Zilch's AK Design Collaborative - Econowave Speaker

[Zilch]

The parts list specifies components for different LF driver impedances.

Since E'Wave has beaucoup SPL capability, go for parallel.

UNLESS the woofers are wimpy on the very low end, in which case you might do the "0.5" thing and run one of them as a "Helper" to augment the bass. To do that, you'll build for 8 Ohms, but put a high-value inductor in series with the second driver, like 20 mH, #266-960. Yeah, not cheap, but.... :thmbsp:

 

[Russellc]

Russell, I think I am going to pass, as well. I have some unused 1", 1.4" and 2" drivers laying about that I need to utilize before buying yet another pair of 1" drivers.

Maybe the better idea is to sell the seleniums and buy the DE250s?

I'm a little upset with myself for not getting the 1" 18sounds while on clearance.

I missed out on that one as well. So many E'wave driver possiblities, so little time! Oh, well, one can go broke buying bargains.

Russellc

 

[Russellc]

B&C DE 250 crossover tweeks

Zilch, how's the tweeked high pass for the B&C DE 250 coming along?
at least 10 inquiring minds will want to know. I broke down for a set as well....

russellc

 

[packrat]

How does this speaker look as a candidate for an Econowave?

Pioneer A25FU20-53F:

Impedance: 8 ohms
Frequency response: 35-3,500 Hz
Magnet weight: 20 oz.
Fs: 35 Hz
SPL: 94 dB 1W/1m
Vas: 4.41 cu. ft.
Xmax: 2.4mm
Qms: 2.80
Qes: .30
Qts: .27​

I should note that I know *nothing* about building speakers other than putting the parts together so I can't tell a damn thing from the specs other than that they're fairly efficient and go from 35-3,500 Hz. I do well at following instructions but am not an original thinker when it comes to DIY.

-D

A few people here have used this woofer and liked it:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-315

and it's even cheaper than the Pioneer. Not as efficient, but it should go lower in the bass. I haven't used either - just suggesting. Good luck with it! :thmbsp:

 

[Bauhausler]

Here's a general question about woofer loading which I hope has a simple answer. How do the requirements of a sealed box change when using 2 woofers instead of 1?
Assume that a woofer requires a sealed box of 5L. Other things being equal, will 2 identical woofers require a sealed box of 10L? My instincts tell me that the answer might be 7L (5 X 1.4).
Thanks

 

[Paratima]

A few people here have used this woofer and liked it:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-315
and it's even cheaper than the Pioneer. Not as efficient, but it should go lower in the bass. I haven't used either - just suggesting. Good luck with it! :thmbsp:

The Dayton 10" Classic referenced above works for me, big time! :thmbsp:
Shown in the ZLH-17 configuraton with Selenium D210Ti's and Dayton H07 waveguides.

 

[dnewma04]

Here's a general question about woofer loading which I hope has a simple answer. How do the requirements of a sealed box change when using 2 woofers instead of 1?
Assume that a woofer requires a sealed box of 5L. Other things being equal, will 2 identical woofers require a sealed box of 10L? My instincts tell me that the answer might be 7L (5 X 1.4).
Thanks

It's best to just assume double. In reality, with typical box leakage, it's marginally smaller than double.

 

[ROSSO]

Here's a general question about woofer loading which I hope has a simple answer. How do the requirements of a sealed box change when using 2 woofers instead of 1?
Assume that a woofer requires a sealed box of 5L. Other things being equal, will 2 identical woofers require a sealed box of 10L? My instincts tell me that the answer might be 7L (5 X 1.4).
Thanks

And do you get a 3 dB LF amplitude gain by simply doubling, or does it just require twice as many watts? Wouldn't seem to be any reason for two to go lower, just louder, if there were watts available? Obviously the impedance is going to either double or drop by half, so a suitable crossover mod would likely be required. Easy to see that two could be a pitfall.

 

[ZeroJunk]

parts list specifies components for different LF driver impedances.

Since E'Wave has beaucoup SPL capability, go for parallel.

UNLESS the woofers are wimpy on the very low end, in which case you might do the "0.5" thing and run one of them as a "Helper" to augment the bass. To do that, you'll build for 8 Ohms, but put a high-value inductor in series with the second driver, like 20 mH, #226-960. Yeah, not cheap, but....

Thanks Zilch, I like that idea but can't find your part number or a 20 MH at Parts Express.

 

[tubino]

Thanks Zilch, I like that idea but can't find your part number or a 20 MH at Parts Express.

18mh 14ga toroid $65

20mh 16ga Erse $32 Part number = 266-960 (one digit off from previous link)

 

[Wayne1]

Try PE # 266-960

Erse 16awg Super Q Inductor

 

[dnewma04]

And do you get a 3 dB LF amplitude gain by simply doubling, or does it just require twice as many watts? Wouldn't seem to be any reason for two to go lower, just louder, if there were watts available? Obviously the impedance is going to either double or drop by half, so a suitable crossover mod would likely be required. Easy to see that two could be a pitfall.

