Neat stuff - this is the first I have heard of a double chamber reflex alignment. Thank you for posting.
You're welcomed. Hope it helps in a deeper understanding of this type of loading.
Output wise, the DCR is more like a normal BR than a bandpass.
Think of a DCR as a BR but with another resonance that is about 2x higher up. For example, if you tune your DCR for say 50Hz (-3dB), you will get another resonance at 100Hz.
It is this 2nd resonance that the DCR has an advantage. Since the resonance adds 3dB, you will get a 3dB bass boost at 100Hz if the response was initially flat at 0dB. This gives the upper bass more "punch". Instead of using a graphic eq to boost bass at 100Hz, the DCR does it acoustically.
Output wise, the DCR is more like a normal BR than a bandpass.
Think of a DCR as a BR but with another resonance that is about 2x higher up. For example, if you tune your DCR for say 50Hz (-3dB), you will get another resonance at 100Hz.
It is this 2nd resonance that the DCR has an advantage. Since the resonance adds 3dB, you will get a 3dB bass boost at 100Hz if the response was initially flat at 0dB. This gives the upper bass more "punch". Instead of using a graphic eq to boost bass at 100Hz, the DCR does it acoustically.
So what do we lose by doing this? And how far can we take it? Sounds a bit free lunchish without knowing anything about it.....as if one could use a 2in woofer and use 30 ports on the thing.<_<
There's no loss. Its essentially a BR with a second resonance. A little extra effort on the box construction, that's all.
Unfortunately, you can't add more ports to it. The design is limited to two internal chambers with 2 ports firing out.
Unfortunately, you can't add more ports to it. The design is limited to two internal chambers with 2 ports firing out.
well i built the crossovers and installed the drivers in the old Parts Express BR-1 cabinets......
the xovers were kinda big so i built them externally.....
the sound is wonderful, i do use a subwoofer but i expected that with the smallish cabinets.
thanks much Michael Chua for this fine xover design.
the xovers were kinda big so i built them externally.....
the sound is wonderful, i do use a subwoofer but i expected that with the smallish cabinets.
thanks much Michael Chua for this fine xover design.
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Hi mdynac
Glad you like the sound. With the right driver and an optimized crossover, there would not be any "harshness" or excessive sibilance. You should be able to make out good and bad recordings.
How are you running your new BR1 with your sub? Does your sub have a plate amp and adjustable crossover?
Glad you like the sound. With the right driver and an optimized crossover, there would not be any "harshness" or excessive sibilance. You should be able to make out good and bad recordings.
How are you running your new BR1 with your sub? Does your sub have a plate amp and adjustable crossover?
at the moment i run the sub with a modified plate amp. yes, it has variable frequency/gain
the sub is a Decware Deathbox II that i built
with the Decware DHM108B woofer
DECWARE / DHM108B 10 inch woofer
the sub is a Decware Deathbox II that i built
with the Decware DHM108B woofer
DECWARE / DHM108B 10 inch woofer
the br-1 is powered by an Adcom GFA-535 and i use the speaker level inputs on the plate amp.....
probably not the best way to do it, but it was the quickest....and i have yet to come up with a way to add an output to my preamp for the sub....without screwing up the sound.
probably not the best way to do it, but it was the quickest....and i have yet to come up with a way to add an output to my preamp for the sub....without screwing up the sound.
yes it does
at the moment i am using the preamp section of an Anthem Integrated 1 tube amp
it uses 12au7's
at the moment i am using the preamp section of an Anthem Integrated 1 tube amp
it uses 12au7's
In the event if your tube pre has difficulty driving the Adcom and Plate amp, you can use a Buffer before the Plate amp. This can easily be constructed with an opamp on a perf board. If it poses no problems, omit the buffer and connect the pre out to the Adcom and Line in of the Plate. Simply use a "Y" connector.
To integrate the BR1 to your Decware Sub, install a High Pass for the Silver Flute. A 2nd order Butterworth at 125Hz should do. Components 100uF + 12.5mH (use iron core, much cheaper).
Set Plate amp crossover to 125Hz. To check for correct polarity, flip the polarity switch on your plate amp. If there is no "polarity switch", you will need to connect the + wire to the woofer "minus" terminal and - wire to "plus". This will reverse the phase by 180 degrees. The difference is audible. You should get distinct upper bass or missing upper bass.
With these changes, your sub should integrate properly. Whether your sub has definition is a separate matter. Some are loud but boomy while others have definition. I have never owned a Decware sub before, so can't really comment. In case if there's boominess, its not the room. It is the woofer itself. Woofers with very good control are the ones that has define bass.
To integrate the BR1 to your Decware Sub, install a High Pass for the Silver Flute. A 2nd order Butterworth at 125Hz should do. Components 100uF + 12.5mH (use iron core, much cheaper).
Set Plate amp crossover to 125Hz. To check for correct polarity, flip the polarity switch on your plate amp. If there is no "polarity switch", you will need to connect the + wire to the woofer "minus" terminal and - wire to "plus". This will reverse the phase by 180 degrees. The difference is audible. You should get distinct upper bass or missing upper bass.
With these changes, your sub should integrate properly. Whether your sub has definition is a separate matter. Some are loud but boomy while others have definition. I have never owned a Decware sub before, so can't really comment. In case if there's boominess, its not the room. It is the woofer itself. Woofers with very good control are the ones that has define bass.
thanks for the info.....
i am only using the plate amp cause it was cheap......
its a TDA7294 build by Dayton.
i'm still not sure i like the single sub approach, and i especially don't like the current setup....thuis was just my first incarnation into the world of subwoofers....
the decware sub box was just a cool project to build while i was at my dad's wood shop one summer.....
i am still researching for a better sub setup....preferably one for each channel....
i will whip up a circuit this week to split the output of the preamp.....
i am only using the plate amp cause it was cheap......
its a TDA7294 build by Dayton.
i'm still not sure i like the single sub approach, and i especially don't like the current setup....thuis was just my first incarnation into the world of subwoofers....
the decware sub box was just a cool project to build while i was at my dad's wood shop one summer.....
i am still researching for a better sub setup....preferably one for each channel....
i will whip up a circuit this week to split the output of the preamp.....
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well gee, it seems that i have been running the sub without its zobel network connected....oops....
wow what a difference.....
wow what a difference.....
Would the woofers I have be more likely to be closer to your specs or manufactured specs?
Yeah they are really cool - don't know it they will ever be a sub, but getting really nice mid bass punch out of them.
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My SF W17 is the shielded version. It seems they don't sell them anymore. Only the unshielded version is available. If yours is unshielded, I'm not sure whether my T/S are similar.
However, if you're planning to use the shielded W17 for this DCR, the T/S don't matter. The measurements have already been made unless you want to redesign the enclosure.
However, if you're planning to use the shielded W17 for this DCR, the T/S don't matter. The measurements have already been made unless you want to redesign the enclosure.
Hello I think I can help you with the tweeter on your silver flutes. I built a two 10 years ago using the same woofer anda Seas tweeter with a 6 DB crossover on the woofers and a 12 DB crossover on the tweeters. The tweeter I used is no longer made but, Madisound gave me the replacment model number. I used the Seas 27TDFC (H1189) tweeter very nice with Audiocaps out thru the crossovers. Hopes this helps and sorry for being so late on this subject posting. Mr. Daniel
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