. After the x-over is sussed out, I’ll get on with the next items of the setup.
- Jeff S.
Hello again all. I have established the basic hardware connection plan, finished a rough-draft setting for the x-over, and can adjust the Gain Setting of the entire system whenever I change anything that affects it. Basically, I’m having a blast. The next step as I see it is to decide on an “optimum x-over setting� given the gear and purpose I have. Could I have some “advice and council on x-over settings� please? Here is the situation:
Classic Rock / dance / party band playing out in the local clubs and bars. No keys or synth (yet), 4 vocalists, guitar cabs mic’d, bass DI to the board, drums mic’d. We have “Middle Of the Road� (MOR) gear as per Gadget, and we want to get it all sounding as good as we can get it. Here is the FOH hardware:
Mixer
DriveRack PA setup as “Mono-Sub with Stereo Tops� – 2x3
One Crown XS 700 Power Amp running one Peavey SP218 Sub-woofer box in Bridge-Mono (4 Ohms)
One Mackie M1400i Power Amp running two Yamaha S115V Full-Range cabinets (8 Ohm Stereo)
Peavey model SP 218 specs as follows:
Transducer complement: 2 x 18" woofer, vented
Usable low frequency limit (-10dB point): 40 Hz
Sensitivity: 99.0 dB SPL (@ 1W, 1m)
Maximum SPL (1 meter): 130 dB continuous, 136 dB peak
Box tuning frequency: 36 Hz
Minimum recommended active x-over freq and slope: 90 Hz at 18 dB/octave
High Pass Filter at 35 to 40 Hz with a 12 to 24 dB/octave roll-off is recommended
Yamaha S115V specs as follows:
Transducer complement: LF: 15" cone, HF: 2" V.C. driver
Sensitivity: 99dB SPL (1W, 1m)
Whether or not I really believe the SPL data published for the subs, those numbers are what they printed.
The following sections in the DRPA were turned OFF to start the x-over hunt:
GEQ, Sub-harmonic Synth, Compressor, PEQ, Delay, Limiter.
The x-over was initially roughed-in as follows to get started:
Low @ 40 Hz with a BW18, 100 Hz with a LR24, Gain = 0 dB
High @ 100 Hz with a LR24, Gain = 0 dB
Before just asking “what setting should we use for the x-over�, here is what I’ve done so far:
After playing with pink noise, listening to full-range music thru the systems, observing meter LEDs, looking at the speaker specs, and using my ears, I ended up with the same frequency spots and filter types as above, but with +5 dB gain in the Lows and -5 dB Gain in the Highs.
After the +5 / -5 dB Gain setting tweak with speakers plugged in and amps up, the 100 Hz +/- 40 Hz “warble track� from the Audio Test CD sounded reasonably OK I suppose (at the lower volumes needed since the rehearsal space is rather small), and CD music sounded OK, but I really don’t trust my ears for this task yet.
I haven’t had a chance to hear the band thru it in a real venue, so my current x-over settings are still a BIG unknown at the moment.
I follow that the x-over freq’s might need to change when the Gains are changed to maintain balance thru the x-over reigon, but I haven’t changed my freqs yet – they are both still @ 100 Hz but with different Gains. Gadget also said that he “generally ... adds gain in the sub region of the crossover�. So, how do you plan the adjustments of the x-over freqs when the x-over Gains are set to something other than 0 dB in the Highs and Lows? I presume the trained ear is the final judge, but is there a rough estimate or rule of thumb to start the process out?
OK, now I’ll ask it: “Given our gear and purpose, what would be a reasonable recommended x-over setting?�. I will smile and LMAO if I have stumbled onto it – or something close to it. Not likely, but even the blind pig finds the acorn sometimes � After that, what are the general strategies that lead us here – i.e. answers to the questions in the previous paragraph.
Not trying to sweat the small or unimportant details, just trying to wring out all the performance I can get from my MOR gear and understand the process. After the x-over is sussed out, I’ll get on with the next items of the setup.
- Jeff S.
