Decibel levels question

[11kolive]

My wife and I are driving to the Seattle area today talking about the A25 we use to own and wondered if anyone had any decibel readings while underway from various parts of an A27 and A25 to compare. It sounded like a like a nice bit of data to easily acquire and share. We have a decibel app called Decibel 10th that I use frequently on board and when playing music. It would be great to set it up so data would be as consistent as possible. Such as; Engine type, rpms, location of meter for acquisition of info, aft cabin-helm-cockpit bench and v-berth area. Putting it into excel and sharing in the documents location would make it easily available for folks too. Different rpm settings would show some very useful info for owners and prospective owners too.

Our A25 was very reasonable and db levels never interfered with conversation or naps.

If anyone feels like it, check out the app and see what you think. I would be happy to collect any data and put it into excel to share. Photos of collection locations might help standardize the collection.

Sorry for the long winded post, it was a 3 1/2 hr drive to our boat and we brainstormed a lot. Our current boat is a Grand Banks and we are working towards downsizing to an A27.

[Beta Don]

. . . . wondered if anyone had any decibel readings while underway from various parts of an A27 and A25 to compare. It sounded like a like a nice bit of data to easily acquire and share. We have a decibel app called Decibel 10th that I use frequently on board and when playing music. It would be great to set it up so data would be as consistent as possible. Such as; Engine type, rpms, location of meter for acquisition of info, aft cabin-helm-cockpit bench and v-berth area.

Golly, you just listed half a dozen of the variables which would make meaningful comparisons nearly impossible - Add in different models of phones, exactly which direction the phone was pointed, how many people and other 'stuff' were aboard soaking up some of the reflected sounds. "Data to easily acquire and share . . . . as consistent as possible" . . . . seems almost impossible to me to get any meaningful info, let alone something you could actually use for A to B comparisons

Don

[11kolive]

Don, we thought some of the same thing but figured we'd ask the question to see what there thought. We had not thought of the different phone issue and some of your other points, so maybe it is not a viable idea. I will see about retracting the question and let it go. Thanks for the reply and your thoughts.

[DougSea]

I still found the original post interesting, even if there are challenges in getting good data for a "scientific" comparison.

AND I downloaded the app and will be trying it out on our 35. It appears there's some form of calibration that can be done that would level out the results. Where it will be interesting for me isn't so much in comparing to others, but in seeing what I can do on my boat. For example - Bimini up vs. down on the flybridge. Not the sort of thing you can do while listening. I THINK it's quieter with it down. But don't really know. Now I will!

[Beta Don]

I think something like that would be very useful as a guide for making noise reduction changes to a particular boat - If you think you have an idea which might make it quieter, give it a trial test before you spend a lot of time/money on something more permanent which may not do much to resolve the problem. I'm just not sold on the idea that using it to create a database for comparing noise readings on similar, but different 30+ year old boats would result in valid data

It would have been very interesting to compare noise levels on Vic's boat before and after his noise reduction blanket was installed. I understand that made a major change in the noise level and quantifying that would be really helpful

Don

[Vic K]

FYI:

Between the new engine mounts and the sound blanket there was a big difference in sound 'quality' of the 4D61 in Mary Jo. Several people that had heard the 'before sound' commented about the difference in the'after sound'. One thing I noticed above all was that the engine sound dropped in pitch. The tone was lower and much easier on the ears. I might add more pleasant. I'm sure lowering the vibration via the engine mounts had a lot to do with this. These mounts came off a new Beta 50hp. Mary Jo had very little sound insulation. I did replace the sound proofing in the engine covers but that was about it.

Vic

[Bearkeley]

It would have been very interesting to compare noise levels on Vic's boat before and after his noise reduction blanket was installed. I understand that made a major change in the noise level and quantifying that would be really helpful

Don

Happy to try it with and without the blankets and let you know the results....you ready to come visit, CaptnVic? The blankets definitely make a difference but we'll put a little science behind it!