voltage requirements of true power

[Moble Enclosurs 10+ year member]

But when we start to talk about nominals, and rms values, etc, it is a p issing match because nothing is at max, and the variables involved are less sensitive to mechanical and thermal failure. You can essentially go below and above these points. It is the exact reason why xmech and xmax are different, and why rms, continuous, and peak are different. Not to mention that generalized percentages are then used as an acceptable means of proper operation of the driver......one might question one day, "is rms half the peak, or is it the power of one half of the peak?" Which one is it? If you google it, you will get different results, and different answers. Therefore, it is easy to conclude that xmax, and rms values are generalized. Which is why the manufacturer can use them, because it becomes relative to who operates the system and how, as well as what box is used, etc. Too many variables. But good estimations at that.

 

[Moble Enclosurs 10+ year member]

So, going back to those peak specifications, thos can be pretty accurate as long as the manufacturer measures it right during testing of the product. Rms is then "calculated". This means that we can use peak to our advantage.

So, 5. Peak power specifications can be used more precisely than rms values....which completely contradicts the other ways of utilizing proper power.

From this, I can hopefully, correctly determine the musical and peak voltage requirements of any driver on the market more accurately. And there are two ways I go about this.

Number 1: is determine a voltage requirement based on free air testing of the driver with a consistant impedance curve.

Number 2: I then match that voltage to the low frequency cutoff of the enclosure(as of now, only conventional reflex designs have been tested) while the sub is installed or loaded.

 

[Moble Enclosurs 10+ year member]

This allows you to determine the maximum possible voltage requirements of the speaker in case unloading occurs within the enclosure, and uses the cutoff point as a mechanical relation to excursion control to verify that any frequencies higher than that point allow for maximum power transfer.

The other portion of this formula, allows us to confirm the voltage requirements based on wiring configuration as well.

The relation of wiring resistance levels and voltage requirements is this: when resistance decreases, voltage requirements decrease...NOT voltage itself! With a consistant impedance curve, voltage needs to be regulated by use of gain levels, or even volume levels.

This is where the confusion may occur that gains have been in the past used as volume, when it is two different purposes. It is confused likely because they both regulate voltage. Other factors are involved that make the purpose of them different, such as WHERE the voltage is regulated, either from low level or high level output, and from what source, determining different points of distortion levels,etc. The biggest difference is that when gains are set, they do not move, and volume can be used as volume as it should.

So, number 6. Do not use gains as volume. Once they are set, they do not move unless different gear is used or switched, or added/subtracted.

 

[Moble Enclosurs 10+ year member]

So, with all of that said so far, we can figure for proper voltage with any setup, and utilize efficient power transfer from the amp to the driver, or the source to the load based on impedance and resistance levels to keep everything operating properly in any acoustical environment.

We also have to understand amplifier power ratings as well, otherwise this entire theory is null.

So, 6. We need to know how much power an amplifier is actually capable of. This can be tested out as well, using a resistor, or dummy load. I will not yet get into how this is done either without being able to show you pictures and/or video. But once the maximum voltage level of an amplifier is obtained, we can get the power levels from that amplifier as well.

One might ask, "how do I do all of this before I purchase anything?" Well, as far as the speakers are concerned, this can be done quite effectively with the formulas, but amplifier ratings can get a little tricky. But on the speadsheet will be a way to get safe voltage maximum levels as well.

As of now, I have tested 8 different drivers, full range to sub usage, 1" diameter to 12" diameter, with great results.

I have setup different configurations with multiple coils as well as multiple drivers(series, parallel, s/p) with great results.

Next, I will be posting those results on here with some details as to what was done. Pictures will be included as well.

 

[Phoenix Risen 10+ year member]

one of the only times ive actually wanted to read and focus on a thread in the tech section around here.

and for that i thank you.

 

[hispls 5,000+ posts]

Not sure where this is going, but I'm in for the ride.

 

[Moble Enclosurs 10+ year member]

one of the only times ive actually wanted to read and focus on a thread in the tech section around here.
and for that i thank you.

You're very welcome. Now, I want to share with you all an example that I just calculated for at work.......next post.

 

[Moble Enclosurs 10+ year member]

So, for my example, I research on the internet to find a driver that is out of the power ratings that I have tested so far....something that can handle more. I came up with using the RE AUDIOXXX15d2 driver. i will be using 6 of these wired to a 1.4ohm impedance for maximum power transfer from a low resistance amplifier, such as the common 1 ohm stable amplifier. Now, I do not recommend using too many drivers on a single amp, but for this example, I will only be simulating a single amp to power these beasts.

