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OMFR Speaker - One More (folded-horn) Full-Range Speaker system

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Had been browsing the web for good speaker designs and was intrigued by the concept of horn speakers. Thought I would go ahead and make one just to see if the claims on the web were true or not  (very high efficiency, no cross over distortion, great sound in th mid range, and bass up to 30-50 Hz without woofers) . The designs on frugal-horn.com seemed well thought out and the Spawn family seemed to be good performers especially after the glowing reviews on equivalent speakers. I was planning on recycling drivers (3 inch or 4 inch speakers) that I already had so therefore selected the least wide Spawn speakers.

The picture shows how the speakers turned out. Wife likes em! Will post a video later on.

Printed the plans out. I needed 18 inch wide panels for the sides and 5 1/8th inch wides for the baffles and dividers etc. Closest were 16 inch wide and 5.5 inch wide. So decided to get enough of the 5.5 inch white MDF panels to make one speaker. Also bought some nice plywood and Lowes cut it for me to 18 inches wide. Was simpler to stick to the original 18 inch dimensions otherwise I would have to recalculate the internal baffle dimensions.
 
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fretted1 year ago
Awesome Ible thanks
danamark1 year ago
Haven't seen a folded horn like this in years, was very popular in the 50s. You can find old magazines where people built them into the house walls as I recall. That over priced Bose folded waveguide ad always reminds of these old folded horns.
http://tinyurl.com/d2m29sh
Good Gosh i remember these wow they sounded Amazing and were SUPER expensive in the 70's used !

Great Ible i'm gonna build me some of these ...
Great link - Check out the page a couple pages down for 'Color Computer monitors less than 800$'
abizar (author)  danamark1 year ago
Thanks for sending the link. Yes, does look similar except the volumes on the Bose are substantially lower. Confession - currently I have Bose Acoustimass 5 speakers, but the ones I made sound much more better. I just hooked up a cheap Tripath chip based amp from Leipai (less than $20) and the speakers suddenly came alive! Quite unexpected. Am tempted to try a version of these speakers which can handle larger 8 inch drivers.
databoy1 year ago
95% of the cost of commercial box speaker manufacturing is in the box. 5% is in the drivers.

An exponential folded horn is probably the most efficient design and the most difficult to manufacture.There are a number of reports that state stepping the sides to replicate a folded exponential horn makes no perceivable difference to the bass frequencies.

The horn design you used is a proven design and will provide more bass drive for a lower power than a standard sub-woofer box.

What will improve the sound is the box material. Regardless of the price, commercial manufacturer's will not use plywood because the material is too resonant and too difficult to quality control the bass. The best material is HDF. If you cannot find HDF; use MDF or particle board. Instead of using stepped corner pieces, an easier method is cut the corner pieces so one piece fits at a 45 degree angle and it cuts down on the overall weight of the box.

A sub-woofer box will not improve the bass response, but it may give you a honky bass that a lot of people perceive as lower bass. You could use the same box and use a better quality driver, try Parts Express, that would give you a far superior sound than any sub-woofer design. You can also try inserting anti-resonant material at the mouth of the horn.
pdub77 databoy1 year ago
I was wondering about the choice of materials while reading this. Very curious about this design and just got started playing with pro audio again. Could be good or bad timing, depending on how you look at it. But I was always told the same, that MDF was the way to go because hardwoods are too resonant.
abizar (author)  databoy1 year ago
One of the two speakers has the internal baffles, speaker bottom, top, back and speaker front panels of MDF. Had a pile of ready-to-use 5.5 inch wide primed MDF 6 feet long panels from Lowes (typically used in shelving). The left and right side of this speaker is plywood.
The second speaker is all plywood.
So would be a good way to test if MDF has an impact on sound quality by comparing the two.
On the stepped corner, guess it attentuates high frequency more effectively than a smooth panel so you get more bass reflected out.
I hooked up a cheap T amplifier (http://www.amazon.com/Lepai-TRIPATH-TA2020-Stereo-Amplifier/dp/B003P534SW/ref=pd_ys_sf_s_172282_a1_6_p) and the sound quality us stunning and loud (from 10 W RMS)! Do not see a need for a sub-woofer. Honestly, am really loving these speakers.
Am toying with the idea of making another pair with 8 inch drivers that I had bought a while back from guess what - Parts Express! These are not Fostex but some other full ranges with a wheezer cone that I was going to use for in wall speakers.
Skymeat1 year ago
Really cool! This is the first I've seen the design - And I'd love to hear them.
shobley1 year ago
As a recovering audiophile, I can attest to the deep psychological impact of spending a day or two building something to improve the sound. I bet it's just as strong as spending very large amounts of money.

