I installed some BT7.1's, a BT2180 and a Kenwood X998 a couple of months ago. I installed a liberal amount of polyfill sheets over the 7.1's and thought everything sounded great. Today, I was doing a few tweeks to the bike that required taking the fairing off and decided to unwrap the polyfill off the speakers. Instead, I took some new sheets of polyfill, cut it to fit and lined the inside of the fairing with 4 layers with a few shots of spray adhesive. 4 layers was just the right thickness to make it snug.

I can't believe how much that improved the sound!!!! By treating the inner fairing it greatly reduced a lot of resonating noise I was getting. I used to have a really nice 2-channel audio system in a dedicated room that I acoustically treated with panels I made with Owens 703 rigid fiberglass acoustic panels. I bet that would do an even better job.

Anyone else lined the inner fairing and had good results?

 

I have my bags and inner fairing lined with dynamat or similar brand I found on eBay for a small cost, figured for 25.00 it was worth a try. I didn't line the entire fairing only the portion behind the speakers and then 2 thin sheets of polyfill over the speakers.

I have a good amount of bass coming from my fairing now

 

Now don't laugh. But believe it not I have JM Johns inner fairing liner and it works dam good! There are quite a few things the ole' boy did right.

 

I lined a Dragonfly fairing with Dynamat in past and thought it did tighten up sound. On my current bike I put some Dynamat Dynaxorb panels behind the speakers. One of old audio icons on here Firecap501 said mouse pads clued behind each speaker did same thing. More recently added some polyfil to fairing speakers.

 

seems there is a little confusion when it comes to sound changing products so let me help and shed a little light. this is mostly written from a car audio point of view but the ideas are the same.

CLD - constrained layer damper - most commonly known brand is dynamat. this is the first step in helping remove vibrations. typically 25-40% coverage on large, flat areas of metal panels is all that is needed. the better (modern) stuff is made from butyl and has a layer of aluminum on top. the butyl converts vibrations into low-level heat which is then dissipated by the aluminum. contrary to popular belief you do not need to layer this stuff on. anything more than 40% coverage on flat panels is wasting time, product and money.

CCF - closed cell foam - various companies make this stuff. it's main function is to be a decoupler between CLD and MLV. it can absorb some of the higher end frequencies as well. a lot of people use yoga mats for this layer as they are cheap and easy to obtain. this should be applied in 100% coverage with seams taped closed.

MLV - mass loaded vinyl - again, may companies make this. this is the only material that actually blocks/stops sound. a quality MLV should weight around 1lb/sqft, needs 100% coverage and seams taped well (sound like water will look for the path of least resistance). while some choose to apply this with a spray glue i prefer to use velcro as it makes for easier application, cleaner application and you can remove and reuse it later if you so desire.

polyfill - you can pick this up at any craft store or even walmart (look in the sewing area, most commonly used as pillow stuffing). this is placed inside speaker enclosures when you do not have the airspace needed for the specs of the speaker, and most commonly used with subs. the polyfil will slow down the sound waves, tricking the sub into thinking it has more airspace.

those are the basics. people use different products in different ways with mixed results, but to each his own. some people go to home depot and buy roofing material instead of a true cld (please don't do this). all that matters in the end is what your ears think of your gear. if anyone has any questions, or wants to know more, feel free to drop me a pm. i have ran the gauntlet from piling on 3-5 layers of a cld (when i didn't know any better) to full installs of all products mentioned including spray foam for this like a-pillars and trunk lids.

 

Has anyone tried to install the foam speaker cups on their speakers? Something like below.

http://smile.amazon.com/DEI-050330-R...5%3A2470955011

I have installed this in several vehicles and could tell a huge difference.

 

Did they improve resonating noise or bass response? Wonder if the make any for the BT7.1's?

 

You don’t want those on a bike. Remember in a car lower power will sound find because you are in an enclosed space. On our bikes we are pumping the hell out of the speakers and they need air to move, hence, why BT sells a bracket to eliminate the pods the 14-15’s come with. You don’t want to make the enclosure even smaller restricting air flow. Polyfill is meant for the speaker to feel as if it’s in a bigger enclosure, add some dynamat and your golden.

 

Just added the Dynamat type material on each area behind the speakers. I covered from the vertical rib over to the left, then the same on the right. Coverage looks like about 40-45% of the total surface area. I had a few rolls I was going to use on another vehicle but decided to use a little. Put it all back together and I can tell a difference. My amp is removed so I can't compare until my new Cerwin Vega B2 arrives. It's on its way so that will be the moment of truth.