One thing to know about amps and power distribution is that there is a reason they are called amplifiers, and not voltifiers. Because when dealing with multiple drivers, such as this example of 6 15s, the voltage will be distributed equally to each driver, as long as they are all of the same resistance, such as in this example: each one is 4.2ohms per coil. So, giving my calculations for these, I came up with a musical voltage level of 38.53V and a peak voltage of 54.49V. In order to set this voltage correctly, I need to know the free-air resonance of the driver(s), which is 19.1Hz. So, this says that I can test this voltage out on these subs when not installed at 38.53V and they should not reach xmech or thermal limits and should play very efficiently. BUT, in order to do this test, I need an amplifier that will supply the power correctly.

One thing that many people do not look at when purchasing an amplifier is the amp ratings. The fuses can tell you what the maximum ampere levels the amplifier may be capable of in most good built amplifiers, but overall the construction of the circuits and the transformer usage within the amplifier will tell the tale of any amp. But for sake of not being able to open the amp up, or purchasing anything until something is known, we can use this fuse rating and the specifications of the amp given by the manufacturer as a reference, as we will have nothing else to go by unless we know of someone who has used the amplifier and tested its capabilities out that could inform you of its actual performance. We have no way around this dilemma, so we need to make the best of it.

So, using the figures of amplifier efficiency, we will not base it on wattage, as some car audio shops do, but more so the amperes that it can put out. This is a very important factor when knowing how an amplifier can provide power without damage. So, we will calculate the amperes needed for these drivers at 38.53V@1.4Ohms. For this, I come up with 27.518A. That is pretty good for 6DVC drivers rated at 2000Wpeak each. So, now we need to find an amplifier that will provide over 38.53V continuous without exceeding 27.518A, as this will cause heating issues with the amplifier and a high possibility of damage over time.

For this, I have calculated a final wattage of 1060.18W needed at this resistance level, because the 2000W each peak is likely tested at series connectivity to show its maximum power consumption. Manufacturers can use this to show high power handling capabilities. But once resistance is lowered, it requires less power to operate them efficiently. make sense? So, that is why only 1060.18W is needed for all 6 2000W peak drivers!

So, I need an amplifier that can produce the 38.53V@= 27.518A. Doing more research on this, I found on the same site, the xtx3000.1 amplifier to work with this configuration. The amp specifications state that it can produce 1400W@1ohm, which I found to be conservative, because I have calculated it to be around 1484.7W@1ohm, which will give us ABOUT 38.53A to utilize efficiently. So, far so good. But, what about @ our needed 1.4ohms resistance . We get about 31.623A of usage and a power distribution of about 44.27V, which gives us a wattage of 1400W@1.4Ohms, which the amp states that this can be done @1ohm. Pretty close to the manufacturer specs. So, these amps seem to be rated very well.

Now, if we hook the drivers up in a series/parallel/parallel connection, we get our 1.4Ohms from this, and we have an amplifier that can produce a max ampere level of 31.623A efficiently, and we only need 27.518A of that, as well as it having the capability to produce over our needed 1060.18W, which it will give us about 1400W to use. This amp will work well for 6 of these drivers in this configuration.

That is the example I have came up with so far to use, but not being able to test it, yet. I have a couple of JLW3 10s lying around and a kenwood amplifier setting in the foyer to possibly hook up to test everything out. As long as I calculate the kenwood amplifier to be able to match the subwoofers in output and amperes and wiring possibilities, then this can be proven soon.

Next post will be the other stage of the gain settings for the voltage levels of this example.

NOTE: Since this was an example, resistance is an example as well. Actual resistance can be calculated for different configurations if needed. Again, this is just an example.

 

[Moble Enclosurs 10+ year member]

Ill post the gain setting information next......I just wanted to state this as well to reference you in power levels........

