MEP-002A ASK Decibel Readings

[fireman5199]

There is always the question of "how noisy is it?" when talking about the MEPs. I have searched for actual decibel readings and haven't been able to find them so I took some myself.

My unit: MEP-002A with ASK on a M116A2 with cargo cover. It was running no load warmed up @ 60Hz 120V.

Decibel Meter: Smart Tools Sound Meter (ver 1.4.3) app on HTC EVO 3D

Readings:
Ambient 43 Db
Control Panel 107 Db
10' 93 Db
25' 86 Db
50' 77 Db
Aprox. 75' 68 Db

Personal evaluation: It is noisy at the control panel but doesnt cause pain but I would use hearing protection for sure if I was going to be there for more than a couple minutes. It seems to drop off drastically as you walk away. The low tone diesel is noise isn't that annoying. It doent seem as bad as lawnmower to me.

Disclaimer: I was using a phone app not a professional Db meter. I tried to make every effort to eliminate wind noise and handling interference. I am not sure if the meter pegged at 107 because it didn't move at all when at that level. Sorry if this is somewhere else on the site but I searched several ways and couldn't find it.

 

[Isaac-1]

I have measured my 3KW MEP-701a (1 cylinder Onan in ASK) before using a cheap import digital sound meter, but only at a couple of fairly close distances, there is too much stuff to block sound around where I have it (between 2 closely spaced sheds in my back yard) to get meaningful numbers at a distance. For a practical comparison though the reading was nearly identical at both distances to the reading from my old 4HP Sears push mower. To the ear the mower sounds a bit sharper, and the MEP sitting on concrete pavers pounds the ground hard enough for me to feel it through the soles of my shows over 20 feet away (it has a 600 CC vertical single cylinder engine running at 3600 rpms after all, that is awfully big for a one banger) .

Ike

 

[Speddmon]

If there is anybody out there with an MEP-002a WITHOUT the ASK, I would love for you to use the same app and measurements to find out how much of a difference the ASK makes!!!!!!!!!!!

 

[gimpyrobb]

I have a spread spectrum RTA with SPL meter on it. We could do "real" measurements on the mep003s at Kips if you remind me to bring it one of these days. It will show us not only what the DB is at a certain distance but also what frequency(hz) it is too.

 

[Speddmon]

I will certainly do that. I would love to be able to get some real and accurate readings to see the difference between ASK equipped gennys and non ASk ones. Mostly because I don't think the ASK makes that much of a difference

 

[derf]

If there is anybody out there with an MEP-002a WITHOUT the ASK, I would love for you to use the same app and measurements to find out how much of a difference the ASK makes!!!!!!!!!!!

I have a spread spectrum RTA with SPL meter on it. We could do "real" measurements on the mep003s at Kips if you remind me to bring it one of these days. It will show us not only what the DB is at a certain distance but also what frequency(hz) it is too.

To get valuable numbers you will need to do them in the same environment, with the same equipment, and from the same distances. Simple things like elevating the unit on 4x4s and having them on grass can make a huge difference. Also, sound measurement is very much relative. Conditions, calibration, frequencies, etc., can all have an effect on measured and/or perceived sound levels.
I have a couple of RTAs.
You can download TrueRTA free and play around with it. You'll need a mic although it will work with mics built into laptops. It is well worth the price (free).
True Audio: Audio Spectrum Analyzer and Loudspeaker Design Software
I use the TrueRTA when I don't feel like lugging my other RTA hardware around. It works OK. Side by side with expensive RTAs it can do the job pretty well.
Some things to consider:
To get real ASK vs. nonASK data you would have to test the same unit with and without the ASK.
"Noise" is somewhat more tolerable at lower frequencies than at higher frequencies sometimes.
Low frequencies, though, can propagate through concrete slabs and such. Sometime a little isolation (rubber pads, for example) can greatly reduce perceived noise.