With the same amount of watts, you'd gain 3dB.

So, 2 speakers getting 1w each will have 3dB more output than 1 speaker getting 2w. I always try to seperate power and drivers when determining the amount of output you should expect.

Doubling of drivers gives you 3dB.

Doubling of power gives you 3dB.

 

[ZeroJunk]

Thanks guys, got them ordered.:tresbon:

 

[Zilch]

Zilch, how's the tweeked high pass for the B&C DE 250 coming along? At least 10 inquiring minds will want to know. I broke down for a set as well....

I need some parts to get the second AR3a running, so they're moving out today, and DE-250 is moving onto the test stand.

Wouldn't seem to be any reason for two to go lower, just louder, if there were watts available? Obviously the impedance is going to either double or drop by half, so a suitable crossover mod would likely be required. Easy to see that two could be a pitfall.

At low frequencies, they will sum and more via mutual coupling to extend the VLF, BUT, they will interfere with each other above 200 Hz, generating nulls and reinforcements, messing with imaging cues. Look to the details of how multiple woofs are deployed in commercial products; it's not how prevailing assumption supposes.

Thanks guys, got them ordered.

Report your results, please. Both GordonW and Skywave-rider have used this approach successfully here. There's even a video.... :tongue:

190022/4854=39.1475​

 

[ROSSO]

With the same amount of watts, you'd gain 3dB.

So, 2 speakers getting 1w each will have 3dB more output than 1 speaker getting 2w. I always try to seperate power and drivers when determining the amount of output you should expect.

Doubling of drivers gives you 3dB.

Doubling of power gives you 3dB.

So this piques my engineering curiosity. The 3 dB gain for doubled power I understand - that's elementary physics. To get the same effect solely by doubling the number of drivers (without adding more power) would need to be the result of improved electro-mechanical efficiency? Otherwise, how do you square the gain with conservation of energy? :scratch2:

 

[Russellc]

So this piques my engineering curiosity. The 3 dB gain for doubled power I understand - that's elementary physics. To get the same effect solely by doubling the number of drivers (without adding more power) would need to be the result of improved electro-mechanical efficiency? Otherwise, how do you square the gain with conservation of energy? :scratch2:

Yes. You have two drivers, so they only have to move 1/2 as much to move the same amount of air.

Russellc

 

[Steve O]

So this piques my engineering curiosity. The 3 dB gain for doubled power I understand - that's elementary physics. To get the same effect solely by doubling the number of drivers (without adding more power) would need to be the result of improved electro-mechanical efficiency? Otherwise, how do you square the gain with conservation of energy? :scratch2:

I have exactly the same question...power is power regardless of the number of speakers it's divided amongst...at least to a first approximation. The concept works if speakers are parallelled and voltage remains constant as it might with a zero impedance source but input power is doubled in this case. Regardless, that's not what Polycarbonate David stated. :scratch2:x2

 

[Russellc]

I have exactly the same question...power is power regardless of the number of speakers it's divided amongst...at least to a first approximation. The concept works if speakers are parallelled and voltage remains constant as it might with a zero impedance source but input power is doubled in this case. Regardless, that's not what Polycarbonate David stated. :scratch2:x2

For a given speaker that is a given size and sensitivity, using two will decrease by 1/2 the power require to get to the same sensitivity. The same power ( not half) will cause two cones to produce 3 db more sensitivity.

This is precisely one of the design features of a D'appilito alignment. Use a dome tweeter that is 93 db efficient ( for example) two woofers that are ( in example) 89 db. The 2 woofers together gain 3 db, making them 92 db efficient. Now you need to trim 1 db or so in this example for them to match in sensitivity.

Hope this helps

Russellc

 

[Zilch]

At very low frequencies, mutual coupling gives us an additional 3 dB; the pistons behave as one.... :yes:

 

[Steve O]

For a given speaker that is a given size and sensitivity, using two will decrease by 1/2 the power require to get to the same sensitivity. The same power ( not half) will cause two cones to produce 3 db more sensitivity.

This is precisely one of the design features of a D'appilito alignment. Use a dome tweeter that is 93 db efficient ( for example) two woofers that are ( in example) 89 db. The 2 woofers together gain 3 db, making them 92 db efficient. Now you need to trim 1 db or so in this example for them to match in sensitivity.

Hope this helps

Russellc

But in most DA designs aren't the LF drivers in parallel? If so, each has the same voltage across it so power input to the LF section is doubled, thus the +3dB increase in (assumed) voltage sensitivity cited.

Thought experiment: Assume I have a speaker that produces 90dB with one watt of input under some set of specified conditions. By what's been offered so far, every doubling of the number of speakers results in +3dB increase in level (not sure if were talking sound power level or sound pressure level here). Now assume I have 1024 identical speakers each capable alone of 90 dB. 1024 is 10 doublings so now I have a system capable of 120dB @1W or taking it the other way 90dB @1mW. This doesn't seem reasonable. Taken to an admittedly absurd limit, an infinite number of speaker would be capable of 90dB with zero power input. What am I missing here?