Replies to This Discussion

Permalink Reply by Todd Allen on May 2, 2011 at 1:40am

How many channels is your amp?  2? 4?  Is the 120 watt rating per channel or is it total power out?  Is it RMS or a peuak rating?  Does it have an adjustable gain?  If so you can dial it back to avoid blowing low power speakers.  A reasonable procedure would be to dial the gain to minimum, connect your speakers and your sound source.  Play the loudest/harshest piece of music you are likely to ever play and gradually dial up the source volume to max or just shy of it.  With the gain down on the amp the output should still be modest.  Then slowly bring up the gain and stop as soon as you hear any distortion.  This should keep your speakers reasonably safe.

 

Anyway, the 10 watt speakers pictured probably won't cut it.   The 20 watt may not either depending on how hard you expect to push them. Impossible for any one else to say what speakers you'll find good enough as it is a very subjective thing.

Permalink Reply by Matt on May 2, 2011 at 11:18am

This was indeed my worry. The speakers don't appear to come apart easily either, the rear panel is glued on hard and the speakers don't appear to be removable from the front. I would have to destroy the casings to open them up.

 

To answer Todd's questions, my plan was to mount one amp and a set of two speakers on both the front and back ends of my bike. The amp I have now is two-channel and I believe it does have an adjustable gain control, but I am not even sure yet whether it can be made functional. I will bear your suggestion in mind for when the time comes, though.

 

So I have to start from scratch. I am sure there are many variables to consider. Should I visit a car stereo store? Read an article online? Purchase the midrange speakers H3 suggests and go from there? Where does one start?

Permalink Reply by Matt on May 3, 2011 at 8:39am

I don't see any way to do that. They appear to be nailed in from the inside.

 

Permalink Reply by Matt on May 5, 2011 at 8:19am

Have you ever looked at weather resistant speakers like these? They look powerful, but I don't know what the casings are made of and whether they could withstand the turbulence of bike travel.

 

http://www.amazon.com/gp/product/B002BLWX2E/

Permalink Reply by Todd Allen on May 5, 2011 at 3:42pm

I'd hook up what you have now and see how it works.  If you like it, then it could be worth the effort to mount them or deconstruct the boxes and remount/rehouse the drivers for use on your bike.

 

I've used both indoor and outdoor speakers on my bike trailer.  Indoor speakers can work ok on a bike if you can shelter them somewhat or avoid foul weather.  Avoid paper cones and porous surrounds and you should do pretty well.

 

The peace of mind from all weather or marine speakers is nice, but it often comes at significant price or a hit in  performance.  Try to listen to speakers before you buy them.  It's pretty much impossible to compare speakers by specs, especially considering most are listed with rather incomplete specs that are often fudged.  If you can't find them locally to listen to, at least hunt out reviews on the net.

 

One set of specs you can compare are weight and dimensions.  Make sure you don't get speakers that are too big or heavy for your purposes.  If you aren't sure what your limits are, find or make something similar in size and weight and strap it on and go for a test ride.

Permalink Reply by Matt on May 6, 2011 at 11:45am

Before posting this thread, I tried the smaller set of speakers out by attaching them to a boom box. I was alarmed by the weak sound -- weaker than the boom box would do on its own, and that is far from adequate. On the other hand, I thought attaching them to a boom box might in itself be giving the power a hit. So I posted here.

 

I had attached the larger pair to my home stereo system, but I was concerned that the acoustics in my basement were helping boost the sound. 

 

I will see if I can replace the fuse for my amp this weekend. 

 

Last weekend I strapped the speakers on to my bike using bungee and took it for a brief spin. While I would not ever, ever consider such a set up for a real ride, it did serve to confirm they would not be too heavy, nor would they impede my ability to ride or interfere with the workings of the bicycle. 

 

Permalink Reply by Todd Allen on May 6, 2011 at 3:34pm

>On the other hand, I thought attaching them to a boom box might in itself be giving the power a hit.

 

 It might be an impedance mismatch.  For example if the boom box speakers are 4 ohm and your test speakers are 8 ohm you are likely to get a significantly reduced max volume.  If the mismatch goes the other way you can get excessive volume, distortion and risk blowing the speakers or the amp.  If you buy a separate amp it will likely support an impedance range, say 2 to 8 ohm for car stereo or perhaps 8 to 16 ohms for a PA type amp.  But for a boom box a manufacturer may save a couple bucks by using a less flexible amp.

Permalink Reply by Matt on May 7, 2011 at 11:35am

My amp is receiving power per my multimeter, and the fuse has been replaced, but it appears to be dead. :(

Permalink Reply by Matt on May 10, 2011 at 8:13am

I finally hooked my speakers up to my home stereo again and tried testing them for high volume. Once I heard distortion, I dialed the sound down as Todd suggested, then played with the volume a bit more and checked to make sure the cones were vibrating. Turns out I must have pushed them a bit too far, as only one of the four speakers survived the test. :(

 

For what it's worth, they were free, given to me by someone who had no further use for them. I really don't think they had what it would have taken to fill up even a small section of street.

 

I might like to try deconstructing the boxes and replacing the drivers someday, but at the moment this is something I have no idea of how to do without destroying the wood. My goal at the moment is to have something for the May mass.

 

Back to the drawing board ...