got all my MDF, got all my glue got all my sealant, now i juts have one more question before construction starts.
I have an amp that puts out 170 watts at 8 ohms and 240 at 4 ohms.
If i wired the atlas with the coils in series,(giving me slightly less power), would it be worth it? im saying will the extyra BL and extra sensitivity esentially cancell out the lower amp power?
according to my calcs i should get 35 less watts at 6 ohms, and the increase in sensitivity, should cancell it out. Having a bit more moter strength would be nice too!
I have an amp that puts out 170 watts at 8 ohms and 240 at 4 ohms.
If i wired the atlas with the coils in series,(giving me slightly less power), would it be worth it? im saying will the extyra BL and extra sensitivity esentially cancell out the lower amp power?
according to my calcs i should get 35 less watts at 6 ohms, and the increase in sensitivity, should cancell it out. Having a bit more moter strength would be nice too!
I don't actually know the answer as to exactly what the efficiency will be but I think it's pretty safe to assume that if there is any difference in output it would be within a fraction of a dB and wouldn't be noticeable.
Go series. It almost always sounds better. The only time I have found parrallel useful is when I am trying to get the most spl I can.
You can't go parallel with the coils on Atlas subs.
The 2nd coil is 2 ohm and is made for adjusting the Qts of the driver.(see wiring tutorial on ascendant audio's website).
As another option it can be wired in series with the 4 ohm coil which affects the Qts only slightly but gives you a 6 ohm load.
The 2nd coil is 2 ohm and is made for adjusting the Qts of the driver.(see wiring tutorial on ascendant audio's website).
As another option it can be wired in series with the 4 ohm coil which affects the Qts only slightly but gives you a 6 ohm load.
Why would sensitivity or motor strength increase? DJNubz must have been using an amp that couldn't handle the lower impedance of a parallel connection. My experience has been that parallel wiring of woofers always sounds better with the reason being that you end up with 1/4th the Le vs wiring in series and the much higher Le. Multiplying the Le by 4 just slows down your woofer.
You will get less power and a higher damping factor, so the quality may be a bit better.
You can't parallel an Atlas because the coils have different resistances! It says so very clearly on Ascendant's site.
As for Le going down in parallel, well, the DC resistance goes down as well. It has no effect on driver frequency range. Fc is where R = X (X being reactance)
You can't parallel an Atlas because the coils have different resistances! It says so very clearly on Ascendant's site.
As for Le going down in parallel, well, the DC resistance goes down as well. It has no effect on driver frequency range. Fc is where R = X (X being reactance)
johninCR said:
But a series connection will always be easier for an amp to drive current-wise which could be an issue with many amps... however, series vs parallel discussion is kinda not relevant to the Atlas.
These Atlas subs certainly have many possibilities. So many wiring configurations, changing driver specs, they seem to model well for almost any type of enclosure. They also have XBL motors at about budget sub prices. (the magnets sure look small in comparison to Adire's though).
Really leaves me asking... is there a catch???
k first of all i know it cant be wired in paralell, bt if you read adires paper on DVC subs youll notice what im talking about(using both coild increases bl and sensitivity).
Apparantly it can also take more power in this mode, as youre using all 6 layers of the vc, not just 4.
So the general consensus seems to be, wire all 6 layers (series of course).
Thanks for the speedy replys!
Apparantly it can also take more power in this mode, as youre using all 6 layers of the vc, not just 4.
So the general consensus seems to be, wire all 6 layers (series of course).
Thanks for the speedy replys!
It can take the same amount of current. And we have the formula P = I²R. So as only R is changing, and it's a linear change, going from 4 to 6 ohms at the same max current gives a max power increase of 50%. This is, of course, assuming that there is still sufficient voice coil cooling provisions (vents and such) to handle the increase in heat, otherwise you will get an increase in max power, but not 50%.
nononon you dont understand, ok, powering the 4 ohm coil only(normal setup) is only using 4/6 layers of the voicecoil, when you put the 2 ohm coil in series, instead of just shorting or leaving open, means that you use ALL 6 LAYERS, incleaing bl, and i think sensitivity.
i'm no tech. but, wouldn't wiring a 2 ohm coil in paralell with a 4 ohm coil be like wiring a 2 ohm resistor and a 4 ohm resistor in paralell? in other words you would then have a 2 ohm impeadance load on amp? crippledchicken 🙂
You'd have a 1/(1/2 + 1/4) = 4/3 ohm total.
However, that's not the big problem... The big problem is that the coils would have different currents and each produce a different magnetic field.