Keep in mind that for this example, the reason only a 3000W amp is need to power (6) 15s that are capable of 2000W peak each, for a total of 12kWs is due to the wiring configuration and amp draw from the drivers. For example, If I were to wire them in a series/series/parallel connection, this will change EVERYTHING. And this amp may not be able to push them hard at all. In actuality, then resistance would be(from the example) 5.6Ohms, which would give us a needed 77.05V music, and a draw of 13.75A. So, the good news is amp draw decreases, due to the parallel connection in the second phase of the wiring into a series, creating a higher resistance, but you also will need more voltage to supply the drivers with the same amount of efficiency and power handling as the S/P/P connection@1.4Ohms. So, this means the amp needs to produce 77.05V@5.6ohms, and not draw over 13.75A. So, this amplifier of 3000watts@1ohm will provide us with 38.53A@1ohm. So, as long as we do not pass this ampere level, we can supply the drivers with enough power, up to the maximum power available, which in this case is 1487.7w@1OHM. So, as long as this amp can produce over 1060.18W at 5.6ohms, we are good. Well, this amp can produce only 1000W@2ohms it states, so, even though ampere levels are good, the amp will run out of power before it reaches 77.05V@5.6ohms. We would need an amplifier capable of producing over 1060.18@5.6ohms, which would be one of a rating of 12000W peak!. Because at efficiency levels, this will give us about 5950W continuous@1ohm, and very close to 1060W@5.6ohms. So, you see how wiring can affect how much power you need? Now, as long as this amp now, can produce the 1060W@5.6ohms under 13.75A, which it should or it would be a pretty inefficient amp at that point. This kind of amp if it could produce 12000W@1ohm peak would be able to give us about 77A of usage and the same for voltage if resistance of the amp is 1ohm stable at this rating.

AND...if the wiring is in all series connections, which would take a LOT of power to reach needed voltage at this point of 231.16V@50.4Ohms. This would require it to power each sub again at 1060.18 again to reach this voltage, and a total peak power rating from an amplifier of..............wait for it....................107,967.41Watts of power! This would give each sub, the need 1060.18W it requires@231.16V@50.4ohms. The crazy thing is.....this is possible. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif, But way to much needed. So, why not get an amp capable of 1ohm loading, and wire these at the lowest resistance to not go below 1ohm, and find an amp that can produce the voltage and amp draw to supply each sub with 1060.18W more efficiently? This is why low resistance is so popular. It can save you money in the long run.

 

[Moble Enclosurs 10+ year member]

So, now we need to use that voltage@Fs of the drivers in free-air, because remember, this so far has all been done WITHOUT an enclosure....and we need to incorperate it into setting gains with a DMM using voltage requirements when the subs are loaded. Now, When I set gains for my components, I do not use this...I use the oscope for finding distortion limits, etc. But this way is good for using only a DMM because you will not reach xmech or will get vary close to and over break-in time will reach xmax. SO, this is good for subwoofer usage but can be used for any driver in a conventional design so far.

So, in order to figure what we need to do with voltage, I have another formula as mentioned that figures for cutoff(this is not of my own figures, but a combination of other formulas that work well with physics--the first formula usage is my own). So, with the original example, lets say we want to put these drivers in about 24 cubic ft of internal volume, minus displacements. With this, I came up with a cutoff for this design of 11Hz! So, this means that with this voltage of 38.53V given in the original equations from the 3000W amplifier, we need to set the tone generator at 11Hz and set voltage @11Hz=38.53V. Now, those with subsonic filters may find this ineffective at this point. SO, what is recommended if the cutoff goes below the SSF frequency, to use the SSF cutoff point. This needs to be tested as I have no SSF to utilize yet for my amplifier. Also, I have to test further the effectiveness of the resonance of the driver vs the resonance or impedance spike(s) of the enclosure. I am posting a video soon of this in action. SO, as this is not fully tested yet, I cannot fully verify the enclosure gain matching for all situations until this is tested. Since enclosure tuning can effect impedance curves, I may need to rewrite this formula to include that as well, but not based on tuning frequency rather than impedance peaks, just as that of the free-air testing.

I can assure that without an SSF, in this example, that setting voltage at 11Hz will be goo, because at 11Hz, excursion is much higher regardless of tuning than that of a -3dB rating of cutoff. So, I know that this formula is effective, but not with SSFs yet. Updates will be done on this. but basiclaly, this is how it will be followed when setting voltage and matching subs with amps, etc. It will hopefully all work out in the end.

And a lot of this is common electronics calculations, but with some changes, as mentioned, for accuracy int he beginning to set the tone for everything done after. Ill be posting a short vid soon of this in action. Using free-air testing on different drivers, and also one with an enclosure gain setting.

And dont worry, pictures will be included as well, as requested when this gets further into it. As long as everything goes to plan. What has been mentioned so far, can be done by anyone, as long as the first part is known, which again, I may put in a spreadsheet....maybe.