 

[Harleyd315]

I had 2 MEP003 sets one with ask and one without. I had both set up in my driveway and took sound measurements with a good decibel meter. I'm no sound expert but the ASK only reduced noise by 10db. The ASK does make it a bit more tolerable but thats it. If I remember correctly 92 db vs 82 db.

 

[derf]

10dB can be a lot, especially if the difference is 82 vs. 92.
85dB is twice as loud as 83dB. The scale is logarithmic, I think.
+3dB is a doubling of sound. 90s are loud.
The ASK is also a weather shield, IMO. The 003 ASK that I have could stand some improvement, though. I think some good material applied to the inside of the panels could help a great deal.
The 701A ASK is a lot more substantial in construction than the 003 ASK that I have. The 003 ASK is like thin panels with some insulation on the inside where the 701A AS K panels are thicker and have a multi layer sandwich of sound deadening stuff on the inside.

 

[gimpyrobb]

To get valuable numbers you will need to do them in the same environment, with the same equipment, and from the same distances. Simple things like elevating the unit on 4x4s and having them on grass can make a huge difference. Also, sound measurement is very much relative. Conditions, calibration, frequencies, etc., can all have an effect on measured and/or perceived sound levels.
I have a couple of RTAs.
You can download TrueRTA free and play around with it. You'll need a mic although it will work with mics built into laptops. It is well worth the price (free).
True Audio: Audio Spectrum Analyzer and Loudspeaker Design Software
I use the TrueRTA when I don't feel like lugging my other RTA hardware around. It works OK. Side by side with expensive RTAs it can do the job pretty well.
Some things to consider:
To get real ASK vs. nonASK data you would have to test the same unit with and without the ASK.
"Noise" is somewhat more tolerable at lower frequencies than at higher frequencies sometimes.
Low frequencies, though, can propagate through concrete slabs and such. Sometime a little isolation (rubber pads, for example) can greatly reduce perceived noise.

Yup, I have been into audio for a long time. I know you need to measure with a "control". The frequency is why I mentioned using the RTA. Yes, 10db is a big reduction.

 

[Isaac-1]

Did anyone ever follow up on this?

Ike

 

[3dAngus]

10dB can be a lot, especially if the difference is 82 vs. 92.
85dB is twice as loud as 83dB. The scale is logarithmic, I think.
+3dB is a doubling of sound. 90s are loud.
The ASK is also a weather shield, IMO. The 003 ASK that I have could stand some improvement, though. I think some good material applied to the inside of the panels could help a great deal.
The 701A ASK is a lot more substantial in construction than the 003 ASK that I have. The 003 ASK is like thin panels with some insulation on the inside where the 701A AS K panels are thicker and have a multi layer sandwich of sound deadening stuff on the inside.

It would appear 85db is the "normally accepted" level for causing hearing loss. And 10 db is 10x's.
The transition from 92db to 82 db is significant and would protect the operator who would work close to the gen set.
I would wonder how effective it would be in helping one sleep.
82 remains extremely loud. You could probably get the same result in noise reduction from 20 feet by placing a sheet of plywood between you and the gen set. That is what I would love to see measured.
For $500 or more I would not be making an investment in an ask. 82 remains way to loud.
I would just find some good foam and plywood and allow the noise to rise upward.

 

[dependable]

If you have an ASK, it is worth it to add a muffler. Have a CUCV muffler on mine and it quiets it right down. Muffler not worth it as much without ASK, due to machine noise. Attached old pictures from previous posts.

 

[jamawieb]

In a military study I read sometime ago, test results from there stated 82db without ASK and 70db with the ASK. There is a noticeable noise reduction with the ASK units but not extreme.

 

[steelypip]

Probably worth mentioning that SPL measurements around equipment are usually done a particular way for industrial hygiene applications. The actual sensitivity is SPL of noise versus exposure time per day. So you can stand being around something quite loud for a short period without permanent injury, but exposure to something just a little too loud all day long day after day can result in permanent hearing loss. I seem to recall that A weighting at one meter is used for this purpose, but am not certain.