Haha, yeah like i don't know how to use a screw driver! LOL!!!
They are glued, and at the moment i don't want to risk breaking the fronts until i have too.
For the moment the user manual states;
SP-MXKC45
Type 3-way bass-reflex type
Speaker Unit Woofer: 16 cm cone × 1
Mid: 5cm cone × 1
Tweeter: 2 cm dome × 1
Power Handling Capacity 200 W
Impedance 6 Ω
Frequency Range 45 Hz - 22 000 Hz
Sound pressure level 87 dB/W·m
Dimensions 220 mm × 324 mm × 238 mm(W/H/D)
Mass Approx. 3.6 kg
Amplifier
Output Power 200 W per channel, min. RMS, driven
into 6 Ω at 1kHz, with no more than
10% total harmonic distortion
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That counts !
So you don't want to destroy that beautiful silver/grey plastic ?
Keep it! along with the secrets behind ...
About 15 minutes into the party, the fronts won't be the only thing broken. The magic smoke won't be from reefer. If anything is this much trouble to get apart there is a reason.
The cheapest 12" PA drivers you can get and a pair of piezos will give you more output, more reliably, than all this put together.
I disagree actually, The cheapest 12 inch drivers like an Eminance Alpha 12A is made imo to a lower standard than the two after market 15inch drivers in the Kenwoods, surprisingly they of a higher quality than expected.
A Piezo tweeter is no different than the 8ohm Horn loaded Piezo i have taken out of the Kenwood.
Speaker drivers blow often, its not usually the driver or its 'cheap' construction rather its the clipped signals being sent to the drivers that destroy them. If i can keep the signals clean there is a high chance the drivers will perform as designed.
Not true.
Drivers blow because they're being fed too much power.
Clipping is only one way of providing too much power. Another way would be to mash everything into the compressors, having no dynamic range. No clipping in sight, but drivers would still cook.
Would a 100w (continuous) 4ohm driver stand up to a bridged VZ5000 that was running at maximum unclipped output?
I don't think so.
Drivers blow because they're being fed too much power.
Clipping is only one way of providing too much power. Another way would be to mash everything into the compressors, having no dynamic range. No clipping in sight, but drivers would still cook.
Would a 100w (continuous) 4ohm driver stand up to a bridged VZ5000 that was running at maximum unclipped output?
I don't think so.
Er yeah i agree you can burn out speakers with too much power but people DONT!!!
A sound engineer certainly never runs his 'bridged VZ5000' at maximum into a 4ohm speaker... no he turns the volume down. A home HIFI enthusiast doesn't turn up the volume so loud that he pops his voice coils? (well some muppet probably has
)No what happens is people overload either a pre-amp, or a mixer, or both to create a clipped signal that gets amplified down the line and blows the driver.
I have a volume control, and i don't have to turn my amps up too max! In fact i don't want to turn the amps to max as the best sound quality comes when you have 'headroom' for transients in the music to be amplified without distortion.
The amps i will be using in this rig will be more powerful than the drivers could handle, true. But i wont be using the max output of the amps all of the time (if at all) with the aim to achieve the cleanest possible sound given the circumstances.
This is a drawing of the circuit, i believe it solves the issue of mismatched drivers.
Essentially the input signal is routed to a crossover that splits the signal into;
1. A Low frequency 1600W MAX @4ohm Amp, which is sent to two 15inch 800W @ 8ohm drivers connected in parallel. Giving a total impedance of 4ohm's, and MAX power each of 800W.
2. A Mid/High frequency 2 channel 300W Max @ 8ohm Amp connected to the Philips (100W @ 6ohm) and the Horn tweeter with HPF (unknown Watts @ 8ohm) connected in parallel, with the JVC (200W Max @ 6ohm) connected in series to the parallel circuit creating a total impedance of 9.4 ohms, and a max power of 62W, 45W and 190W respectively.
Any comments or improvement please let me know
This is a drawing of the circuit, i believe it solves the issue of mismatched drivers.
