I have had success with two DVC 10" woofers ported up high... run on a four channel 24v amplifier board. So I know its possible.
Well if you use a mountain bike the most sensible solution is to use the integrated subwoofer-wheels powered by a crank driven generator to the D-class amp housed in the downtube. You get low windage, two 18" subs, green prestige for being leg powered and an extra workout. Any other solution are just ridiculous in comparison. 🙂
I have a hive theory... lots of smaller sound systems tied together. I've had 24v four channel class-d amps pushing two DVC 10" woofers fill a 50' x 50' section of the street. But that was dragged by a trailer. Trailers on these bike rides are awkward because of the crowds. Besides, its the bicycling that we love mostly.
I'm interested in a pro audio bass guitar speaker. Are there any affordable ones?
That would require close formation riding, for maximum gain the sources must be within 1/4 wavelength of each other.
Bass guitar speakers generally are more "full range", and built for more harmonic distortion than pro-audio drivers.
What is "affordable" mean to you in dollars?
Been doing multiple sound systems for years... its incredibly successful. Yes, we ride in a group that allows people to ride within our cloud of speakers... its an acoustic trip to ride through it.
Affordable is low end gear... sub $100 drivers and sub $100 amps. I only do these rides once or twice a year...
Were these mounted on the bike or trailer.
otherwise the bass extension likely pretty good.
I'll assume you are looking for more volume/SPL
that is where the tradeoff is
home stereo type subwoofers can go deep.
but efficiency is low.
pro sound drivers will provide much more SPL
with the available wattage
but they wont go as deep.
any other solution for more SPL and deep bass
just involves more power.
getting more power is easy.
the tradeoff is battery life.
you either run a boost converter
just using 12 volt car amps.
or a bridged amp will provide
more voltage swing.
both solutions just draw more current.
otherwise another old school trick
for SPL. comes from the old
car audio SPL competitions.
They use high tuned 6th order bandpass
All rear rack on bike.
Ooooo thats interesting. As is the european opposing woofer "boominator" movement a few years back.
opposing drivers likely isobaric.
and yes it has been done with bandpass.
so isobaric makes the box about half the size smaller.
tradeoff is less efficiency.
or about half the efficiency
otherwise just using a single speaker.
6th order bandpass tuned for max SPL.
single driver wont have efficiency losses
box size will be what it is.
little larger.
and yes it has been done with bandpass.
so isobaric makes the box about half the size smaller.
tradeoff is less efficiency.
or about half the efficiency
otherwise just using a single speaker.
6th order bandpass tuned for max SPL.
single driver wont have efficiency losses
box size will be what it is.
little larger.
I am a furniture builder by trade, the cabinet construction is easy for me. Could you see a 6th order bypass being worked into a box shaped somewhat like this? (the speaker is drawn in as a conventional sealed box) And could I find a DVC driver for the design, or perhaps a mono class-d amp with some step-up? I intent to carefully build the box with internal stiffing supports to keep the walls from playing. The box can be as wide as it needs to be to make the proper volume. and I can tie the bottom of the box to the wheel axle.
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What dual voice coil speaker model are you looking at?
I will assume around 83 to 85 dB
I was looking at maybe 93 dB drivers.
as a pair for 96 dB
So big difference in SPL vs Wattage
To get to 110 dB
one system would need maybe 100 to 130 watts
other system only 25 to 35 watts.
Be interesting to look at numbers.
Since basically trying to weasel
around 3 cubic feet on the back of a bike.
If possible.
Believe the trick is similar to your design
getting most the volume to hang on
both sides of the rack.
trying keep weight or balance
down low
I will assume around 83 to 85 dB
I was looking at maybe 93 dB drivers.
as a pair for 96 dB
So big difference in SPL vs Wattage
To get to 110 dB
one system would need maybe 100 to 130 watts
other system only 25 to 35 watts.
Be interesting to look at numbers.
Since basically trying to weasel
around 3 cubic feet on the back of a bike.
If possible.
Believe the trick is similar to your design
getting most the volume to hang on
both sides of the rack.
trying keep weight or balance
down low
This is what I used before.
https://www.parts-express.com/Dayto...ngRngrA7WECPRtPAcbjQBtcfDm1rurUxoCTlwQAvD_BwE
My simple reasoning is its easy for me to have two channels from a standard class-d amp board feed into it. And attempting to avoid the weight of a second driver.