0
Comments
The Horn/driver as I said is another problem altogether... There are tools we can buy to make this easier,(we have recommendations) but if we don't have any money to throw at the problem we CAN still figure it out... the woofer can reproduce some of the frequencies the horn can... like 2Khz, so if you feed a normal polarity 2khz to the known woofer orientation, and a reverse polarity 2khz frequency (reverse the +/- on the horn amp... you can use both channels of the FR for this purpose) to the horn ... if it's normal polarity some cancellation ogf the 2khz is apparent.
The cables can all be tested with a cable tester (again, we have recommendations) or a meter. but a reverse polarity cabe anywhere in the system (even the mic cables) can wreck havoc on the overall sonics of the system.
Crossovers are a very complex subject and just know that the internal passive crossover in the Yammies is minimalist at best. The addition of another amp and a bi-amp tops scheme will take your system to a whole new level of performance. That process can be found here:
viewtopic.php?f=60&t=1081
but I digress...
The trick here... the thing we are trying to do, is minimize the interaction in the crossover region. Remember that it doesn't matter if the xover gain is changed or the amp gain, the xover point is affected either way. There is an acoustical crossover point and it usually is divergent from the electrical one. Here is where I usually interject that "The more you learn, the less you know"...That said crossover theory will twist your brain into buit sized little pieces so suffice it to say the more complex the type.. the more "happens" to the signal in the crossover... the higher the number the steeper the slope and usually the less the interaction in the crossover region. Conversely the lower the number the less complicated and the more interaction in the crossover region.
Each xover type has it's own characteristics and were designed to provide specific benefits. Sometimes a slight spread in the xover points helps to minimize the interaction, this can also be helpful with regards to changing xover points as we adjust the gains of the various components. The real way to do this is with some FFT (measurement system that takes into consideration more than just frequency based volume like the RTA does) (and I know you will probably eventually move to this direction... you just seem like that kind of guy...) but again we don't have that available to us. Back to crossovers, as I said we might get better results with a slight spread in the xover points...this usually helps but you might need to use a PEQ for some Some crossover point equalization.
Sometimes some overlapping of the crossover point can elicit the best results...Here Butterworth filters with slopes of 18db and up are typically deployed, and are considered more "musical" for this purpose. JBL is one of the more prominent practitioners of this method.
Which ever xover type you use, the Driverack makes it pretty simple to experiment, and that costs nothing but your time. How far you choose to take system measurement is entirely up to you. But after it's all said and done what sound right to you is right... because one mans nirvana is anothers sonic hell (or something like that...).
This is largely due to differences in efficiency, and amp gain, but again without the tools to do this properly it's difficult to quantify. Perhaps if you downloaded the GUI and played with the different modules... and the crossovers yo would get a better Idea what were talking about here.
Did you go to this site?
http://www.lenardaudio.com/education/06_x-over.html
I bet you haven't been to the Study hall yet either?
http://www.prosoundweb.com/studyhall
These sites may help quench (for the time being) your thirst for knowledge.
There is nothing wrong with where you have ended up.. so start laughing
bring it...
G
My biggest question is: Can I do any damage by playing with the crossover points? Or, At what point do I approach damaging my system?
I have 2 PV115's running through a Crown XLS802
and 1 PV118 running through a Crown XLS202 Bridged Mono. The 118 shows a crossover frequency of 150 Hz. I don't know what that means but, it's a starting point.
I changed my Low Pass XOver to 150 & my High Pass to 150. I've made the BW (?) setting to where there is a dip at the point of crossover.
Does this make sense or is there more I should consider?
I love your comments that this can squirrel your brain. I certainly believe it. It is still great reading. Thanks for any help!
Now "your typical music" (good solid low end) dial the "hz" setting down until the trash goes away. By trash, I mean any simblance of vocals, guitar, etc. Just any thing that doesn't sound good.
My guess is somewhere between 90 and 110hz is where you'll end up. The vocals and mids will sound best (from your tops) if you stay closer to 110hz, the subs best if you stay closer to 90hz. Having said all that, I like 100hz.
DRA
PS - feel free to start a new thread. helps avoid twisted up threads.
No it won't cause any problem moving the xover point between the subs and the tops around, as long as you don't start clipping the amps or go lower than the 3db down point of the tops and crank the amps to clipping...
Yes start a new thread please for further questions.
Gadget
But, I appreciate the help, you guys. Makes me feel like I don't have to be so fearful.