Essentially the input signal is routed to a crossover that splits the signal into;
1. A Low frequency 1600W MAX @4ohm Amp, which is sent to two 15inch 800W @ 8ohm drivers connected in parallel. Giving a total impedance of 4ohm's, and MAX power each of 800W.
2. A Mid/High frequency 2 channel 300W Max @ 8ohm Amp connected to the Philips (100W @ 6ohm) and the Horn tweeter with HPF (unknown Watts @ 8ohm) connected in parallel, with the JVC (200W Max @ 6ohm) connected in series to the parallel circuit creating a total impedance of 9.4 ohms, and a max power of 62W, 45W and 190W respectively.
Any comments or improvement please let me know
Let's assume your amplifier can really output 300 watts into 8 ohms on each of the two channels simultaneously.
To do that, the output voltage of the amplifier would be 48.9 volts
That voltage is dropped across the speakers connected to it as defined by ohms law and Kirchhoff law.
The voltage is in proportion to the resistances of the speakers (or parallel combined speakers) If you had two identical speakers in series, each would get 1/2 the voltage. Since you have non-identical speakers, the voltage across each will be different.
The easiest way to determine the voltage drop is to first determine the current flowing. The formula for that is
Current (in Amperes) = voltage / resistance.
48.9 / 9.4 = 5.2 Amperes
Now, the voltage across a the resistance of a the 6 ohm speaker can be determined
X = 6 * 5.2 Amperes
The voltage (X) will be 31.2 volts.
The voltage across the other two speakers (assuming they combine to 3.4 ohms as you are describing will be:
Y = 3.4 * 5.2 Amperes
That voltage (Y) will be 17.68 volts.
Note that the total voltage is 31.2 + 17.68 = 48.88 (if I had not rounded the various numbers, this total number would be identical to the voltage output by the amplifier 48.9.)
Now... we can calculate the wattage (power) being dropped by each speaker.
power (in watts) = voltage * current.
The wattage being used by the 6 ohm JVC is 17.68 * 5.2, or 91.93 watts.
The voltage across the other two speakers is identical, but since they are two different resistance, the current through them will be different.
Again, we can first calculate the current by using
Current = voltage / resistance.
Voltage = 17.68 / 8 ohms = 2.21 Amperes.
Voltage = 17.68 / 6 ohms = 2.94 Amperes.
Note that the total current through the paralleled speakers = 5.5166 (again, if I had not rounded most of these numbers, this would be exactly the same current as through the single JVC we have connected. Please pretend the math added up by rounding this up to 5.2 amps)
The wattage used by the philips is
17.68 * 2.21 = 39.07 watts.
The wattage used by the horn tweeter is
17.68 * 2.94 = 51.97 watts.
Note that the power is NOT evenly divided by the three speakers. Most of it is across the JVC. The remaining split unevenly between the two in parallel.
If the speakers were all exactly as efficient as each other, they would be playing at very different volume levels, since the watts are all different. Since you can 99.99999% guarantee they are not all exactly the same efficiency, it is completely unknown how loud each will be and which will reach its physical limits first. (I'd guess the horn-tweeter will burn out way before the others get even close to their power limits)
Until you know how to apply ohms law and Kirchhoff laws to your parallel/series combination of drivers, and know their relative efficiencies, it is impossible to predict how it will all last once you apply power to it and turn up the volume.
It is nowhere near as simple as you have drawn.
Joe L.
I see an awful lot of navel gazing about how to wire together a bunch of home stereo speakers.... for PA use in an outdoor venue.
A few questions:
- How many people are you "catering for"?
- How large an area are you hoping to cover?
- How loud do you want things to get?
- How much bass do you need along with that?
If the answer to any of the above is "large, big or loud" then you need to stop and have a long hard think. Or alternatively start preparing to be disappointed and likely embarrassed.
None of the gear mentioned above is going to be efficient. If you are luck some of those speakers will be 90dB/W, and driven to the point of failure will peak at 110dB @ 1m. If you have more than a room full of people, more than a few metres from the speakers it is going to be an awfully dull party.