My box design has a fair bit of the volume above the rack still... but it will be good to get some of the mass down low.
https://www.parts-express.com/Dayto...ngRngrA7WECPRtPAcbjQBtcfDm1rurUxoCTlwQAvD_BwE
My simple reasoning is its easy for me to have two channels from a standard class-d amp board feed into it. And attempting to avoid the weight of a second driver.
My box design has a fair bit of the volume above the rack still... but it will be good to get some of the mass down low.
I think you're heading in the right direction with the "Stonehenge" box design, maximising volume and attempting to get some weight low. I'd take the same approach if focusing on a single purpose bike-specific design.
You could use two 10" drivers, one on each side mounted low... or even four 8" drivers, two each side mounted low or diagonally offset.
At this point I'd suggest stepping back and considering the system holistically (including cost!) - the output of your chosen amp will inform the best approach for driver configuration.
If using a two channel amp that can drive a 2ohm load per channel, you could go for the 8 smaller drivers at 4ohm each. Or a single channel amp might only want to be loaded with two larger drivers.
Weltersys mentioned voltage swing earlier, and matching the amp to driver makes sense - tuning the system so you hit the driver's mechanical limit at the same time the amp hits it's maximum output voltage.
One last thing - do you have any parts on hand now you wish to repurpose, or is this all starting from scratch?
You could use two 10" drivers, one on each side mounted low... or even four 8" drivers, two each side mounted low or diagonally offset.
At this point I'd suggest stepping back and considering the system holistically (including cost!) - the output of your chosen amp will inform the best approach for driver configuration.
If using a two channel amp that can drive a 2ohm load per channel, you could go for the 8 smaller drivers at 4ohm each. Or a single channel amp might only want to be loaded with two larger drivers.
Weltersys mentioned voltage swing earlier, and matching the amp to driver makes sense - tuning the system so you hit the driver's mechanical limit at the same time the amp hits it's maximum output voltage.
One last thing - do you have any parts on hand now you wish to repurpose, or is this all starting from scratch?
Only a slew of high end 18650 batteries that I'd be interested in using. Outside of that, I'm without parts.
If you want to use the higher frequencies from the woofer, you don't want a bandpass box.
Bandpasses are more complicated and can get finicky, but 4th order is more forgiving than the other varieties and is relatively straightforward. You still need to model it though, and make sure you're achieving something useful with the extra trouble.
If you're trying to keep things small, 4th order is typically more suitable from that aspect also.
Bandpasses can mask driver distortion, making it harder to tell when things are going south. With a 4th order and relatively low power, that should be less of a concern, but still something to be aware of.
I'm feeling like keeping it simple is the right move.
What about, two of these, as a sealed, dual opposed woofer bipole design, run from a stepped up mono class-d amp. Would that need to be 2.4cf x2?
https://www.parts-express.com/Goldwood-GW-1258-12-Pro-Woofer-290-382
Perhaps I could run two of my 12v three 18650 battery holders in parallel to make sure I have enough amps for the stepped up mono.
https://www.18650batterystore.com/products/panasonic-ncr18650b
Unless a 24v mono amp would be sufficient. In which case I'd just make a five cell 18650 holder.
Any advice on an amp/battery-voltage combo that would suit the above two woofer design?
What about, two of these, as a sealed, dual opposed woofer bipole design, run from a stepped up mono class-d amp. Would that need to be 2.4cf x2?
https://www.parts-express.com/Goldwood-GW-1258-12-Pro-Woofer-290-382
Perhaps I could run two of my 12v three 18650 battery holders in parallel to make sure I have enough amps for the stepped up mono.
https://www.18650batterystore.com/products/panasonic-ncr18650b
Unless a 24v mono amp would be sufficient. In which case I'd just make a five cell 18650 holder.
Any advice on an amp/battery-voltage combo that would suit the above two woofer design?
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Yes, and it won't produce much bass output.
Output is limited by "Hofmann's Iron Law": low, efficient, small, pick two.
Using sealed vs ported, you have lost 6dB low end efficiency- cover half the distance, or use four times the battery/amplification power to make up the difference. Picking a high Vas driver requires a bigger ported box.
For better output/size, look for a driver with a higher Fs and smaller Vas.
Since you are committed to low power amplifiers, the driver's excursion won't be an issue, so go for more (cheap)units, doubling the cone area gives you +3dB efficiency, equal to doubling battery/amplification power.
Then what about two of these, in a ported enclosure? Honestly, I'm feeling two drivers is about my max weight.