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Multi-Way Conventional loudspeakers with crossovers

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Old 18th April 2014, 09:42 AM   #1221
Rudolf is offline Rudolf  Germany
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Your bass modules "hide" very well behind the acrylic baffles. How much is their unusual orientation (perpendicular to the other baffle) the result of aesthetical considerations and how much the best acoustical position?
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Old 18th April 2014, 10:59 AM   #1222
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Originally Posted by Rudolf View Post
Your bass modules "hide" very well behind the acrylic baffles. How much is their unusual orientation (perpendicular to the other baffle) the result of aesthetical considerations and how much the best acoustical position?
It is both: aesthetics and acoustics. After hearing Gradient's open baffles I decided to try this position, which turned out to "work" in Finnish speakers. Before I believed such orientation will result in no bass in the seating place. However due to room acoustics and wave reflections from walls and cupboard it really works. However I spent a while on choosing their best position and angle...
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Old 19th April 2014, 03:40 PM   #1223
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Do you know the right Thiele Small parameters for Alphard HW 1800.
I have read Qts to be 0,46 and Fs 27.And Qts 1,04 and Fs 29.
Prices 55 eur and 195 zloty.

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Old 20th April 2014, 07:21 AM   #1224
DrBoar is offline DrBoar  Sweden
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I read about the Wharfedale SFB long time ago but thought it was an outdated design. Then I read Troels Gravesens new interpretation of the design and got intrigued. I have a scruffy packing crate plywood sheet 1200x1600x12mm. I have eight Seas alnico 10" woofers with a Qt of 0.7 and Fr of 34 Hz. And several other Seas vintage drivers. To that I bought 12 meters of wood with the cross section 120x21mm to the cost of about 15 dollar.

Building and Measurements
I cut the board in half and cut holes for the drivers, then I added a 120 mm deep frame around the perimeter of the boards as well as some extra braces with leftovers.

Click the image to open in full size.

I screwed the driver in place with 104 screws!
Added a crossover consisting of electrolytic capacitors from West-Germany.
So 4 Seas 25TV-EW per side then 1 Seas 21TV-EW capacitor coupled and finally 3 of the Seas 9TV-LG that is mounted on a metal bracket angling the outer tweeter about 15 degrees to the side.

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Mounting the drivers on the baffle lowers the resonance from 34 to 28 Hz. Two impedance peaks at 55 and 70 Hz turns up as well

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A Omnimic measurement just in front to one of the dust caps show the dips in response at 55 and 70 Hz otherwise good response from 30 to 300 Hz

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Listening test
Room 6x4 m with the speakers on the standing about 1 m in front of the shorter wall.
Equipment: Philips CD473 NADC320 BEE, the cheapest cables and loudspeaker cables with visible oxidation.
Reference equipment: Maranz CD5001, Cambridge C500 SAnsui BA-F1 Stridbeck TLS (think IMF80) Decent cables.

Music NADs first test CD, BIS CD-232Kroumata Percussion Ensemble, Laleh and Rammstein.
I have heard the KODO drummers from the NAD cd and the Kroumata group several times live as well as heard it using my large TLS speakers. I had little expectations for these flimsy baffles.

To my surprise it sound really good, the baffles connect to the room in a way that I last had at home with DIY Klipsch corner horns. The piano on the NAD CD is in the room more so than how it sound with the large TLS. The percussion on Kroumata and Kodo is better with the baffle closer to what I remember of live sound.

Lalehs singing and acoustic music is portrayed well. Finally Rammstein at close to concert level to get that physical experience. Loud and clean and only about 2mm cone motion. Probably not much bass below 50 Hz or so.

I have to build proper baffles, a modern interpretation of the SFB. Drivers from Norway, eight of them per set adding the kick, the name of the speakers has to be Sleipnir.
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Old 20th April 2014, 08:54 AM   #1225
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båndsei - the higher Qts values are for 8 ohm version, which I am using and is preferable for OB, and lower for 4 ohm.
Some users in Poland have measured these speakers and Qts was even higher. It is low cost speaker which I think now is no longer produced.
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Old 20th April 2014, 08:59 PM   #1226
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These speakers were inspired by MJK's open baffle article at Quarter Wavelength Loudspeaker Design. The wide-range drivers are Radio Shack RS 40-1297. The woofers are vintage Magnavox. I used first ordered high-pass and low-pass filters tuned to 1kHz and 250Hz respectively. This is meant to equalize the predicted 500 Hz peak due to the baffle width. They could probably use a sub-woofer and super-tweeters, but I like the sound pretty well.
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Old 21st April 2014, 02:53 AM   #1227
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Pretty cool OB's Paul. I bet they make nice music. I wish Radio Shack was still selling drivers for us DIY'ers to play around with.
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Old 23rd April 2014, 01:06 AM   #1228
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Very nice NaO Note implementation with a hint of 'CS2' flavour by SAC


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Old 23rd April 2014, 09:45 PM   #1229
SAC is offline SAC  United Kingdom
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I'm honoured!
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Old 25th April 2014, 06:56 PM   #1230
baco99 is offline baco99  United States
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I am humbled by some of the amazing works of art that are on display here. I'm an active AudioKarma member and just rediscovered this site after a long hiatus. Pleased to see that OB experiments are at the top of the heap!

I was inspired by a similar AK thread and used a pair of these unique Morel Integra-300 coaxial drivers on a piece of leftover OBX. I was amazed at how much I liked what I heard!

I've decided to take the OB concept further and build some baffles out of hardwood plywood. I'm still very confused about how to manipulate the bass frequency response for the best effect. If anyone can explain that in "street language" that would be great!

First question, should I center-mount the drivers on the baffle about 32" A.F.F. O/C from the floor? Or should I "mirror" the drivers to one side or the other?


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For a crossover, I am using a very rudimentary "filter and choke". All drivers are left unattenuated for now. Once I get the baffle figured out, it will be time to tweak the crossover.

Last edited by baco99; 25th April 2014 at 06:59 PM.
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