# Lets see so photos of your open baffle speakers you've built



## mjcmt (Aug 30, 2010)

Fellow Shacksters,

I've built 4 sets of speakers over the years, and now I'm interested in an open baffle speaker design. But I've never even hear a set, so I don't know what to expect either. May I see photos of the ones you built and information on choosing drivers, x-over etc. Can you describe to sound they produce and about room placement for this type of speaker.

I'm interested in something similar to this one by Jamo...well maybe not this high-end.
http://www.jamo.com/na-en/products/r-909-description/


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## viccmw (Dec 15, 2010)

Hi,

Have you come across the Orion? More information at this site www.linkwitzlab.com. As it also comes as a DIY, it might be something you are interested in.

From what is stated at this site - the Orion is placed several feet (>3') into the room for best placement. 

Rgds


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## mjcmt (Aug 30, 2010)

viccmw said:


> Hi,
> 
> Have you come across the Orion? More information at this site www.linkwitzlab.com. As it also comes as a DIY, it might be something you are interested in.
> 
> ...


It does look nice w/ the SEAS Excel drivers. I like the sound of those drivers and that is what I used on my built-up Paragon Radiant boxes in my system. But I may want to try another brand for a change in sound, but the Orion look pretty nice.
http://www.hometheatershack.com/forums/home-theater-room-photos/37734-recycled-2-ch-movies-now.html


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## Anthony (Oct 5, 2006)

If you want to sample the OB sound, go to a local dealer that has Martin Logan or Magnepan. Those are both thin-film speakers, so they will be every air-ier than OB cone speakers, but the overall lightness and transparency is still there.

GR-Research makes a few kits that are OB. Their OB5 and OB7 come to mind.

As for placement -- the acoustic theory is that they are velocity sources instead of pressure sources. A box cone speaker produces pressure, which then moves the air. This makes putting them in corners best (or near). The waves there are low velocity, but at highest pressure in the room. 

OB speakers are best placed farther into the room where the waves are lower pressure, but have more movement to them. Sadly, this can mean anywhere from a foot to several feet into the room for best quality sound. Hybrid designs that use sealed woofer sections but OB mid and upper range can be closer to the wall to get reinforcement of the bass, yet still sound light and transparent.

Hopefully this helps. I have a whole pile of parts in my basement for an OB build, but never got around to finishing it. Moving, then remodeling, and now day job have all got in the way 

Good luck and keep us posted on your project!


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## 1Michael (Nov 2, 2006)




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## mjcmt (Aug 30, 2010)

Michael,
That is an attractive looking speaker you built. And big too. Is the sound everything you hoped it to be? 

Do you mind answering a few questions about the design?
What drivers did you use? 
Does the x-over differ from one used with the same drivers in a enclosed or ported cabinet? 
When choosing the bass driver how do you choose one with adequate bass in open baffle?
Because of the potential airy sound can you get by w/ a full range and bass driver, without a tweeter?


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## 1Michael (Nov 2, 2006)

Michael,
That is an attractive looking speaker you built. And big too. Is the sound everything you hoped it to be?
No it sounded like trash so I gave it to a friend who uses it in the garage and we use it for outside movies where they at least sound OK. I would not recommend it...

Do you mind answering a few questions about the design?
What drivers did you use?
Hawthorne audio with their Xover.
Does the x-over differ from one used with the same drivers in a enclosed or ported cabinet? 
Completely different specifications. These kind of drivers cannot be used in a box.
When choosing the bass driver how do you choose one with adequate bass in open baffle?
See above answer.
Because of the potential airy sound can you get by w/ a full range and bass driver, without a tweeter?
It has a compression tweeter.


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## erwinbel (Mar 23, 2010)

mjcmt said:


> Fellow Shacksters,
> 
> I've built 4 sets of speakers over the years, and now I'm interested in an open baffle speaker design. But I've never even hear a set, so I don't know what to expect either. May I see photos of the ones you built and information on choosing drivers, x-over etc. Can you describe to sound they produce and about room placement for this type of speaker.
> 
> ...


You're always welcome to listen to my Jamo R909! Sure are nice speakers, punchy accurate bass. I think it's no easy speaker to build DIY. Presume you read the white paper with the explanation of the gradual roll-of of the midbass?