However, that's not the big problem... The big problem is that the coils would have different currents and each produce a different magnetic field.
ah, i see thanks for explaining that for me. i knew how resistors worked in paralell but, wasn't sure about impeadances. thanks, crippledchicken 🙂
It's the same for resistance, reactance, and impedance
If you're thinking that it goes by the lowest resistance/impedance, I think you probably saw that said about a small resistance and a large resistance, where the large resistance was negligable... but 4 ohms is not negligable in comparison to 2 ohms.
If you're thinking that it goes by the lowest resistance/impedance, I think you probably saw that said about a small resistance and a large resistance, where the large resistance was negligable... but 4 ohms is not negligable in comparison to 2 ohms.
its not paralell though, im not talking about paralell, all im asking is if the extra motor strength or wiring the coils in SERIES will balance out the sensitivity? or will i get an advantage? i KNOW that when running both coils you have extra power handling and extra bl, but will extra bl all factors the same increase sensitivity?
I've pondered this question as it applies to the Atlas 12 (The Atlas 15 should be fairly similar). Unfortunately, I have yet to get a definitive answer on how to calculate Bl for both coils wired in series. My best guess is that Bl increases by a factor of 1.5 in this configuration, but that assumption produces a crazy low Qts value.
Anyways here are my numbers:
4 Ohm "Low-Qts" wiring for Atlas 12 (4 ohm coil driven, 2 ohm coil open):
Qts: .331
Bl: 11.7 (Published value)
USPL: 93.19 dB / 2.83V
SPL: 88.63 / 1 Watt
6 Ohm Wiring for Atlas 12 (Both coils in series):
Qts: .226 (Calculated from known and guesstimated value)
Bl: 17.55 (Guesstimated value)
USPL: 93.19 / 2.83V
SPL: 90.39 / 1 Watt
If this is right, series wiring gains you 1.76 dB sensitivity at 1 watt. If xstephanx's amp does indeed produce 205 watts at 6 ohms and 240 watts at 4 ohms, that difference amounts to about .7 dB of acoustic power. That leaves you with a whopping 1.06 dB gain in output, which puts you ahead of the game.
Now the bad news... the driver doesn't model all that great at a Qts of .226 . Vented enclosures will have a much higher F3 and sealed enclosures are pretty much out of the picture, so what you gain in efficiency you lose in bass extension - not great for a subwoofer.
Of course I could very easily be wrong. Everybody feel free to jump in and correct me! 🙂
Anyways here are my numbers:
4 Ohm "Low-Qts" wiring for Atlas 12 (4 ohm coil driven, 2 ohm coil open):
Qts: .331
Bl: 11.7 (Published value)
USPL: 93.19 dB / 2.83V
SPL: 88.63 / 1 Watt
6 Ohm Wiring for Atlas 12 (Both coils in series):
Qts: .226 (Calculated from known and guesstimated value)
Bl: 17.55 (Guesstimated value)
USPL: 93.19 / 2.83V
SPL: 90.39 / 1 Watt
If this is right, series wiring gains you 1.76 dB sensitivity at 1 watt. If xstephanx's amp does indeed produce 205 watts at 6 ohms and 240 watts at 4 ohms, that difference amounts to about .7 dB of acoustic power. That leaves you with a whopping 1.06 dB gain in output, which puts you ahead of the game.
Now the bad news... the driver doesn't model all that great at a Qts of .226 . Vented enclosures will have a much higher F3 and sealed enclosures are pretty much out of the picture, so what you gain in efficiency you lose in bass extension - not great for a subwoofer.
Of course I could very easily be wrong. Everybody feel free to jump in and correct me! 🙂
"You get a 6 ohm load. You are simply using the entire 6 layer voice coil in series, which works great. Wire two drivers like that together in parallel, and you get a 3 ohm load...
...The 3 and 1.3 ohm wiring options result in the same specs for the driver, which are nearly identical to the standard low Qts of a single 4 ohm voice coil being used."
Quoted from Chad Kuypers on soundillusions.net forum (owner of ascendant audio)
thread
...The 3 and 1.3 ohm wiring options result in the same specs for the driver, which are nearly identical to the standard low Qts of a single 4 ohm voice coil being used."
Quoted from Chad Kuypers on soundillusions.net forum (owner of ascendant audio)
thread
Sure, but I think it's the "nearly" in "which are nearly identical to the standard low Qts of a single 4 ohm voice coil being used" that's in question. Is .226 "nearly identical" to .331?
As I said in that thread, Qes and Qts can be derrived from formulas that include Bl, so if Bl changes so do they. The only unknown is how much Bl changes.
As I said in that thread, Qes and Qts can be derrived from formulas that include Bl, so if Bl changes so do they. The only unknown is how much Bl changes.
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