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woodbe
22nd August 2006, 11:01 PM
Do I get a prize for the first post in the HiFi forum?

I haven't spent much time on this since I got interested in woodwork, but I'm going to get back into it, perhaps with a hybrid Audio/Woodwork project.

http://www.adam.com.au/maf/AudioProjects/

woodbe.

veggiepatch
22nd August 2006, 11:56 PM
Welcome Woodbe (clever nick!)

Having made my first pair of speaker cabinets (?) as a 12 year old almost 35 years ago, I have much interest in this facet of woodworking. With increasing demand for sound quality and quantity, speaker enclosure building is a very exact science. In saying that, I have only made one more set of speakers and that was in the late 80s.

There is quite a lot of quality info available on the net regarding speaker building but it can be very technical with regards to fine tuning the enclosure to the drivers and crossovers involved. Some websites supply a downloadable speaker enclosure calculator, working out speaker and port dimensions after entering in the electrical/electronic and dimensional parameters of the drivers intended for use. In NSW, I use Jaycar Electronics for bits and pieces as well as advice for any electronic related projects.

In summary, erring on the side of safety is recommended, that is, design a speaker system capable of handling 200 watts rms per channel for an amp that's rated at 100 watts rms per channel for example.

Hope this info is of some help to someone and if any further info is required, feel free to give me a yell (make it a loud one....the amp's pumping!)

veggiepatch

woodbe
23rd August 2006, 10:25 AM
Hi vegiepatch :).

Yes, there is a wealth of information out there if you are prepared to look. Some people's work and ideas stand out, check this excellent site out:

http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm

I wouldn't mind building one of his designs...

Be careful specifying high power speakers on a low power amp. If the speakers are low efficiency, the low power amp could be driven to clipping at relatively modest volumes. Clipping is nasty to speakers. I'd actually go the other way around, run a high power amp into lower power speakers - generally the higher power amps will run them just fine, and without clipping even at high volumes.

woodbe.

dalejw
23rd August 2006, 10:48 AM
In summary, erring on the side of safety is recommended, that is, design a speaker system capable of handling 200 watts rms per channel for an amp that's rated at 100 watts rms per channel for example.



Believe it or not, it's actually the other way round. One of the easiest ways to kill speakers is by over driving your amp into "clipping" that is when an amp is driven up past it's capacity so the tops of sine waves in the AC voltage supplied to the speakers are clipped so the speakers are recieving direct DC voltage. This burns out speaker voice coils really quickly and can be a bit tricky to hear.

Conversely a larger amp will have the speaker cones reaching full excursion (overdriving speakers) before the amp is driven into clipping. This effect is a lot more noticeable than the clipping effect as it makes a horrible popping sound.

A bigger amp than your speakers will allow you to get the most out of your speakers. This has obvioulsy got to have some common sense applied to it as you'll probably only get one shot a turning down a 200w amp that's flat out and connected to your 5w transistor speaker :D

dalejw
23rd August 2006, 11:13 AM
Ooops double post above. Joys of leaving the computer to make brekkie before posting.

Moved rest of post to new thread so as to not take over :) .

Iain
23rd August 2006, 11:31 AM
Integrated anti theft mechanism... They weigh about 80kg each.
Time for one upmanship:D We built a couple of 14cf enclosures several years ago to house Tannoy studio monitors, built from 5" reinforced concrete and a forklift was used to put them in the new house being built.
God help anyone trying to steal them.
The amp was a home brew running 200w rms (2kh sine continuous) per channel and it was sweet as.
Still in the house (not mine) and has had a few amp changes along the way.

woodbe
23rd August 2006, 12:01 PM
Joys of leaving the computer to make brekkie before posting.


Ok, you win. No way I can get my Computer to make brekkie :D

woodbe.

dalejw
23rd August 2006, 09:22 PM
Ok, you win. No way I can get my Computer to make brekkie :D

woodbe.

:D

soundman
18th September 2006, 10:50 AM
Ahhhh the things we did in the heddy days of HIFI. Brick speaker enclosures:rolleyes: , folded horns the size of next doors garrage:eek: , amplifiers built from welders:confused: , of course speakers bigger than an upmarket fridge:D and all sorts of other foolishness.

But was it all worth it...... we thaught so at the time.
If you want a chuckle have a look at some early HiFi books:D

There is no way that SWMBO would allow any of that sort of stuff these days.
Of course there was a lot of BS about stuff and an awfull lot of "mines bigger than yours".

That MF dosn't look too bad I've cleaned up worse fire scenes that that more than once.

Just consider though that much of the stuff we thaught was just:) :D :eek: marvelous 20 years ago sounds like a bag of S#$% now, only a very small amount of the old stuff has aged well.

I've fired up some old gear in the recent past......:( is this broken..... nope it always sounded like that.
Don't get me wrong I like old gear and believe me I have my fair share, but even the better sort of cheaper stuff sounds good these days & I think we often take that for granted.

Just check out the diference in quality between that " cheapo kit set;) " being constructed compared to that "top of the range, state of the art HIFI icon, Musical Fidelity" item and all becomes obvious.:confused:
cheers