 

[05trailblazer 10+ year member]

my brain is going nuts with all this info here! //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif i'll be posted for more updates!

 

[Moble Enclosurs 10+ year member]

So, I also just finished some initial testing on some TB tweeters I have lying around as well, the TB 25-1166sj. I have 4 of them to test out, and I just completed testing on a single one with max voltage and it was perfect! They have an Fs of around 900Hz, which I also ran through the WT3, and used that to test the voltage, which I calculated to be no more than 5.76V of musical power, and I fed it 5.167V(because one more notch up gave me over 6V-and I have 3 volume controls to use, lol) and it took it like a champ for more than 5 minutes on a test tone. Then matched it on some dubstep, and it was very crisp and clear. Test SAT on that as well. The only difference is, with this test, the tweeter backing is not considered an enclosure. Though if it were, it would give me a volume of .0123liters, and a cutoff of 2566.19Hz, which the manufacturer states 2000Hz is the lowest point it will play with minimal distortion, so I would put 5.76V@2566.19Hz if the shell was considered a "box". And I used 900Hz, so this seems to be more accurate to not use the enclosure style here.

More to come....plus that video(or multiple videos when I get the chance)...very busy. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif Hope you guys enjoy this so far. Nothing has been shown proven to you yet, but very soon, ok? I promise.

 

[Moble Enclosurs 10+ year member]

So, I also just finished some initial testing on some TB tweeters I have lying around as well, the TB 25-1166sj. I have 4 of them to test out, and I just completed testing on a single one with max voltage and it was perfect! They have an Fs of around 900Hz, which I also ran through the WT3, and used that to test the voltage, which I calculated to be no more than 5.76V of musical power, and I fed it 5.167V(because one more notch up gave me over 6V-and I have 3 volume controls to use, lol) and it took it like a champ for more than 5 minutes on a test tone. Then matched it on some dubstep, and it was very crisp and clear. Test SAT on that as well. The only difference is, with this test, the tweeter backing is not considered an enclosure. Though if it were, it would give me a volume of .0123liters, and a cutoff of 2566.19Hz, which the manufacturer states 2000Hz is the lowest point it will play with minimal distortion, so I would put 5.76V@2566.19Hz if the shell was considered a "box". And I used 900Hz, so this seems to be more accurate to not use the enclosure style here.
More to come....plus that video(or multiple videos when I get the chance)...very busy. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif Hope you guys enjoy this so far. Nothing has been shown proven to you yet, but very soon, ok? I promise.

Also, to add to this......this will give me about 7.07watts of power that ran this tweeter like a champ. Now, the manufacturer says it can go up to 50W@what I measured was 4.7Ohms, not their stated 3Ohms. At their 3Ohm rating, I would be around 4.6V@900Hz and still 7.07W that this tweeter will take. And at over 93dB efficiency, it gets quite impressive. I calculated its sensitivity at over 98dB, but they stated 93dB. I can tell you from personal experience with these tweeters, that they are very sensitive, so I am questioning their full specifications on this one. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[05trailblazer 10+ year member]

keep it going genious smexy beast lol //content.invisioncic.com/y282845/emoticons/2thumbs.gif.fdc3ba010dbb42b61704534b46d02fe4.gif

 

[Moble Enclosurs 10+ year member]

So, I had a chance to wire all (4) tweeters up as well, and got a voltage requirement of 9.54V.....tested and bingo. Same great results. I could not wire these in parallel because the amp I have for these frequencies will not hold up. So, it was tested with a FR of 180Hz-20KHz, and STILL they did not distort....so again test SAT.

Now, you notice, that when wired in series....the wattage does not change. This is a misconception among many audio enthusiasts and hobbiest that are just starting in the field, where they believe, if you wire series, you get less power, or if you wire parallel you get more power. No, the power distribution is equal to all drivers in the circuit. As such, even when all 4 tweeters were wired in series, the wattage remains at 7.07W per driver. SO, the confusion is with that vs total power, which is actually 28.28W (versus a single driver having a total power of 7.07W), but since we do not test this theory on wattage considering it is the constant (per driver), we use the changed parameters to verify accuracy, such as voltage and amperes. These are more important than wattage to the speakers.

Wattage is constant for any wiring configuration because what we want to know is how much a single driver can handle, and then distribute that to ALL drivers equally. And we control wattage usage by controlling voltage output at the amp. I just had to point that out.

Sooo, on to shooting the videos! I can only do what I have in front of me and Ill try to make them simple but effective. smexy.....out