Foam Core Board Speaker Enclosures?

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Lance in Foam Core with RS100-4

I have always been a fan of Scottmoose's Lance TL, designed for the FF85wk. I decided to have a go at in foam core. It is a very small speaker about 10in tall x 7 in deep x 4 in wide. Plan for it is here:
http://wodendesign.com/downloads/Woden-FF85-Lance-Laby-1v01-180214.pdf

About 1.25 sheets of 30x20in foam core is enough to make a pair of speakers. The pieces are relatively easy to cut as they are all rectangles. I added some bracing which is needed for thin foam core but not if using 1/2in ply.

Here is the build process (took 2 hrs to make)...

Cut all the pieces for a pair of speakers:
454993d1419195757-foam-core-board-speaker-enclosures-lance-build-01.png


Glue walls and dividers together (note cardboard layer for driver mounting):
454994d1419195757-foam-core-board-speaker-enclosures-lance-build-02.png'


Finished - a smart looking desktop speaker:
454995d1419195757-foam-core-board-speaker-enclosures-lance-build-03.png


Here are the measurements 6 in away from a back wall:
454996d1419195757-foam-core-board-speaker-enclosures-lance-rs100-4-hd.png


Here is the measurement far from a wall:
454997d1419195757-foam-core-board-speaker-enclosures-lance-rs100-4-hd-no-wall.png


Here is the output from the rear TL vent:
454998d1419195757-foam-core-board-speaker-enclosures-lance-rs100-4-meas.png


I can highly recommend this build - sounds very nice. Just don't push low frequencies or you approach 100% HD below 50Hz. :)
It sounds very nice, the bass extension is around the 80Hz range and although is not quite as deep as a 0.4x Karlsonator (70Hz), it is very satisfying to listen to. The intended use is as a desktop computer monitor 6 in away from a back wall so there is no need for BSC. A fun speaker and very easy to make.
 

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I like that small design. Would anyone be able to comment on this vs. the Kanspea that Madisound sells? The Kanspea cabinets add very little cost as part of the kit when buying the drivers. These would be for my office, driven with a 3116 amp, or possibly my other daughter would take these to school for her dorm room.
 
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Joined 2012
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I like that small design. Would anyone be able to comment on this vs. the Kanspea that Madisound sells? The Kanspea cabinets add very little cost as part of the kit when buying the drivers. These would be for my office, driven with a 3116 amp, or possibly my other daughter would take these to school for her dorm room.

You probably should ask that in the Woden 3 inch designs thread. I haven't tried any Fostex drivers so can't comment. The TL would sound better is my guess. Although I have also designed a dual chamber reflex (DCR) for the RS100-4 in the exact same footprint (very small) as the above box and it reaches deeper to 67Hz fb. Output will be down a bit but for near range at a desk it's not an issue. I can post plans if you are interested. I was actually going to build FC prototype but haven't had a chance yet.
 
These are terrible photos taken with my phone of my MLTL builds.
They're out of 3mm MDF as foamcore is elusive and expensive here.
I tried one in stereo and really liked it, so I built another and am running each as a single channel driven by two Sure TA2024 amps.
I am waiting for two Sure 3116 amps to try. They are hanging in my workshop.
Thanks X.
Paul
 

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OK - I'm going to have to do some reading in this thread. I'll be working from a temporary office for several months, and was trying to decide what I can do, (on the cheap) to have halfway decent sound - without building something elaborate.

I have a couple of Dayton Audio RS75-4's laying around, looking for something to do, Those, with a cheapo class D might fit the bill perfectly. :D
 
Try building the mini Karlsonators 0.4x scale with your RS75's. That is an easy, fast project that sounds great.

Thanks for the suggestion. Time to use my Google-foo. I'll post back if i make something presentable, (that doesn't look like a grade school art project):D

I can almost feel the hot glue burns on my fingers already. ;)
 
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Founder of XSA-Labs
Joined 2012
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Founder of XSA-Labs
Joined 2012
Paid Member
X

Did you or anybody else look at how a CLD foamcore box stacks up to panel damping as discussed in various BBC papers?

http://downloads.bbc.co.uk/rd/pubs/reports/1977-03.pdf

Pnix,
Thanks for the link to the paper - I have not seen it before so can't comment on comparison to BBC results. However, I have found that a CLD formed using two layers of foam core sandwiched with a thick layer of latex caulking compound dramatically reduces harmonic distortion in a foam core horn. It also increased the absolute SPL level because less of it went into vibrating the structure.

More info here:
http://www.diyaudio.com/forums/full-range/259293-prv-5mr450-ndy-fast-applications-13.html#post4036324

Without CLD:
434942d1408971865-prv-5mr450-ndy-fast-applications-tractrix-no-cld-old-eq.png


After CLD applied:
434944d1408971865-prv-5mr450-ndy-fast-applications-tractrix-cld-new-eq.png


What was neat was that I was playing music through the horn as I was applying the CLD panels and could hear it transform in front of my ears. Very cool and definitely something to be aware of as a tool to extract the most performance from a speaker. It may not be as dramatic with a box, but a horn, it makes all the difference.