If you get the phasing of the speakers wrong, not only will it not be loud, it will be totally insipid. Irrespective of what you do, you need to get your head around this.
I actually like the idea of using "retired home gear" for a party. A level of realism is required though. We had a "stereo party" amongst my friends many years ago, where "entry" to the party required you to bring your amplifier and speakers along.
We stacked up about 10 pairs of speakers with their own amplifiers, probably 1500W of amplifiers all up, give or take. Most of the speakers were 8-12 inch, which is probably about what you are trying to press into service.
Did it work? Yes. This lot was able to produce some serious SPL (definitley party / dance level) in a large living room. It would have probably struggled outdoors for anything more than a modest group and area.
So back to the questions above:
If you said "Yes" to any of:
- More than a few dozen people
- More than a patio sized area
- I want to dance like I am in a club
- I want bass and not just piercing midrange
Then my advice is to go looking for an awful lot more speakers. By a lot, I would be trying for a van full if you want to get serious.
If you do that, you can make this work well.
Is this logical?
- Hifi Speaker @ 90dB sensitivity (optimistic)
- PA speaker @ 100dB sensitivity (realistic)
To achieve similar SPL from home speakers will take 10 times the power, which is silly, as home speakers just aren't made for that sort of treatment.
Load up a stack of hifi speakers - and get the phasing of them right - you can benefit from better coupling and have a hope of getting decent SPL without things smoking or just stopping.
Have fun.
A few questions:
- How many people are you "catering for"?
- How large an area are you hoping to cover?
- How loud do you want things to get?
- How much bass do you need along with that?
If the answer to any of the above is "large, big or loud" then you need to stop and have a long hard think. Or alternatively start preparing to be disappointed and likely embarrassed.
None of the gear mentioned above is going to be efficient. If you are luck some of those speakers will be 90dB/W, and driven to the point of failure will peak at 110dB @ 1m. If you have more than a room full of people, more than a few metres from the speakers it is going to be an awfully dull party.
If you get the phasing of the speakers wrong, not only will it not be loud, it will be totally insipid. Irrespective of what you do, you need to get your head around this.
I actually like the idea of using "retired home gear" for a party. A level of realism is required though. We had a "stereo party" amongst my friends many years ago, where "entry" to the party required you to bring your amplifier and speakers along.
We stacked up about 10 pairs of speakers with their own amplifiers, probably 1500W of amplifiers all up, give or take. Most of the speakers were 8-12 inch, which is probably about what you are trying to press into service.
Did it work? Yes. This lot was able to produce some serious SPL (definitley party / dance level) in a large living room. It would have probably struggled outdoors for anything more than a modest group and area.
So back to the questions above:
If you said "Yes" to any of:
- More than a few dozen people
- More than a patio sized area
- I want to dance like I am in a club
- I want bass and not just piercing midrange
Then my advice is to go looking for an awful lot more speakers. By a lot, I would be trying for a van full if you want to get serious.
If you do that, you can make this work well.
Is this logical?
- Hifi Speaker @ 90dB sensitivity (optimistic)
- PA speaker @ 100dB sensitivity (realistic)
To achieve similar SPL from home speakers will take 10 times the power, which is silly, as home speakers just aren't made for that sort of treatment.
Load up a stack of hifi speakers - and get the phasing of them right - you can benefit from better coupling and have a hope of getting decent SPL without things smoking or just stopping.
Have fun.
Looking at the supplied original picture, I very much doubt "cleaning" has much priority, if any at all
Way back when I was a teenager I tried to set up stuff like this and it didn’t work very well. The problem is all of those different speakers have different sensitivities/efficiencies. Your small speakers might have a sensitivity of 85db, your big pioneers might be 95db and your big horn might be 105db (I am picking values so the math works out nice, I don’t really know what they are.) In this case, you would have to feed 1 watt to the horn, 10 watts to the big pioneer and 100 watts to the small bookshelf speakers in order for them to sound coherent. If you ran this set up with one power source and crossover, you would wind up with an incredible screaking tweeter, a little bit of base and no real midrange to speak of. Put any more power to it and the bookshelf speakers will probably just blow. If you really want to run this pile of speakers the best chance you would have is to get a separate amplifier with volume control for each different pair of speakers. Then you could continue to tweak the volume of each pair until it sound decent, but it won’t get very loud.