They are very cool looking though, and if I were to build them I'd have to figure out a way to make the baffles visible.
abizar (author)  shobley1 year ago
Neat idea! Acrylic side panels would be phenomenal but the cost would be astronomical.
I have seen some well done acrylic cabinets, including at least one folded horn design previously. The "true audiophile" will not stand for the use of such material for dozens of reasons. Mainly, rigidity and unwanted coloration from resonance. But, speakers are kind of a personal thing. As far as I'm concerned, if you want them, make but. Just always remember that there is time proven reason for component selection, materials, and construction methods for those who take such things in esoteric doses.
privatier1 year ago
Since your speaker is quite narrow, it could be used as a starting point for designing a woofer which can be placed under the sofa - a design with a high WAF (wife-acceptance-factor).
abizar (author)  privatier1 year ago
Folded horn woofers are quite common. But a full range of a single driver is where the magic is. Unfortunately, my wife is in the process of rediscovering her Anya and Clannad collection on the new speakers! And she has been dropping hints that another pair for the living room might be ok (the ones I made are in our finished basement).
I am not saying it's BAD.....

Everything has some fundamental worth.

I have designed my speaker systems around what I call, "Fundamental Resonance" - which can be envisaged as hanging a wooden or plastic rule off the edge of a desk and "plucking it". A long overhang produces a lower resonant frequency, and a short overhang has a high resonant frequency.

Thus large speaker cones have a natual low frequency resonance and small speakers have a high frequency resonance.

Thus I design my speaker systems to provide a full range, based upon their natural resonance, rather than pushing a little speaker to do full bass, or a bass speaker to do higher octave notes - with a little overlap between them all.

I also do not agree that these are a high efficency design, as most of the "filtering"(?), comes from drag, resistance, reflections and turbulence, as the waves of variable frequencies churn through the maze of square edged and cornered pathways.

A true HORN has a fixed frequency resonant driver and a tube of resonant length, that ends in a full bell mouth ending.

While confined to a very narrow frequency range for optimum energy input to power output, that is where pure effiency lies.

Nor can one make a little speaker, resonate like a large speaker and vis versa.

What I am saying is that everything is a compromise, in time, energy, resources, space, weight, complexity, cost, materials availability, production facilities, tooling, acceptable trade offs, etc., etc., etc.

I do think this is an interesting solution to make ONE speaker, cover a broader range of frequencies than normally possible.

It's principle issue, I feel may come from the minimal supplies post war europe, where timber was easier to get than electronics., and people sought novel ways to improve the limitations of the available and costly speakers on the market.
darqdean1 year ago
Nice looking job. One minor observation regarding the folded horn section is that from the photographs it does not look like the cross-sectional area of the horn is gradually increasing (ie the walls look to be parallel). Did you use a mathematical formula to calculate the horn size or was this by eye and ear trial and error (nothing wrong with that of course as it will also produce the right result).
abizar (author)  darqdean1 year ago
Yes they are parallel. I coped the design from http://www.frugal-horn.com/spawn.html and as these based on MathCad analyses. A gradually increasing cross-section might help but again I was experimenting to see if the original design worked or not. Maybe a brave soul would like to try your suggestion!
Ah, that link is very informative, thank you. Now I've scanned through the patent I can see how this (manifold solution) reduces the high-frequencies acoustically without an electronic filter - a cunning solution that I may employ on my next speaker build.
profpat1 year ago
this is a nice project, adding a small piezo tweeter would help for the high notes of the spectrum.
abizar (author)  profpat1 year ago
Yes, quite a few commercial versions of these type of speakers do include a tweeter. Example, http://www.lovecraftdesigns.com/speaker_benES.html and http://www.soundscapehifi.com/cain.htm#studio-series. But then I will need a capacitor as a crossover to pass high frequencies to the tweeter.
This is very cool. I love the sound maze. I do not know its technique term for it but I do know it helps separate different frequency by bouncing the sound in an echo effect and reflection effect. What Kind of driver did you use? Is it a high mid range or a low mid range??

