Looking for ways to do exactly the opposite of what my skill set has taught me. I'm used to building big, loud subs with inefficient drivers in sealed enclosures and lots of wattage. I'm considering doing the opposite; inexpensive, efficient driver for modest output. Long story short, I have a motorcycle with two 6.5" coax in the fairing and they do a poor job of reproducing flat. From about 300hz up they are wonderful. I just want to fill in the lower stuff. I don't need to boom boom, just want to get a little more SPL down to a decent cutoff... maybe 60hz?
I might have space for an 8" in one of the hard bags, but I have a feeling one or two 6.5" subs would be a better fit. How do I engineer an enclosure to maximize their potential? I have about 60w RMS to play with, and only stable to 4ohms.
I might have space for an 8" in one of the hard bags, but I have a feeling one or two 6.5" subs would be a better fit. How do I engineer an enclosure to maximize their potential? I have about 60w RMS to play with, and only stable to 4ohms.
An efficient speaker from 300Hz to 60Hz?
The Boominator - another stab at the ultimate party machine
But it doesn't go down to 60Hz.
The Boominator - another stab at the ultimate party machine
But it doesn't go down to 60Hz.
As much as I like the idea of a Boominator on a motorcycle, I think a better question would be how much space in one of those hard bags and what dimensions will fit in there?
Johan
Johan
There are 3 properties that cannot all be optimized together, efficiency, bass extension and enclosure compactness. If you want efficient, low bass, you need a _big_ enclosure.
i've tried and lost on motorcycle installs...two big problems "road and engine noise" and "helmets"
the best i've managed was a horn with a 120 hz cutoff mounted in a front faring/cowl and lows fed to a "throne thumper"
the best i've managed was a horn with a 120 hz cutoff mounted in a front faring/cowl and lows fed to a "throne thumper"
I haven't measured the hard bag, but just eyeballing it I'm guessing a little more than .75 cuft.
No helmet to contend with except on highways... at which point the road noise drowns out everything so who cares. Even so, I wear a brain bucket so my ears are exposed. I'm looking more for the lazy sunday back-road thrashes.
As far as the shape of the bags, this won't be a "build a cube and call it good" thing, I'll have to frame something up out of something flexible like luan and make a fiberglass enclosure. The fabrication part is my strong point. I can build anything, just need to know how to go about building it.
Most of my experience is going with factory suggested volumes... that is to say, the factory says "sealed enclosure 0.8-1.25 cu ft"... so I build a 1.25 cu ft mdf box and EQ it from there. I rarely do ported or bandpass (mostly because I like my trunk to actually have cargo room) and even when I do some kind of porting, I just follow instructions.
And I was exaggerating a bit on the 300hz. The speakers are advertised as 40-22k hz, but they don't list a -3db point. So let's be optimistic and say they are reaching down to 150 effectively, but they drop off pretty quickly... at least what my ear is telling me.
They are Polk dB 652 speakers, in case that helps.
No helmet to contend with except on highways... at which point the road noise drowns out everything so who cares. Even so, I wear a brain bucket so my ears are exposed. I'm looking more for the lazy sunday back-road thrashes.
As far as the shape of the bags, this won't be a "build a cube and call it good" thing, I'll have to frame something up out of something flexible like luan and make a fiberglass enclosure. The fabrication part is my strong point. I can build anything, just need to know how to go about building it.
Most of my experience is going with factory suggested volumes... that is to say, the factory says "sealed enclosure 0.8-1.25 cu ft"... so I build a 1.25 cu ft mdf box and EQ it from there. I rarely do ported or bandpass (mostly because I like my trunk to actually have cargo room) and even when I do some kind of porting, I just follow instructions.
And I was exaggerating a bit on the 300hz. The speakers are advertised as 40-22k hz, but they don't list a -3db point. So let's be optimistic and say they are reaching down to 150 effectively, but they drop off pretty quickly... at least what my ear is telling me.
They are Polk dB 652 speakers, in case that helps.
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Hi curtis73,All
Polk dB 652 is down -3dB at ~75 Hz
https://d3vqw2nv1topde.cloudfront.net/assets/Product Documents/DB Plus Series Manual.pdf
Here is a 10 Year old idea:
b🙂
Polk dB 652 is down -3dB at ~75 Hz
https://d3vqw2nv1topde.cloudfront.net/assets/Product Documents/DB Plus Series Manual.pdf
Here is a 10 Year old idea:
b🙂
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You could go with a simple sealed or ported enclosure, if the driver is of sufficient size, I would look at an 8" or 10". If you mount the driver in the side of the bag, with a grill and some acoustic foam in front, you might actually have some storage space left. Other options are 4th or 6th order band pass for a bit more output in a smaller bandwidth (say 50 - 150 Hz).
Regards
Regards
Kicker has ( or previously had ) a Harley demo bike at HQ in Stillwater, OK with bandpass enclosures built into the stock side bags. The port output was IIRC 2" or 3" diameter and was facing the frame, just barely visible. The upper lid area was sealed off and had what appeared to be Aura wideband drivers, facing upwards.
I checked their 'vehicles' list, but it is not on there. The Chevy Cruise was in the facility when I was there prior.
KICKER Vehicles
I checked their 'vehicles' list, but it is not on there. The Chevy Cruise was in the facility when I was there prior.
KICKER Vehicles
I'm leaning toward bandpass simply for the SPL it can do with lower wattages. Just not sure I can get enough volume with an 8", and not sure one or two 6.5" will really do much.
I was playing with a calculator. Does this seem right to you? 0.09cuft front and 0.123cuft in the back? Seems awfully small. The driver here is a Dayton 6.5" sub.
I was playing with a calculator. Does this seem right to you? 0.09cuft front and 0.123cuft in the back? Seems awfully small. The driver here is a Dayton 6.5" sub.
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I am often entering this thread, only to realize once again that it is a subwoofer for .......motorcycle ! ?.....
Could someone correct the title ? 🙁
Could someone correct the title ? 🙁
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I certainly don't mind changing the title, but I don't see how it changes the content of the thread. The same principles apply regardless of boat, house, car, or anything else.
In the motorcycle there is no room gain, and to be frank, I do not think that pretending to hear "sub frequencies" in it is justified, taking into account the environmental noise, the use of the helmet, etc. etc .
But I know what this thread is about, thanks for the reply, friend. 🙂
Thanks for your opinion. It is done all the time with much success, albeit usually with a bit more wattage than I have room for.
And no helmet.
This is not so I can hear massive bass on the highway, this is to fill in lower frequencies on 35 mph backroads cruising.
And no helmet.
This is not so I can hear massive bass on the highway, this is to fill in lower frequencies on 35 mph backroads cruising.
It looks decent and might be enough. One thing: The port has a 4" diameter and is 60" long, so your port alone is over half a cuft.
Either increase the chamber size, or decrease the port diameter (or both). A single 2 - 3" port should be enough.
Johan
Either increase the chamber size, or decrease the port diameter (or both). A single 2 - 3" port should be enough.
Johan
Good to know. I can do a 2" but I was concerned about port noise.... then remembered... this is on a motorcycle. I don't care about port noise.
So you're going to break the law by driving without a helmet? That is dangerous, take care please
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Some states do not require motorcyclists to wear helmets. Laws vary in many jurisdictions.
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