I made this topic to show my first home-made speakers. I came to this project because the form factor I had in mind can’t be bought. Since I didn’t have any experience with building speakers, I took a second-hand pair of my favourite speakers: the Hepta Gem. It’s a Dutch brand. I re-used the drivers, the crossover, the bass-pipe and the dampening material. And I could take it’s internal volume of 9 Litres as a reference.
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Then I started drawing in the program Geometry Expressions. This is a frontal view and a cross section.
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The speakers are 50 cm high, 35 cm wide and 7 to 16.3 cm deep. That’s about 20 inch high, 14 inch wide and 2.8 to 6.4 inch deep. The front is angled 15 degrees towards the listener, since I listen to them sitting very close to a wall behind my electric piano.
I used 1.8 cm (0.7 inch) thick multi-ply:
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When trying out my speaker, it didn’t sound very well. It turned out the multi-ply was vibrating quite a lot. This could be fixed by adding some reinforcements and self-adhesive vibration dampening material:
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Because of the 15-degree angle I couldn’t use clamps and ended up using 75 temporary screws for each speaker to tighten the glue joints. I later filled these holes:
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The end result without the speaker-cloth was already quite to my liking:
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For the speaker-cloth I made two wooden dodecagons (twelve-sided polygons) with a 45 degree angle on the sides.
The best way to attach the speaker-cloth turned out to make grooves with a multitool, fill these with glue and then push the speaker-cloth in the grooves. This way the speaker-cloth can be mounted without worrying the glue isn’t dry enough yet to hold the tension.
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This is the end result.
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Large image
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Large image
Then I started drawing in the program Geometry Expressions. This is a frontal view and a cross section.
The speakers are 50 cm high, 35 cm wide and 7 to 16.3 cm deep. That’s about 20 inch high, 14 inch wide and 2.8 to 6.4 inch deep. The front is angled 15 degrees towards the listener, since I listen to them sitting very close to a wall behind my electric piano.
I used 1.8 cm (0.7 inch) thick multi-ply:
When trying out my speaker, it didn’t sound very well. It turned out the multi-ply was vibrating quite a lot. This could be fixed by adding some reinforcements and self-adhesive vibration dampening material:
Because of the 15-degree angle I couldn’t use clamps and ended up using 75 temporary screws for each speaker to tighten the glue joints. I later filled these holes:
The end result without the speaker-cloth was already quite to my liking:
For the speaker-cloth I made two wooden dodecagons (twelve-sided polygons) with a 45 degree angle on the sides.
The best way to attach the speaker-cloth turned out to make grooves with a multitool, fill these with glue and then push the speaker-cloth in the grooves. This way the speaker-cloth can be mounted without worrying the glue isn’t dry enough yet to hold the tension.
This is the end result.
Large image
Large image
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That's a nice piece of repurposing and an imaginative use of space.
Very modernistic in style too - I love the 12-gon!
Thanks for sharing. 😎
Very modernistic in style too - I love the 12-gon!
Thanks for sharing. 😎
I was thinking the same. It is artful, and I want to listen to them. They look like they'd sound better than the original. I like your piano too 😉
I especially liked the description of your thought process, illustrated with pictures. The octo-shape speaker cloth is a really nice touch that works well with the wedge shape imho.
Are you planning to paint the cabinets or keep them in their current color?
Are you planning to paint the cabinets or keep them in their current color?
They sound musical, pleasant and mild with different kinds of music (classical, rock). And quite some bass, but not as much as my floor stands. I think they also sound detailed and have good soundstage.
They sound quite like the original. A translated review of those speakers:
The Gem is pleasant and mild, actually an omnivore that also manages to score in the low, but certainly not the most of the recording. A friendly curtain is raised, so that many details (eg accompanying figures in the second violins in Beethoven's Pastorale under Harnoncourt) remain in the primer. The opening fanfare in the Dansereye is not really sharp and the strings in Strauss' Im Abendrot misses the right attack. The distinction between the different recording locations can be made less accurately and I miss the feather-light touch and the spatial details in the opening chorus of the St John Passion. The beautifully recorded percussion in Rodeo and Dansereye is rendered less rich by the Gem. In the Mission there is overexposure, in the Gem it is precisely the underexposure that largely determines the character. It depends on what you choose as a designer, with Hepta apparently clearly preferring a small loudspeaker in a reasonable price range, which had to meet the most obvious criterion: a transducer that does not stand out in the first place because of really nasty traits, even if concessions have to be made in terms of transparency and definition. Hepta paid a lot of attention to the sound balance, because the sound image is homogeneous (Respighi), with a good, if not really exuberant stereo image (Pirates) and without specific instruments pushing forward. There is no abrupt gap in the middle / low: Fournier's cello also retains its fluid character in that range. Baspizzicati lack the dry core, but are not hollow or boomy, rather vague. It is nice that the pleasant character is retained with strongly increasing sound volume: this solid and generously dimensioned loudspeaker has enough reserves to convince in the noisiest passages. You also notice this with a good piano recording (Mendelssohn / Perahia) with the volume control in an extremely high setting. The piano sound does not become tinny or shaky, and the perspective of the recording does not change noticeably.
They sound quite like the original. A translated review of those speakers:
The Gem is pleasant and mild, actually an omnivore that also manages to score in the low, but certainly not the most of the recording. A friendly curtain is raised, so that many details (eg accompanying figures in the second violins in Beethoven's Pastorale under Harnoncourt) remain in the primer. The opening fanfare in the Dansereye is not really sharp and the strings in Strauss' Im Abendrot misses the right attack. The distinction between the different recording locations can be made less accurately and I miss the feather-light touch and the spatial details in the opening chorus of the St John Passion. The beautifully recorded percussion in Rodeo and Dansereye is rendered less rich by the Gem. In the Mission there is overexposure, in the Gem it is precisely the underexposure that largely determines the character. It depends on what you choose as a designer, with Hepta apparently clearly preferring a small loudspeaker in a reasonable price range, which had to meet the most obvious criterion: a transducer that does not stand out in the first place because of really nasty traits, even if concessions have to be made in terms of transparency and definition. Hepta paid a lot of attention to the sound balance, because the sound image is homogeneous (Respighi), with a good, if not really exuberant stereo image (Pirates) and without specific instruments pushing forward. There is no abrupt gap in the middle / low: Fournier's cello also retains its fluid character in that range. Baspizzicati lack the dry core, but are not hollow or boomy, rather vague. It is nice that the pleasant character is retained with strongly increasing sound volume: this solid and generously dimensioned loudspeaker has enough reserves to convince in the noisiest passages. You also notice this with a good piano recording (Mendelssohn / Perahia) with the volume control in an extremely high setting. The piano sound does not become tinny or shaky, and the perspective of the recording does not change noticeably.