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-   -   looking to build a high efficency, small speaker. (http://www.diyaudio.com/forums/multi-way/69812-looking-build-high-efficency-small-speaker.html)

demogorgon 15th December 2005 07:15 PM

looking to build a high efficency, small speaker.
 
High all!

this will be my first loudspeaker project not being buildt from plans made by others, so i'm quite unexperienced in aucustics and other aspects conserning speakers, and so i would appreciate any help given!

What i'm out to build is a pair of highly efficient small speakers to mate with a small battery driven legacy gainclone for when i'm on trips or as backup when everything else i have is in pieces awaiting "improvements" ;)
as this is the use, low end extension is not expected, i'm not looking for any lower that 100HZ, perhaps even higher, 120, 130 if it has to go as high, when possible, theese speakers will be mated with a sub or two. not on trips and such offcource.

the small\efficient part of this is offcource a paradox, as size = efficency in regular speaker construction, but non the less, i hope to be able to pull this off. some thoughts on the project as far is glassfiber box material, about 90bd\1w efficency rating (hopefully), and relativly light weight. I belive i will have to restrict myself to 5' drivers max.

the first thing i'l have to do is sum up compatible drivers, if any.
and so i would ask your help.
i have limited funding as i' a student on a budgette, but everything has it's cost, and you get what you pay for, so i'l put a pricelimit on this project of 250 bucks, not counting the enclosure.

If drivers are found, and they can be transported here up north, this thread will become a construction journal, and a sumary will be written together with the plans and how-to, and posted on my website, if non other with more prominent and renowned websites find the project worthy.

comments and advice is welcome, know-how and explenations even more. :)

I hope this will grow into a good projectthread!

thanks
Marius

demogorgon 15th December 2005 07:30 PM

First uppdate:
the first candidates has been located:
goldwood gw-205/4s
dayton dc130as-8
audax am130z2
aurum cantus ac-130f1
I'm leaning towards this aurum cantus ac-130mk2
but this one to looks good :)
davis 13klv5na
this one to:
davis 13klv5a

the tweeters i'm looing to use:
vifa d27tg-35
vifa d27tg-35]Hi-Vi sd1.1-A[/URL]

so what do you guys think?

joe carrow 15th December 2005 08:59 PM

How high?
 
Hi, glad to hear you have a well defined project in mind!

Unfortunately, I can't call ~90db an "efficient" speaker. If I were you, I'd consider a horn tweeter and a pro driver. It would be quite possible to get two 6" PA drivers and a horn into an MTM arrangement with a horn for a net sensitivity over 94, maybe as high as 96 db at one watt.

Midbass driver- http://www.partsexpress.com/pe/showd...number=295-015
Easily get you down to 100 hz ported, just shy of 93 db/w/m, and $15 each.

And this tweeter-
http://www.partsexpress.com/pe/showd...number=290-534
for under $40.

Call it a 3 or 4 khz crossover with some padding on the tweeter, and at $70 in drivers per side, you have $55 per side for crossover components.

Resonably small, wickedly loud, and almost twice as efficient as your initial drivers. Sorry if 6" is too large, but size and efficiency really are hard to have together.

Good luck!

Joe

zobsky 15th December 2005 09:11 PM

Re: How high?
 
Quote:

Originally posted by joe carrow
Hi, glad to hear you have a well defined project in mind!

Unfortunately, I can't call ~90db an "efficient" speaker. If I were you, I'd consider a horn tweeter and a pro driver. It would be quite possible to get two 6" PA drivers and a horn into an MTM arrangement with a horn for a net sensitivity over 94, maybe as high as 96 db at one watt.

Joe


consider bipole (T, M,M) if you want to reduce the frontal "faceprint" and gain some dB efficiency at the same time.

not bad sounding either, .. and reduce the need for baffle step compensation

con: need an extra pair of midbass/ midrange drivers.

eVITAERC 15th December 2005 09:15 PM

Have you looked into the various full-range options? Sounds like the Fostex varieties are right up your alley.

demogorgon 16th December 2005 04:31 PM

Re: Re: How high?
 
Quote:

Originally posted by joe carrow
Hi, glad to hear you have a well defined project in mind!

Unfortunately, I can't call ~90db an "efficient" speaker. If I were you, I'd consider a horn tweeter and a pro driver. It would be quite possible to get two 6" PA drivers and a horn into an MTM arrangement with a horn for a net sensitivity over 94, maybe as high as 96 db at one watt.

Midbass driver- http://www.partsexpress.com/pe/showd...number=295-015
Easily get you down to 100 hz ported, just shy of 93 db/w/m, and $15 each.

And this tweeter-
http://www.partsexpress.com/pe/showd...number=290-534
for under $40.

Call it a 3 or 4 khz crossover with some padding on the tweeter, and at $70 in drivers per side, you have $55 per side for crossover components.

Resonably small, wickedly loud, and almost twice as efficient as your initial drivers. Sorry if 6" is too large, but size and efficiency really are hard to have together.

Good luck!

