Hi folks
Let me introduce a fast, cheap - and surprisingly fun & listenable project 😀
- a great weekend project !!! 😱
The driver is a modified 8" fullrange driver (Monacor SP-205/8)
The loudspeaker is designed to stand on the floor, and in a small room (up to about 15-16 m2 / 150-160 square feet). It is necessary to stand on the floor in order to get enough bass support. The baffle is suppported with an angle bracket on the back - which you can adjust up and down to find the vertical baffle angle, you think sounds best.
If you enjoy "live"-sound, this may just be the perfect fit.
In addition, the speaker is quite portable, and sounds better than small PC speakers, especially if you are playing loud, and just want a fair amount of bass ...
A little further images to stimulate the appetite...
What you actually do is to cut off the Whizzer-cone with a large pair of scissors. Cut in a spiral and cut several pieces. Do not worry - it's NOT difficult - and the job is easily done. The original function of the whizzer cone is to provide more treble - but whizzer cones in general sounds awful IMHO.
The Monacor SP-205/8 with original whizzer cone
Closeup: Monacor SP-205/8 without whizzer cone
You simply just have to saw a 18.0 cm / 7" hole for the Monacor in the middle of the plate, mount the driver, speaker terminals, cables and the hinge bracket with a single screw. I have attached a handle - your funkyness decides whether that's a good or bad idea 😀
Why is just the Monacor SP-205/8 used?
- When creating open baffle speakers, it's important that the driver you want to play bass has a high Qts, high sensitivity, low fs and a nice xmax. Normally a Qts around 0.7 is recommended as being ideal. A lower Qts makes the speaker roll off faster in the bass-region (ie less bass), a higher Qts causes the driver to roll off more gentle (more bass). Monacor SP-205/8 is in a German forum measured to have a Qts of about 2.5, which is pretty wild high.
"Normally" you can not make that narrow baffles (10" baffles), and get any bass. But this high Qts makes the speaker roll off very slow. The sensitivity is around 94 dB, so you can easily use even the smallest amplifiers (I use myself a TriPath 2020 amp with good results and high SPL).
I have tried to make an informal test of the low frequency curves using Online Tone Generator - Generate free low frequency tones to test your subwoofer.. And the level is disappearing below 80 Hz.
But, when playing music, I don't feel that I lack bass - what there is, is both sufficient and nuanced. Try these samples from Dieter Ilg's album "Bass" with acoustic bass here: Bass, Dieter Ilg (Arrang.) - WiMP
For each speaker, use
- 1 Monacor SP-205/8 full range driver (which you must modify - you must remove the whizzer cone). The device costs about 15-20 US$, and can be found cheaply on eBay - eine der größten deutschen Shopping-Websites
- 1 piece of wood, 25.5 x 25.5 cm (10" x 10") for baffle,
- 1 set of speaker terminals and some cable + screws.
- 1 angle bracket so the speaker can stand safely.
- Drill, Jigsaw, long scissors, soldering iron, screwdriver
Good luck - I'm looking forward for your feedback 😀
Let me introduce a fast, cheap - and surprisingly fun & listenable project 😀
- a great weekend project !!! 😱
The driver is a modified 8" fullrange driver (Monacor SP-205/8)
The loudspeaker is designed to stand on the floor, and in a small room (up to about 15-16 m2 / 150-160 square feet). It is necessary to stand on the floor in order to get enough bass support. The baffle is suppported with an angle bracket on the back - which you can adjust up and down to find the vertical baffle angle, you think sounds best.
If you enjoy "live"-sound, this may just be the perfect fit.
In addition, the speaker is quite portable, and sounds better than small PC speakers, especially if you are playing loud, and just want a fair amount of bass ...
A little further images to stimulate the appetite...
What you actually do is to cut off the Whizzer-cone with a large pair of scissors. Cut in a spiral and cut several pieces. Do not worry - it's NOT difficult - and the job is easily done. The original function of the whizzer cone is to provide more treble - but whizzer cones in general sounds awful IMHO.
The Monacor SP-205/8 with original whizzer cone
Closeup: Monacor SP-205/8 without whizzer cone
You simply just have to saw a 18.0 cm / 7" hole for the Monacor in the middle of the plate, mount the driver, speaker terminals, cables and the hinge bracket with a single screw. I have attached a handle - your funkyness decides whether that's a good or bad idea 😀
Why is just the Monacor SP-205/8 used?
- When creating open baffle speakers, it's important that the driver you want to play bass has a high Qts, high sensitivity, low fs and a nice xmax. Normally a Qts around 0.7 is recommended as being ideal. A lower Qts makes the speaker roll off faster in the bass-region (ie less bass), a higher Qts causes the driver to roll off more gentle (more bass). Monacor SP-205/8 is in a German forum measured to have a Qts of about 2.5, which is pretty wild high.
"Normally" you can not make that narrow baffles (10" baffles), and get any bass. But this high Qts makes the speaker roll off very slow. The sensitivity is around 94 dB, so you can easily use even the smallest amplifiers (I use myself a TriPath 2020 amp with good results and high SPL).
I have tried to make an informal test of the low frequency curves using Online Tone Generator - Generate free low frequency tones to test your subwoofer.. And the level is disappearing below 80 Hz.
But, when playing music, I don't feel that I lack bass - what there is, is both sufficient and nuanced. Try these samples from Dieter Ilg's album "Bass" with acoustic bass here: Bass, Dieter Ilg (Arrang.) - WiMP
For each speaker, use
- 1 Monacor SP-205/8 full range driver (which you must modify - you must remove the whizzer cone). The device costs about 15-20 US$, and can be found cheaply on eBay - eine der größten deutschen Shopping-Websites
- 1 piece of wood, 25.5 x 25.5 cm (10" x 10") for baffle,
- 1 set of speaker terminals and some cable + screws.
- 1 angle bracket so the speaker can stand safely.
- Drill, Jigsaw, long scissors, soldering iron, screwdriver
Good luck - I'm looking forward for your feedback 😀
Last edited:
The Betsy is another great candidate for similar low cost OB applications. No mods needed, perhaps slight BSC and it sounds just great....almost full range.😀
I can see the pictures just fine.
FWIW, I think this build is a great example that shows we sometimes let the research, modeling, and measureing get in the way of just having some fun and, above all, listening to the music.
FWIW, I think this build is a great example that shows we sometimes let the research, modeling, and measureing get in the way of just having some fun and, above all, listening to the music.
Last edited:
Posted by Fastbike1: "FWIW, I think this build is a great example that shows we sometimes let the research, modeling, and measureing get in the way of just having some fun and, above all, listening to the music."
Beautifully stated!
Mario
Beautifully stated!
Mario
Agreed toobhed.
What's stopping anyone from doing this with larger drivers? I think a 15" Audio Nirvana will produce much more bass and can easily be moved from room to room.
What's stopping anyone from doing this with larger drivers? I think a 15" Audio Nirvana will produce much more bass and can easily be moved from room to room.
Looking at the specs for the Audio Nirvana 15 cast frame... well, it should work pretty fine. If I had the money right now, I would give it a try 🙂
@Juspur,
Have you seen pictures before but cannot now?
Perhaps the images are being blocked by a browser setting or firewall.
Member
Joined 2009
SonicWall firewall is blocking the pictures for me.
They have listed the image host as "Pornography"
They have listed the image host as "Pornography"
SonicWall is right: no speaker grilles, and you can see both sides... 😀
Maybe it should be named "The stripped naked speaker" 😉
Member
Joined 2009
Paid Member
- Status
- Not open for further replies.