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DIY audio: what are you building?


Paul Spencer

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Earlier this year I built a set of DIY red speakers using left over drivers. They sound brightish and they do image well but would like to drop the tweeter about 3db. The boxes were tuned by ear so that the bass would be strongest in the 50 to 150hz range. In order to tune the boxes I used cardboard cut outs and then once happy with the final tuning got the ports cut to the correct length. Paint is 9 coats of single stage acrylic enamel wet sanded between every 3, 2, and 2 coats.

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10 hours ago, mwhouston said:

Can anyone help me find a 12" woofer with a Fo of 25hZ and effcienecy of 96 or better db. I'd like it to work in a 60ltr sealed or ported box.

 

links will help.

 

I doubt if you'll find a 12" driver at that efficiency at any where near that FS. Thats pro-sound efficiency and with an FS somewhere at around 60hz if your lucky.

I think the Visaton TIW 300 would be a good choice for its lowish FS, decent efficiency and low qts allowing for a smaller enclosure. Would work in a 60L vented enclosure, or close to it.

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I am starting in 2 projects that I hope to have them done by xmas 2018. I will be building a biamp setup for 4 channels.

First is to bridge 2 B&O amp modules for each speaker . I will run balanced to each amp, and each amp will go to its own speaker. Both of the amp modules will be going into one custom amp case that will sit on top of each bass bin.

Second project is to build 4 Klipsch Belle bass bins for my horns.

I will most likely use a Minidsp ddrc88m for my crossovers, and Dirac.

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I now have some foam cut for my Miniwaves:
http://redspade-audio.blogspot.com/2011/03/miniwaves-foam-mod.html
foam-waveguides.jpg&key=b8d17fbefa95caea4e2693761d17aa6b6f41af6e922d7ce294b22483f85c7957
Not sure if I posted in here, but Roger's Econowave improved dramatically with the foam in smoothness. The foam gets these things matching domes in smoothness.
I am a little confused.. What is the black parts for, and how did you get them cut to the shape? How is this used to make the other parts?
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11 hours ago, georgepapa said:

I doubt if you'll find a 12" driver at that efficiency at any where near that FS. Thats pro-sound efficiency and with an FS somewhere at around 60hz if your lucky.

I think the Visaton TIW 300 would be a good choice for its lowish FS, decent efficiency and low qts allowing for a smaller enclosure. Would work in a 60L vented enclosure, or close to it.

My current jaycar poly cones do 30hZ  easy in a 60ltr sealed box. But only 92db. 

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A lot of car stereo subs have low fs but generally aren't over 88-90db sensitivity. What they are though is cheap which would allow for two or even three subs versus one from the madisound link! Designed for small cab usage you could do a dual opposed setup for quids....

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2 minutes ago, bjc said:

A lot of car stereo subs have low fs but generally aren't over 88-90db sensitivity. What they are though is cheap which would allow for two or even three subs versus one from the madisound link! Designed for small cab usage you could do a dual opposed setup for quids....

To change what I have, which is 92db effecient 12" woofer in a sealed 60ltr box which goes to 30hZ, I must have a huge jump in afficiency and bass down to 30hZ.

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Why? Why 30hz and why 92db efficiency? Are you using very low amp power? Build a large ported box if need be but in a sealed box your sub will play below 30hz unless you're trying to reach a certain output level in room and pushing it past its limits?
In any case it's easier to add more subs, go a large ported/TH box or buy a larger sub... Any sub will play below its fs, how loud you want it to be before max excursion is up to you but as I said it's easier to add more subs, go large ported or larger subs instead of trying to find a low fs high sensitivity subwoofer. EQ is your friend also....
That's my take on it anyway!

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1 hour ago, bjc said:

Why? Why 30hz and why 92db efficiency? Are you using very low amp power? Build a large ported box if need be but in a sealed box your sub will play below 30hz unless you're trying to reach a certain output level in room and pushing it past its limits?
In any case it's easier to add more subs, go a large ported/TH box or buy a larger sub... Any sub will play below its fs, how loud you want it to be before max excursion is up to you but as I said it's easier to add more subs, go large ported or larger subs instead of trying to find a low fs high sensitivity subwoofer. EQ is your friend also....
That's my take on it anyway!

At the mo using a pair one of my DIY 150W Class D monoblocks so not low power. But also have 5W DIY tubers and a 1/3W tuber which require very high effcienecy speakers. Which I also have with my DIY Beyma 15" concentrics at 98db effcienent. The bass extension on what I'm using is excellent and I would hate to lose that. The Beyams go to 40hz with SS amps. But I can't keep both. No room. 

 

This is my current setup. Box coming for the horns.

 

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I posted a few months back my entry into Altec horns with an Italian poly compression driver. From day one I was using a L pad made with a couple of 1W carbon resistors for a db drop to the 109db efficient horns of 21db. I had it left over from the Beymas which also have a very high efficiency tweeter. I thought it well balanced and smooth sounding, no shrill notes which I have heard from other horns. The Altec sit on a 12" woofer in a 60ltr sealed box, goes down to 30Hz and crossed at 1100hz.

 

An SNA member came around for a listen and felt the horns weren't dominant enough so I brought them up 2db. Once he left I lasted about 30mins then dropped them back. They just sounded too bright.

 

I recently made another L pad with 5W wire wound resistors for a 20db drop to go part way between what my friend felt was good and what I was use to. I listen with this setup for three days then went back to the original carbon resistor L pad. The horns sounded a little shrill and though there is only 1db between the two I just didn't like it. They system had lost its smooth sounding mids and highs.

 

It then dawned on me it is not the difference of 1db that I'm hearing it is the difference in carbon resistors verses wire wound. Over the last few years all my amps, preamps, MM stages etc all have 1W carbon film resistors which I fell produces a smooth sounding warm musical drive. Ditto for the horns. I now may try a 20db pad made with carbon film resistors and see if the 1db lift will sound as smooth and warm as the -21db carbon pad but with a touch more mids and treble. 

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  • 2 weeks later...
19 minutes ago, CamSemp said:

My Kairos 3-way project is starting to take shape. Got the woofers up and running last night.

 

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Good start. Have you thought of an overall colour or going for a black finish. The woofers could stain nicely, something deep and dark. 

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MoOde 4.3 has a new build. This can be done on the player with no loss of settings. About a ten minute job. If you are on MoOde 4.2 download the 4.3 image set it up on your player then do the build update. 

 

I haven't checked but but there maybe a later 4.3 image with the updated build already. Not sure. 

Edited by mwhouston
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1 hour ago, mwhouston said:

Good start. Have you thought of an overall colour or going for a black finish. The woofers could stain nicely, something deep and dark. 

Yeah the ply on the front of the woofers has a fairly nice face. However I've decided to make things hard for myself and I've got a roll of Silver Wattle veneer to apply to the whole lot. That said, I haven't actually done a cut diagram to see if I've got enough from one sheet to do it all. May do the baffles in black or something.

 

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Edited by CamSemp
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Yet another external PS for yet another Psvane 6SN7-SE globe tube preamp. A 24VAC wall wart is use to power the PS which delivers 200V HT and 12VDC for the preamp yet to be built. The HT is choke filtered with 400uf of filtering. 

 

No humans were maimed, stunned or killed during construction. 

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