S.p.q.r. Os-1

[Harderror]

Had a little more time recently and decided to mess around with Transmission-Line geometry. Really fun stuff! So, I am submitting these preliminary drawings and sim graphs for my first OPEN SOURCE (OS-1) speaker. This design is for the FE127

I am going to release it under what has become the standard for public not for profit creative licensing, the GNU licensing structure. Therefore, anyone who wants to work on the design can as long as it isn't for profit. Just like the Frugal projects. I thought it would be fun to go with what this hobby is all about. Innovation through experimentation within the community and an exchange of free ideas and thoughts.

As it sits now, it is a 1/10 ratio Transmission line enclosure designed for flat response, compact size, easy build, and good looks. A sub-woofer will be needed for the lowest registers (as is expected in an enclosure of this size) but imaging should be good. A BSC circuit with a 6-6.5 ohm resistor and a 3mh inductor should do the trick. That's a 6 db attenuation centered at 350 Hz.

Oh, and Martin, excuse if I am not up to date with my dues again. Just let me know and I will get the cash over to you. Thanks!

So, what am I getting at? Is it worth putting the plans up for a build? Yes, I am trolling for interest.

[Harderror]

Sorry for the double post but I wanted to add a picture with a view of the inside and dimensions of the out to help you better understand the compact size and easy construction.

[GM]

Well, you're ~60 yrs late to this particular 'party and I've been periodically promoting high aspect ratio TQWTs ever since I got on-line and now with the interest in tapped pipe horns adding more loading in (sub) woofer apps, me and especially Bgorno have been promoting high aspect ratio T-TQWTs, so you got my vote for the concept if not the fancy woodworking since historically I've always been in a time 'crunch'.

You have a history of reading too much into my observations, so I'll add that all I'm suggesting is that you may want to offer both a technically most correct and/or stylized design and a 'no frills' one for the time and/or woodworking challenged among us.

FWIW, I've sometimes had to add a duct vent to the terminus to get the best in-room blend, so factoring in that large vents should be floor loaded since they have the widest BW and more easily critically damped externally with minimal fundamental output losses, you may want to consider a down-firing terminus option also.

GM

[Scottmoose]

Good calls. Certainly has promise.

[rjbond3rd]

Originally Posted by Harderror

I am going to release it under what has become the standard for public not for profit creative licensing, the GNU licensing structure. Therefore, anyone who wants to work on the design can as long as it isn't for profit. Just like the Frugal projects.

By GNU I'm guessing you mean the GPL, but the GPL does not prohibit commercial exploitation. It only says that if you redistribute, you can place no distribution restrictions on the recipients (and you must provide the source code).

I think you may mean the Creative Commons licenses, which can prohibit commercial use.

Cool-looking design. GM suggested something functionally similar (aesthetically different) to VanJerry for the AN 12 I think.

[Harderror]

Originally Posted by rjbond3rd

By GNU I'm guessing you mean the GPL, but the GPL does not prohibit commercial exploitation. It only says that if you redistribute, you can place no distribution restrictions on the recipients (and you must provide the source code).

I think you may mean the Creative Commons licenses, which can prohibit commercial use.

Cool-looking design. GM suggested something functionally similar (aesthetically different) to VanJerry for the AN 12 I think.

Thanks for that tidbit. Yes, the Creative Commons. I went and reread and saw what you meant.

[Harderror]

Originally Posted by GM

Well, you're ~60 yrs late to this particular 'party and I've been periodically promoting high aspect ratio TQWTs ever since I got on-line and now with the interest in tapped pipe horns adding more loading in (sub) woofer apps, me and especially Bgorno have been promoting high aspect ratio T-TQWTs, so you got my vote for the concept if not the fancy woodworking since historically I've always been in a time 'crunch'.

You have a history of reading too much into my observations, so I'll add that all I'm suggesting is that you may want to offer both a technically most correct and/or stylized design and a 'no frills' one for the time and/or woodworking challenged among us.

FWIW, I've sometimes had to add a duct vent to the terminus to get the best in-room blend, so factoring in that large vents should be floor loaded since they have the widest BW and more easily critically damped externally with minimal fundamental output losses, you may want to consider a down-firing terminus option also.

GM

Thanks for the response. I see what you are saying about the complexity of the build. It is simple except in those miter joints! I will take your advice and go ahead and put out two sets of plans. It is a simple matter to do so. As for the floor loading, I will do that as well. I can see where it would be difficult to tune the vent in the current front firing configuration. Besides, I don't think there would be any loss of clarity from firing down instead of forward. I will try to get one built this weekend to see whether it has potential in its current configuration.

[Harderror]

I managed to finish a pair of the OS-1's over the weekend. I must say, they are quite good. Even better than I thought they would be! This is a new record for me, from conception to built in 5 days! Hehe.

Ok, some thoughts on the build. The miters are not hard if you understand angles and have the equipment to cut them. I made no mistakes on them. I made mistakes laying out the shape of the side the first time though. Once I had it right, I made notes and used the first as a template for the rest. It went together surprisingly smooth. As GM said, it is not the simplest of builds. to get it really right without going crazy a 12 inch miter saw is a MUST.

Sound comments. Ok, I didn't finish getting them together until this morning so I only have some listening today to go on at this point. That said, they sound pretty fantastic. In fact, this is the first time I have heard the 127 really used to its potential. Bass is solid. I am getting an easy 50 Hz and the 40s are there if not super strong. I am using a parametric EQ to calculate my BSC circuit and at this I would say 4-5 db of attenuation is about right. 6 as I originally stated may be a bit overboard. We will see though, as it is a new build, I am not sure of the bsc numbers. I will keep this thread posted.

So far, this is everything I could have hoped for. Now we just need some others building and inputting what they think! I would really like to see this loudspeaker become something special.

i will do my best to get the plans out soon. I WILL put out a simple plan and a sexy plan. And let me say, the design is quite sexy. My wife can't stop commenting on the looks of them. Any input is always appreciated!

Attached are some photos of the build. Oh, and the color is just white primer for now.

Tom

[edjosh23]

Those look great!

I like the rock band setup too, hopefully plays through the speakers!
Is that a dimple in the dustcap on your right speaker?

Josh

[Harderror]

Originally Posted by edjosh23

Those look great!

I like the rock band setup too, hopefully plays through the speakers!
Is that a dimple in the dustcap on your right speaker?

Josh

Good eyes, good eyes! Hehe, yeah, my cats were messing around one day and one found its head in the driver. Man, I was livid. Not really noticeable as far as affecting the sound goes though so I just deal. I don't want to have to buy a new one ya know? Oh yeah, the rock band plays through them quite well! My office system is the more audiophile grade system, this one (the livingroom) is not bad but has to serve many purposes so...

Tom