I also like the idea of the Orions, though I find them very uggly. There's one pic from a builder who modernised the shape and painted in white. A good alternative for the Jamo's. Probably sound even better. You know the two woofers will be horizontal and from Seas from now on?

I am in the proces of building speakers and subs for our HT. Speaker kit is designed by Troels Gravesen. He has a really cool OB also:
http://www.troelsgravesen.dk/OBL11.htm

The difference with the Jamo's is that the rather narrow baffle of the Jamo R909 makes it a neccessity to use two large woofers and also it needs a powerfull amp to shine. I use an Emotiva XPA-1 for each R909 that have no problems! The OBL11 will be far less power hungry thanks to the wide baffle and the special midwoofer and tweeter.

I am so convinced that normal boxes are flawed that I fell for the TQWT (Tapered Quarter-Wave Transmission line) also for our HT! Those drivers have to be free to breathe without stress to give their best...


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## mjcmt (Aug 30, 2010)

If I make it over the swamp to you neck of the woods in Belgium, I will stop in for a listening session. I have admired these speakers ever since they where released. Not only do I like the technical excellence, but the art and design really touch my soul, a trademark of Jamo.

That is an interesting point that you made "the rather narrow baffle of the Jamo R909 makes it a neccessity to use two large woofers". I always wondered how much baffle width plays into the design. 
Troels' speaker kit looks really good but I have no place for such a wide speaker. Where I can make compromises on such a design would be a question I need to research. An interesting note is that I used 2 similar Seas 5-1/4" Excel drivers in a MTM configuration in my own speakers and they have amazing midrange to tweeter integration and clarity for a box cabinet.

And you are correct, the Orion is quite ugly. I just liked the mid and tweeter used, similar to the 909, but didn't like the sealed bass cabinet they use. I would never buy a kit and just incorporate many of the ideas with my own modern baffle design.

Please post photos of your system w/ your 909's in play, as these are some of my favorite speakers ever made from a visual stand point. Now to hear them someday.


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## erwinbel (Mar 23, 2010)

The woods are long gone to make room for our house... I bought the (used) Jamo's for the open plan living space on first floor. But they are already playing for a year in our current dining room!


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## Ruben1 (Feb 20, 2012)

Just finished my first DIY project; open baffle speakers with horns. This is the write up I posted on a different site:
I have been an audio enthusiast for several years progressing from SS electronics to tubes and then going from CD’s to LPs as the primary source. For some time now I have been wanting to improve my speakers (Klipsch Epic CF 3) so a year ago I decided to make my own as I am fairly handy. Since I love the sound of horns I decided my speakers would incorporate them somehow. I also wanted something different than the box type speakers which are so common (to include the ones I had) so my research led me to the open baffle design which interested me both from a sonic point of view as well as aesthetics. 

I researched the open baffle designs and read as much as I could to make sure I understood all the relevant design parameters which must be accounted for in order to get a good sound (and not just have good looking speakers). 
The results are the speakers you see in the pictures. The drivers and crossover are from my Series 1 Klipsch Epic CF 3. The woofers are 10” and the signal is crossed at 1500 Hz. 
I am absolutely amazed how incredibly deep the base goes. The highs are crystal clear and blend perfectly well with the woofers. 
The whole thing took me 2 weeks to make with the horns taking half the time. Everything is solid red oak except for the baffles which are red oak plywood. The horns weigh 12 pounds each and are made of ¾ inch red oak wood floors which I had in the garage as a left over from when we redid the floors in the house. 
After listening for a while I tested the system using the Stereophile test CD3 looking to see how well the lower frequency response is and obtained the following readings using an SPL meter:
Frequency SPL
200 hz 98 db
160 98
125 94
100 87
80 85
63 82
50 88
40 85
31.5 75
25 70
20 64

In any case I wanted to share this project with everyone here.


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## Ruben1 (Feb 20, 2012)

Pics of my OB speakers:


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## GranteedEV (Aug 8, 2010)

Ruben, those speakers look very interesting. How low do you have the horn playing?



mjcmt said:


> I've built 4 sets of speakers over the years, and now I'm interested in an open baffle speaker design. But I've never even hear a set, so I don't know what to expect either.


There are as many different types of OB speakers as there are box speakers. The most universal tradeoff with OB, is that the driver will lose some of its bottom end. So a 6.5" driver that, vented might be good to 40hz, sealed might be good to 80hz, might only be useful down to 200hz in an OB. A lot more excursion and amplifier demands are required. 