Joe

Hi joe!

The poblem is size offcource, i dont have enough room to play with, and the drivers you pointed to have some problems i dont see a answer to, especially the freq. respons on the dayton is unbearable, as well as the severly limited xmax. i would belive this will make distortion skyrocket?
I have heard horns done right sounds pretty damn good, just to bad i'v never heard one done right. the high crosover to is a obstacle i cant overcome. i know vifa has a mildly hornloaded dome tweet thats supposedly quite good, i'm gonne look into that. scores a good 96bd\1w too.

as you say, size and efficency is two that dont mix easily, thats why i dont aim any higher than ~90db\1w while demanding a certain level og sound quality.


Quote:

Originally posted by zobsky



consider bipole (T, M,M) if you want to reduce the frontal "faceprint" and gain some dB efficiency at the same time.

not bad sounding either, .. and reduce the need for baffle step compensation

con: need an extra pair of midbass/ midrange drivers.

Hi Zobsky.

I have considerd this, though only if i find suitable 3' or 4' drivers.
why does this reduce baffel step?

Say hi to Haggard(?) for me.
or Hårek as his name is here.

Quote:

Originally posted by eVITAERC
Have you looked into the various full-range options? Sounds like the Fostex varieties are right up your alley.
I'm going to skimm through parts express to see if i find something suitable, though the problem with fullrangers usally is, if they'r linear, they cant take power, if they can take power, they'r not linear. at least thats the impression i'v gotten as far.

The hi-Vi 3'inchers i keep hearing about have been on my list, but dropped, the efficency was way to low, even if i used 3 of them, on i dont really have room for any more.


thanks for your replys guys!
appreciated! and remember to keep em' comming.

-Marius

demogorgon 16th December 2005 04:50 PM

Hi again

been skimming through the different options of fullrange speakers over at partsexpress, and come up with the following candidates:
4' tang band bamboo driver
TANG BAND W3-871S

the bamboo driver looks almost to good to be true, any thoughts on problems with this driver i cant identify?

it's reasonably smooth while having a bit of xmax and efficency, i'l be topping 93db\1w with 3 of theese..
could someone let me know the vas in liters?

thanks
Marius

bogoes 16th December 2005 06:27 PM

The TB Bamboo is suppossed to be a nice driver, someone of the PE TechTalk Board did a project with one but for the life of me I can't remember who it was. I can personally attest to the quality of the W3-871S. As far as your project goes, I would look to the possibility of doing a micro MTM with the TB Bamboo and a small flanged tweeter like the Dayton Neo. This tweeter weighs in at 93dB sensitivity and can be crossed from 3.5kHz on up very easily. Since the tweeter is only about an inch across you can have very close CTC spacing on the TBs (about 5 - 6") which will dictate you highest xover point (don't have the calculation for that right now) and the 2 TBs in parallel would yield a 95dB sensitivity which without any padding on the tweeter would give you about 2dB of built in BSC. You might want to add a little bit more BSC but you'll still be at about 91dB overall in a very small package. Plus with the TBs rolled off at an appropriate point and a single tweeter handling the highs, you won't have to worry about the lobing you would get with 3 TBs running full range. My only concern would be whether the gainclone could handle the lowest impedance point which would probably be around 3.6 ohms.

My initial thought was definately that of eVITAERC. A Fostex FE106E (available from Madisound) or the like would make a high sensitivity and very easy to drive load in a small package. And while maybe not the best thing in sound quality, they would certainly do the trick on the road and I wouldn't worry too much about xmax since your power is coming from a battery powered gainclone. Ask around the Fullrange forum to get a feel for the options on that side.

Also, for the record the VAS of the TB Bamboo is 6L. You can Google this, just use the phrase .21 cu ft to liters and out pops your answer, very handy.

Good luck and let us know what route you take.

demogorgon 16th December 2005 08:23 PM

Chris! thanks for your reply!

the more i think this over, the more i lean towards the aurum cantus 5' in a small bassreflex with a seas or vifa tweeter crossed at 2.5khz with a 2 order filter, and a small notch for the respons peak at 1.4khz.

but at the same time, a duble\triple TB W4-1320SB is looking good as well, as i'l get away without a crossover and the usage of multiple drivers guarantee lower distortion that simply using one.
i cant afford a mtm with the aurum, considering both the monetary costs as well as the cost in ocupied lugadge room. I could with the TB bamboo, but what will be gained in contrast to a simple 2\3 driver paralell coupling? you reffer to lobing?

as for power, these speakers will be driven by whatevers at hand, but need to be compatible with a low power source, low impedans is not a problem i would think, taking ohms law into account, not a lot off voltage will be applied here i anycase (why i need relativly good efficency), so there's curent to spare, even with a lm1875.
should i be wrong however, blowing up an amp is to me not much more than an excuse to build a new one (unless it's expencive offcource) ;)

You altso refer to BSC, could you please clarify?

Thanks
Marius

Rademakers 16th December 2005 09:21 PM

If you need it really efficient ;)

Mvg Johan


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