silk purse from sows ear contest?

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KaffiMann

KaffiMann

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So to sum it up:
30$ or 37€ pick your shop either USA or Europe for XO parts and drivers only, shipping/tax/import/etc does not count towards the sum.

Bonus points for:
1. Good frequency response
2. Using regular priced components/no buyout or sale
3. Money left over
4. Photos of diyaudio members dumpster diving/Scavenging

So basically a free-for-all, but extra points awarded for getting certain boxes ticked.

Is this something people can live with? :)
 
KaffiMann

KaffiMann

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Dumpster diving/scavenging/recycling for everything else would be my choice if I get to decide.

The 30$/37€ sum is for drivers and xo parts only.

Depends if people agree to it though, so we can get going. :)

But I bet Pano has a head start already :D

I would like to add SPL/w as one major point increaser thingy if that's ok:
1. Good frequency response
2. Good sensitivity/SPL/w
3. Using regular priced components/no buyout or sale
4. Money left over
5. Photos of diyaudio members dumpster diving/Scavenging
 
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J

Jared

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Joined 2002
DonVK said:
Does the $30 exclude the enclosure material ?
Click to expand...

yes, enclosure wood / metal / esoteric unobtanium etc., port PVC or formed MDF or whatever, paint, glue, wire, screws are all free.

ONLY the drivers and signal path pieces count with exception of amplifiers and source.

@TMM - I like your idea and will participate in that as a contest, but I think enough people have expressed interest in open ended driver selection that this contest should stay that way. Do you want to make another thread for a same drivers contest? I can do so if you prefer, but it is your idea, you should get to own it?
 
DonVK

DonVK

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I could do that.

The $30 standard price is low, but still possible, as long as the enclosure material cost is excluded. Bonus points for recycling or re-purposing material. Then the speaker could return to where it come from :)
 
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P

phivates

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Joined 2011
That would be my question also. Otherwise we need to keep to the OP's challenge on this one, which includes having a good time with it, and get deadly serious in some other contest. Dumpster diving for materials would seem indicated though not everyone has access to construction sites.
 
KaffiMann

KaffiMann

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Yes, sort of, bonus for recycling if you strike whatever pose and post the photo of doing just that. :)

Material is not a problem, maybe someone throws away some furniture that's broken but the drawers are fine, cabinet doors, etc. Just recycle whatever is close.

No recycling photo, no bonus, so it should not be an absolute.
 
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Pano

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$30 is quite low, but that's part of the challenge. If we aren't allowed to use buy-outs or salvage, that disqualifies a lot of drivers I have, but oh well. :)
I don't think putting a penalty on low efficiency is useful for a project with such a low price point. Most should end up the low to mid 80dB/2.83V range anyway, given the limitations.

And yes, I have a good head start. :D
 
KaffiMann

KaffiMann

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Pano:
If everyone agrees to the last iteration of rules, then you can use buyouts and obsoletes, but you will not get the extra bonus points. One box less for you to tick off in the bonus department.

The point of adding SPL/W was that if you get lots of buyouts for cheap, then you lose the "no buyouts" bonus, but you can get more score on the SPL/W box.
Diversity!

Everyone wins. :)

Edit:
Also please note that "Pretty" does not count.
Just so I can stand a chance :p
 
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J

Jared

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Joined 2002
TMM said:
Basically impossible to accomplish unless everyone measures outside in a big open space (not everyone has access to one) or constructs a room with identical dimensions (not financially practical).

I think if we are running a 'competition' it would be better to standardise the drivers, the dimensions of the baffle and the placement of the drivers on said baffle.
The competition is then to design the crossover. This would be far more fun IMHO as everyone can try each others crossover designs, measure, listen and decide for themselves. People can flaunt their own measurements if they so wish, and people who prefer to design without relying so heavily on measurements, or don't own measurement equipment, can still participate too.

It's probably best to pick some drivers available in the US since most people are in the US and most US distributors ship overseas. If you live overseas like I do then you get hit with the exchange rate and shipping but that's too bad. At least everyone is still on an even playing field as far as the quality of drivers used.

Might I suggest:
Dayton Audio DA175-8 7" Aluminum Cone Woofer
Peerless by Tymphany BC25TG15-04 1" Silk Dome Tweeter

These are known good performing drivers, so anyone can be happy that we are making speakers which can actually sound good, not just trying to make $20 of garbage sound barely listenable. They are drivers that should hopefully be around for some time yet, so DIY'ers can benefit from the designs for years to come. The DA175 also presents some crossover design challenges, so would make for an interesting 'competition'.

If we still want to keep it really cheap then perhaps:
Peerless by Tymphany 830656 5-1/4" Paper Cone SDS Woofer
dunno about tweeter, maybe this?
GRS 1TD1-8 1" Dome Tweeter 8 Ohm
Click to expand...


How about instead of the GRS tweeter, the dayton I posted earlier:
Dayton Audio TD20F-4 3/4" Soft Dome Neodymium Tweeter 4 Ohm
Looks like with two of those peerless 5-1/4" would pair nicely, would be a 4 ohm speaker...
 
S

ScottG

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Joined 2003
Pano said:
$30 is quite low, but that's part of the challenge..
Click to expand...

I think the amount is to low, and the parameters to wide.

I'd prefer to see something like:

1. No "fullrange" *single* driver only, must use at least *two* drivers though they can be the same (and can be "fullrange" drivers). Must not use more than 4 drivers.
2. Specified *minimum* expected bandwidth (-3db at what frequency both at low freq. and high freq., with builder specified reference listening axis).
3. Specified *minimum* spl before exceeding a specified THD and a higher-order (4th,5th, etc) threashold.
4. Specified maximum baffle width.
5. Maximum dollar amount for drivers with a reasonable given value if they are "on-hand"/re-purposed drivers/gifted drivers.
6. Maximum dollar amount for any single driver.
7. Reasonable adjustments for builder location with costs. (..customs/VAT/shipping.)


If you don't do something like this I could "whip-out" my Parts-Express 69 cent fullrange drivers. Put it on an infinite baffle, and win with little bass extension and poor spl capability. :eek:
 
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wolf_teeth

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That's kind of how I feel too, Scott.

For me:
-Price is too low. $100/pair for drivers and xover is actually pretty hard to do *well* with retail costs, and would be my preferred limit- especially if HD, SPL, and bandwidth become priorities.
-2-way assembly mandatory.
-maximum cabinet volume stated.
-No buyouts or NLA, for use in making it buildable.

Later,
Wolf
 
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