That said, there are two kinds of OBs, large baffle and minimal baffle. The former aims to just get the "Rear wave" sound wheras the latter actually tries to use the OB's dipole radiation to control the interaction with the room.

I really don't think there's a _universal_ "OB sound" although it can be generally characterized by a more diffuse, deep soundstage. (don't get things confused though, this IS a coloration). Panel/Electrostat dipole speakers have very large dimensions, so they do suffer from narrow horizontal sweet spot and vertical destructive interference. 

The Orions mostly qualify as narrow baffle OB, in that the response is kept controlled by the dipole cancellations, until the 8" woofer begins to narrow response (keeping directivity controlled). The low 1.4khz crossover to the Seas Tweeter is really the only way that design can work, and it would be impossible without active equalization of the dipole peak and gradient rolloff. 

The opposite of an Orion, is something like the OBL-11 by Troels Graveson:

http://www.troelsgravesen.dk/OBL11.htm

which tries to AVOID the dipole cancellation that the Orion _wants_. The result is deeper bass extension and a passive crossover, but you lose the directivity control advantage. In essence it's more similar to a typical box speaker.

If I were doing an OB speaker, there is zero question which I would choose to build, John K's Nao Note with U-Frame woofers:

http://www.musicanddesign.com/NaO_NoteDetails.html


















IMO it's the most sensible design out there, as it REALLY hones in on off-axis response... though I do have a preference for metal cone drivers like them Seas Excels.


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## Ruben1 (Feb 20, 2012)

The horn is crossed at 1500 Hz so basically the woofers do all the work below this point and the horn and super tweeter take care of the frequencies above it. 

Also note that the side panels are on piano hinges so as to allow for adjustments. This will help me determine the most desired setting of the side panels to best match the speakers to my listening room. Since I just built these I have not finished testing them out fully to see which setting yields the best results to my ears.


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## Anthony (Oct 5, 2006)

Back when I had time (no home improvement projects or a kid  ), I had a design I wanted to build that was very similar to the NaO using BG Neo3. I had gone through a lot of tests and trial designs and that one turned out the be the best trade-offs for me.

That said, I didn't even consider horn loading anything! those look great, Ruben!

Oh and welcome to the Shack!


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## Ruben1 (Feb 20, 2012)

Thank you.

With regard to the side panels I found the speakers to sound best when they are open 13 inches. I am including a picture of what I mean by this to best visualize it. At 13 inches the panels are almost full open.

I am also including a pic from the front so you can see what they look like when set in this position.

On a related but different note I need some help interpreting the readings I took with the Stereophile CD3 test CD and my SPL meter.
I took readings with the panels set at different opening levels and recoded the values but I am not sure how to interpret the data. I have an interest in understanding, from an empirical data analysis point of view, what is taking place so any interpretation is greatly appreciated. 

These are some of the db readings per frequency measured:
*
Frequency* Panels Fully Closed Panels half open Panels Full Open 

*200* 97 97 95
*160 * 98 98 95
*125* 92 94 94
*100* 86 86 88
*80 * 86 86 89
*63*  81 82 83
*50* 88 89 90
*40* 85 88 89
*31.5* 75 75 78
*25* 69 70 71
*20 * 64 64 71


The room has the following dimensions: 12 ’ X 12’ X 9’. Not ideal to say the least but it is the only room I have to dedicate to music. I do have wall treatments. 

So, what are these readings telling me? 

Thank you for any and all interpretations.

Ruben


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## Ruben1 (Feb 20, 2012)

Hello everyone and happy holidays. its been a while since I posted here.
I want to share with everyone some upgrades I made to my original open baffle design. 

I added a simple grill to the woofers for protection and incorporated "horns" to the woofers as well as I love the sound of horn speakers.

The improvements in sound quality were modest but noticeable. The greatest perceived improvement was with imaging and base response. I suspect there now is a narrower sweet spot as far as listening positions in the room but for me this is OK as I have only one listening seat/position in my music room. Overall I am please with the results and will keep this modification. I suspect sensitivity was increased as well but have no objective evidence to be certain.

Once again I kept to using solid red oak in keeping with the rest of the speaker.

The rear flaps are still adjustable and I am having fun playing with them to adjust the base response to my listening room and taste.


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## Ruben1 (Feb 20, 2012)

Pics. Somehow they did not come up i the previous posting.


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