I am a troller audiophile, I do not work on anything but I watch other work on D.I.Y. stand alone or book shelves speaker.

You should try to make yourself a passive crossover so you can limit range your audio. A cross over does better in the long run with music since you can channel different fequency to improve an audio range.

I love how your speaker stands out. Very old american look with a modern audio take. :)
abizar (author)  The End of A Heartache1 year ago
They are full range Fostex drivers from a very popular powered speakers the FOSTEX SPA11 that were used a lot in auditoriums etc as fill in sound. The nice thing about these horn speaker designs is that you do not need multiple drivers and therefore no crossover to split the frequencies into different drivers. Supposedly prevents sound being screwed up by crossover artefacts. They do sound different from my regular speakers and nicer.
pekar1 year ago
Nice job!
After all the work you put into these, you should try better drivers.
I'd try a Fostex from Madisound.com
abizar (author)  pekar1 year ago
The drivers in the speakers are Fostex, I harvested them from a Fostex SPA11 powered/amplified unit that had issues with its integrated amplifier. The model number on the back of the driver is 10F07C. Could not find info on the web. Bet that better Fostex drivers would improve the sound.
I like the design of the speaker, but have a question. Why did you make the corners solid? Doesn't that extra weight on the top make the speaker more easy to tip over? I would think using 2" lengths except for the one 1" one would accomplish the same thing with much less weight for the top corner. You could leave the bottom corner as is, to lower the center of gravity. Others have suggested adding a woofer for more pronounced bass. If you did, where would you place the woofer?
abizar (author)  thinkpadt301 year ago
The original design at http://www.frugal-horn.com/spawn.html claimed that the bass is substantially enhanced. Did not believe it therefore built just one speaker and was a bit surprised at how low it went and how good the overall sound is. Therefore decided to build another one and spend some time finishing it. Don't think I need a subwoofer as I mostly listen to acoustic instruments and vocals. The subwoofer could be a separate box.
About the tipping over, yes you are right, might add a broader base to prevent that.
Re-design1 year ago
Nice job!
rimar20001 year ago
Inspired from your design, I did another similar. See the image. The grey zones have tilt walls in the corners to avoid (or dismiss) echoing. They could be curves, I think that it would be better.

Forgive me, I can't add the image because the uploader fails. The only change respect your design is that the walls are not perpendicular, they are tilt, forming a growing throat.
abizar (author)  rimar20001 year ago
From your description, that sounds like an interesting design. Would like to see the pictures if you get the uploader to work.
I tried again, without success. Maybe I should report it as a fault.
abizar (author) 1 year ago
Could not hear bass below about 40-45 Hz though a 10 year said she could. Getting to 20 Hz at high volume might need a sub-woofer or a bigger driver (an 8 inch driver would do better than the 3 inches I used). Like your idea about two drivers but then you would need quad amplifiers for a stereo set up. The upper and lower ports on the speaker do add the sense of being with the performers. Hard to describe but it adds to the listening pleasure.
spylock abizar1 year ago
One thing about it,you have enough room for a bigger driver,as well as a woofer if you like.I saw the same type speakers in a local store the other day,with an FM receiver at the top.It wasnt but 79.00 and a space saver for sure.
onlinebeat1 year ago
coolest speakers i have ever seen. well done!
rimar20001 year ago
Clever design, and well worked!
Impressive build...

Do you find you get any sort of decent kick from them?

One of my biggest gripes with single driver setups, you can't replicate a band sound with them...

Though a separate sub would take care of the missing chunks.

The design's interesting, I'm sort of looking at it and wondering would two drivers work better, basically the same baffling on each with a divide between.