8 replies to this topic

[Johanmini]

the bike engine in my car makes quite some high frequency noises and nevertheless I really like those sounds I'm often afraid to damage my hearing. Till this point I used Alpine Motosafe universal earplugs. They come with two pairs of filters, with the highest level filter in it, it is bearable, but I noticed when I would put a headphone over it, this was ideal.

So now I ordered otoplastics, measured for my ear and earshell and told the manufacturer not to put in a filter at all. This provides the best silencer, I wasn't able to hear other roadusers anyway, so I'm curious if this is good for me!

I'm also curious what you guys are using and how this turns out for you.

[cptkirk]

No ear plugs for me, the Dynamat sound deadening works a treat, yes the cars heavier but I wanted some luxury.

I know it really didnt answer your question but I thought I'd put it out there.....

If with my new setup I might get a lot more whine from the charger now it'll be spinning 2000rpm faster + a more open air filter, so I might need to invest, I am interested to see what others are using also....

[MaxAndPaddy]

Yet another TMF problem solved....on to my next

[Johanmini]

No ear plugs for me, the Dynamat sound deadening works a treat, yes the cars heavier but I wanted some luxury.

I know it really didnt answer your question but I thought I'd put it out there.....

If with my new setup I might get a lot more whine from the charger now it'll be spinning 2000rpm faster + a more open air filter, so I might need to invest, I am interested to see what others are using also....

actually you did help me...I used some kind of aerospace stuff in order to get it some bits cooler, I used it on the board between engine and cabine and on the back of my seat, it still gets pretty hot through the shifting part. The noise didn't really noticable change. where did you use it and do you have any pictures of the look of it? Did also cool the cabine down?
I really don't care much about the weight, I don't by far use all of my horses available, so I have some spare to throw at it when I get bored.

[cptkirk]

I used dynamat all over the car, but mostly I used it on the rear firewall/vertical bulkhead and parcel shelf. It even came in handy as a seal when fitting the bulkheads, you can see it here: http://www.theminifo...ost__p__1458272

My recommendation is to order it from the USA as it's that much cheaper you can pay import tax and still save a truck load of cash, that is unless you have a cheap source locally. I think all in I only added around 20kgs of sound deadening (thats a wet finger in the air guesstimate - it was two big packs of dynamat).

As for heat, its hard to say as my exhaust is on the rear of the engine, I can say that after about a half hour of regular driving you can feel a radiant heat in the back of the seats, but I expect the temps in the engine bay to be up in the +100degC so its not doing to bad, I have mine carpeted also so this might help a little.

[clovus]

Interesting topic.

As a general rule a safe level depends on the level of the noise, the length of time you are exposed to the noise, and other factors such as medications and genetic factors. Noise damage is cumulative so limiting exposure and giving your ears a rest is important.

91dB is considered safe for up to 2hrs, as the intensity (loudness) goes up the acceptable duration decreases. At 100db it is around 15 minutes. The dB measurement at the exhaust is not accurate for hearing safety, it is more for ambient noise pollution. Besides, the cabin of the car acts like a speaker cabinet, and introduces resonances. In combination with vibrating panels the interior may be much louder. Even though they are not totally accurate, you can download some sound level meters iPhone apps that will give you an idea. Hold it close to you will give an indication.

A custom set of earplugs is the best protection. They need to be a firm fit, even a 1mm gap can render them ineffective for very high frequency noise. In addition, they need to go into the ear canal quite a long way to give the most effective protection. If you are using the foam roll up type, such as the ear25 yellow plugs you need to insert them so there is no part sticking out past the canal entrance. Due to the physiology and acoustic characteristics of the cochlea (the inner ear), even different sound frequencies can damage the ear, usually at 4kHz, although I have seen damage at 3 kHz with aircraft service personnel.

[clovus]

Forgot to add, I am a Audiologist so have more then a passing interest in this.

Best possible protection would be ear plugs and a helmet. If the sound is loud enough and includes very low frequencies, even ear plugs will not be sufficient and the head needs shielding for best protection.

Of course I am open to being given a Z Car conversion to investigate this further.....Purely for scientific reasons......


Thanks for reading!

[Johanmini]

Interesting topic.

As a general rule a safe level depends on the level of the noise, the length of time you are exposed to the noise, and other factors such as medications and genetic factors. Noise damage is cumulative so limiting exposure and giving your ears a rest is important.

91dB is considered safe for up to 2hrs, as the intensity (loudness) goes up the acceptable duration decreases. At 100db it is around 15 minutes. The dB measurement at the exhaust is not accurate for hearing safety, it is more for ambient noise pollution. Besides, the cabin of the car acts like a speaker cabinet, and introduces resonances. In combination with vibrating panels the interior may be much louder. Even though they are not totally accurate, you can download some sound level meters iPhone apps that will give you an idea. Hold it close to you will give an indication.

A custom set of earplugs is the best protection. They need to be a firm fit, even a 1mm gap can render them ineffective for very high frequency noise. In addition, they need to go into the ear canal quite a long way to give the most effective protection. If you are using the foam roll up type, such as the ear25 yellow plugs you need to insert them so there is no part sticking out past the canal entrance. Due to the physiology and acoustic characteristics of the cochlea (the inner ear), even different sound frequencies can damage the ear, usually at 4kHz, although I have seen damage at 3 kHz with aircraft service personnel.

the hack did delete my latest reaction.

I ordered custom plugs called otoplastics with an earsell filling shape, normally they stop a bit earlier, but I wanted max protection. I requested not to ad a filter to the plugs, this deletes communication...but I wasn't able to communicate in the first place so now I choose to protect my ears maximal. I tried the iPhone app, but they only go untill 96db....it doesn't come lower in my car at all, only at static. So these plugs come in handy :)
i was wearing the Alpine motosafe ones which are universal fit and don't go in very far, they filter good, but not enough to my taste.

It is a quite nice sound, and some of my buddies who I take along for a drive tend to not wear plugs or other earprotection because they don't think the noise is too loud, but I know it is and I only take guests when they agree to wear the pinky's as posted above or a helmet.

it's what you say, it doesn't seem so loud and damaging as it is in reality through the resonation. I noticed this when my ears where hurting after a longer run and I really like my ears and what they do :)

Edited by Johanmini, 25 April 2012 - 09:12 AM.

[invisible_kid]

I know that aircraft personal in the navy hav head sets that block all noise completely. These also hav special microphones that block out all the bad frequencys so they can then have a normal conversation with each other without all the background noise from gun batteries etc. I Dnt kno much bout them bt my lecturer at college was tlking bout them in my acoustic class. This was a few years ago now mind u and they are ridiculously expensive lol