So, to make things more interesting, where does the 2 Ohm radio speaker rating come from?  I didn't search very hard but I didn't see it in the manual.  Based on the below, I would think they were actually 4 Ohm. 

The following is copied from:

 http://www.prestonelectronics.com/audio/Impedance.htm

So, how do you tell what the impedance of a speaker is?  On most cabinets, it should be printed on a label next to the jack.  If the speaker is visible, it may be printed on the speaker label or stamped on the frame or magnet. To measure the true impedance of a speaker or cabinet requires a rather complex procedure involving signal generators, power amplifiers and high frequency AC voltmeters.  However, with raw speakers and many cabinets,  the ohmmeter function of a digital multimeter can help you identify what the impedance of the speaker should be.  Generally, the reading given by an ohmmeter will be about 2/3  to 3/4 of the impedance of the speaker. So, a 4 ohm speaker will typically measure about 2.5 - 3 ohms, and an 8 ohm speaker will typically read about 5-6 ohms, while a 16 ohm speaker will measure around 12 ohms.

Good questions.? I have not been able to find any published specs on the radio's amp either.? I have pulled the radio and didn't notice any labels on it.

You are correct about getting an accurate measure of a speakers impedance.? When I measured the speakers that I pulled out of the Vision, I used a Fluke meter, but I know that is a crude/improper way to measure the speaker to address the following.

A speakers impedance rating is an "average" rating.? The speakers impedance can vary up and down with load and frequency.? Some speakers have more variance than others which will give lesser amps problems.? Electrostatic speakers tend to vary widely.

I am assuming the amp is more a 4Ohm amp than a 2Ohm amp because a 2Ohm amp would imply a better quality amp and I am skeptical that Victory put a lot of focus on the bike's amp quality instead of focusing their design dollars elsewhere.? I could be wrong.

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Thanks for the post. 

That pretty much settles the argument.  The OEM speakers are 4 Ohms, which means replacing them with 2 Ohm speakers will be stressing the existing amps.

Sincerely,

Tim

"...A 2 ohm speaker is way more efficient than a 4 ohm speaker...". 

You are considering only part of the equation.  You also have to look at the speaker's sensitivity rating.  This is at least as important as its impedance rating.

As a rule of thumb, a speaker that is 1/2 the impedance but is 3dB less sensitive will produce the same volume on a stable amp that doubles in power as the impedance load decreases. 

Examples using the same stable amp at the same volume setting:

• 2 Ohm Speaker @ 91dB will be as loud as a 4 Ohm Speaker @ 94dB.
  
• 2 Ohm Speaker @ 91dB will be as loud as a 8 Ohm speaker @ 97dB.
• 2 Ohm Speaker @ 91dB will be as loud as a 16 Ohm speaker @ 100dB.

"The original Vision speakers were 2 ohm..."

Are you saying Victory's speaker supplier changed speakers from late 2007 to present ?

Sincerely,

Tim

I already read that site.  It states 4 Ohms, but it doesn't show both late 2007 and current 2010 versions.

I got my Vision in late 2007.  When I measured the speakers, they were @ 3.5Ohms using a VOM.  I assume this link is for the current 2010 speakers.  If so, they probably were always @ 4 Ohms.

Thanks,

Tim

Any time you put a lower Ohm rating speaker on an amp, you make the amp work harder.  If the amp is not stable and was not meant to carry this load, you can burn up the amp.

The Vision's radio is reported to be 20watts x 2 channels.

Note, not all amps are created the same.  Some normally run warm/hot (Class A and A/B) and are not very efficient.  Others are much more efficient with more of the energy going into producing sound versus generating heat in the amps (e.g. digital switching amps, UCD amps, Class H and Class T amps).

I do not know the sensitivity rating of the Vision's speaker.  If you stay at 4 Ohms, you should be safe from the amp perspective.  If you find a more speaker with a TRUE higher sensitivity rating, it will produce more volume at the same volume setting on the radio.

Note 1:  Car speaker companies are notorious for publishing misleading specs.  I have tried a couple of car 5.25" speakers and all of them were less efficient than the factory speakers.  Good luck finding one that truly has higher sensitivity.

Note 2:  You need to consider the physical depth of the speaker.  The Vision speakers physically very shallow.  Car speakers with larger magnets will not fit into the Vision's fairing unless you remove the speaker shroud.

The best option I have seen to date is the J&M speaker replacements.  They give you more volume than the stock speakers.  They are shallow enough to fit within the existing speaker shrouds.  I have not heard of them burning up any of the Vision's radio amps and they have probably been out the longest.

I worked with a well known motorcycle speaker manufacturer in early 2008 and they would not recommend using their 2 Ohm speakers on the Vision's radio even though they wanted to enter into this market.

BTW, I just spoke with Biketronics today.  They will soon be coming out with a new 2 and 4 channel UCD (Universal Class D) amp that may fit the Vision.  They indicated the amp will be flat and very small, so I am watching their website for its formal announcement.

The J&M speakers are 1-way speakers (so they do not have woofers or tweeters). 

 http://www.jmcorp.com/SeeProducts.asp?PF=34

 They sound more clear than the factory speakers. 

Don't expect them to have heavy bass or bright top-end (due to the single driver).

If you do not have louder pipes on your bike they should be fine.  If you have loud pipes on your Vision, they will still be competing with the pipes.

I have not heard the Infinity Tweeters + the J&M's nor looked at the crossovers and resulting loads, but this might be your next option before resulting to a more expensive external amplifier solution.

Since the speakers are you 5.25", you will always be really low bass limited.

You can always by one pair and see how you like them.  If you like them, drop the other C-note.

They are louder and more clear than stock.  I would not say the are warmer (no more bass).

I started out with stock, then tried some car speakers (not as loud and didn't fit), then went to J&M, then went to an amplifier. 

Once you go to an amplifier, you have more issues to deal with.

Also, mobile audio follows the laws of diminishing returns.  Once you obtain sound, any additional money you throw at it, the less incremental improvements you get.

Tim

You might want to check with some other Vision owners in your area to listen to their rigs if they have done any mods before buying.  If I still lived in Wisconsin, I'd ride up to your area and let you listen to mine.

Tim