So what I would do if I were trying to pull this off would be to go to my local Craigslist and type in “Cerwin Vega.” Look for any pair of their larger speakers with at least a 12” woofer and you will get something that has 95-103 DB sensitivity, and will get very loud without falling apart. In my area there is a pair of RE 30s for $180 right now. You can probably find something for less than 200, or if you are lucky a cheap pair where the foam has fallen out, and a $30 refoam kit on eBay. If you are using a setup with the 2 amps you mentioned, connect one amp to the Vegas’ and one to the subs in the Pioneers, with just the low frequencies via the crossover. Take the rest of those speakers and use them for decoration only. It will get louder, sound better and have a lower chance of blowing up that way.
My 2 cents take it or leave it.
PS: If you take my advice, please do not set fire to the Cerwin Vegas I would hate to think I contributed to the destruction of a good pair of them.
So what I would do if I were trying to pull this off would be to go to my local Craigslist and type in “Cerwin Vega.” Look for any pair of their larger speakers with at least a 12” woofer and you will get something that has 95-103 DB sensitivity, and will get very loud without falling apart. In my area there is a pair of RE 30s for $180 right now. You can probably find something for less than 200, or if you are lucky a cheap pair where the foam has fallen out, and a $30 refoam kit on eBay. If you are using a setup with the 2 amps you mentioned, connect one amp to the Vegas’ and one to the subs in the Pioneers, with just the low frequencies via the crossover. Take the rest of those speakers and use them for decoration only. It will get louder, sound better and have a lower chance of blowing up that way.
My 2 cents take it or leave it.
PS: If you take my advice, please do not set fire to the Cerwin Vegas I would hate to think I contributed to the destruction of a good pair of them.
Thanks for all the replies guys, its good to see a thriving community on here willing to give input to a crazy little project of mine.... Big up your selves
J.L. spot on mate, thanks for all the calcs you provided, very interesting to see how the voltages change as the current passes through the circuit, but i think you nailed it on the head..... until you try you just dont know how it will all work.
Googlyone you bring up some good points that maybe i haven't been clear enough about, so let me try and address them;
The speakers are NOT attempting to cater for a large dancefloor, replace a set of PA's, or set any world records for dB's @ 1m..... let me paint you a picture
I have an old UPS truck with a window in the side that will be parked on a large salt flat for about a week in the Nevada Desert. Next to the van will be a 10ft by 20ft tent which will act as our living area during the festival. The speakers will be positioned against the side of the truck and we will DJ from inside by the window playing to no more than a few friends who will be chilling, dancing, playing, getting drunk at our camp.
A small Hifi would probably be sufficient to do this job, BUT i enjoy messing around with speakers and found a VERY cheap bunch that apart from being scruffy seem to be in perfect working order.
So the fun DIY part is to have a home HIFI on steroids at our camp, to go and buy some 'Cerwin Vega' speakers or anything PA related completely misses the point!!! I don't want some cheap PA rig gear (look back at my photos and you see those scoops, they all ran 18' Precision Devices drivers) what i want IS a big f**king HIFI, its more fun, its more suitable and its not trying to be something its not.
I will leave the record attempting dB's @ 1m attemp to these guy's!
Will this bunch of speakers work, maybe?
Will i end up blowing some of the drivers, almost certainly!
Will i have fun finding out, hell yeah!
Let me confirm again that i don't want a new, cheap, professional PA rig, what i want is a fun, slightly crazy, don't mind if it dies rig to be taken into a harsh environment for some party fun. The reason i am on the forum asking for your help is so i can prolong and maximise the time this little rig will live.
I hope this all appeals to the teenager in you? As i hope the whole point of this project will be to bring out the inner child in me and my friends on the Playa.
J.L. spot on mate, thanks for all the calcs you provided, very interesting to see how the voltages change as the current passes through the circuit, but i think you nailed it on the head..... until you try you just dont know how it will all work.
Googlyone you bring up some good points that maybe i haven't been clear enough about, so let me try and address them;
The speakers are NOT attempting to cater for a large dancefloor, replace a set of PA's, or set any world records for dB's @ 1m..... let me paint you a picture
I have an old UPS truck with a window in the side that will be parked on a large salt flat for about a week in the Nevada Desert. Next to the van will be a 10ft by 20ft tent which will act as our living area during the festival. The speakers will be positioned against the side of the truck and we will DJ from inside by the window playing to no more than a few friends who will be chilling, dancing, playing, getting drunk at our camp.
A small Hifi would probably be sufficient to do this job, BUT i enjoy messing around with speakers and found a VERY cheap bunch that apart from being scruffy seem to be in perfect working order.
So the fun DIY part is to have a home HIFI on steroids at our camp, to go and buy some 'Cerwin Vega' speakers or anything PA related completely misses the point!!! I don't want some cheap PA rig gear (look back at my photos and you see those scoops, they all ran 18' Precision Devices drivers) what i want IS a big f**king HIFI, its more fun, its more suitable and its not trying to be something its not.
I will leave the record attempting dB's @ 1m attemp to these guy's!
Will this bunch of speakers work, maybe?
Will i end up blowing some of the drivers, almost certainly!
Will i have fun finding out, hell yeah!
Let me confirm again that i don't want a new, cheap, professional PA rig, what i want is a fun, slightly crazy, don't mind if it dies rig to be taken into a harsh environment for some party fun. The reason i am on the forum asking for your help is so i can prolong and maximise the time this little rig will live.
I hope this all appeals to the teenager in you? As i hope the whole point of this project will be to bring out the inner child in me and my friends on the Playa.
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What I would do then is get as many pair of speakers - WITH AN AMPLIFIER AND VOLUME CONTROL EACH. (ideally built into the amp that goes with each speaker)
Run these off one commoned preamplifier.
This:
- Avoids all the mucking around with trying to build an active XO, which with random drivers will be extremely difficult to get even close to right without test gear
- Allows you to use the existing crossovers in the speakers
- Allows you to set individual volumes for each speaker, so that when the "master" volume is at max, all amplifier / speaker pairs are flat out, but none waaay into clipping.
- Allows you to individually get the phasing of the speakers right (run one speaker, and check the phases of each other pair against it - simply put them face to face and check the bass stays there!)
In this way you can relatively simply create a huge stack of home speakers, with matching stack of home amplifiers and the only fancy bit is a preamp with a buffer and a zillion outputs. In truth you can get away with one preamp and a whole lot of RCA's wired from its output. Whihc I think is more in the spirit of what you are after.
Each amplifier will almost certainly draw no more than a hundred watts (if you use cheap **** home amps) so your genset will happily drive an enormous stack of them. With a stack, if one bows up, so what?
Run these off one commoned preamplifier.
This:
- Avoids all the mucking around with trying to build an active XO, which with random drivers will be extremely difficult to get even close to right without test gear
- Allows you to use the existing crossovers in the speakers
- Allows you to set individual volumes for each speaker, so that when the "master" volume is at max, all amplifier / speaker pairs are flat out, but none waaay into clipping.
- Allows you to individually get the phasing of the speakers right (run one speaker, and check the phases of each other pair against it - simply put them face to face and check the bass stays there!)
In this way you can relatively simply create a huge stack of home speakers, with matching stack of home amplifiers and the only fancy bit is a preamp with a buffer and a zillion outputs. In truth you can get away with one preamp and a whole lot of RCA's wired from its output. Whihc I think is more in the spirit of what you are after.
Each amplifier will almost certainly draw no more than a hundred watts (if you use cheap **** home amps) so your genset will happily drive an enormous stack of them. With a stack, if one bows up, so what?
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