[Littlebear]

Hello BMW Experts!
I'm thinking of putting a fancy exhaust onto my 2017 330i. Since I won't feel the HP gain, my other criteria are weight, which differs only a little bit, and sound!
I only have found one site that rates exhausts for sound volume:

https://www.carid.com/2017-bmw-3-ser...er=1&sub-model[ourBodyTypeName][]=Sedan

But they only have two levels, moderate & aggressive/loud. I would like a better than stock, but not much louder. This leave two at that site, the Magnaflow Touring & the AWE Touring.
Can anyone give a ranking of the loudness of different exhausts, or offer an informed opinion of such, pls?

TIA! Murf

[rjd_F30]

We made a small ranking (still ongoing if people continue to make entries) regarding this exact topic and measuring N20/N26 exhaust setup decibel levels. Here is the thread: https://f30.bimmerpost.com/forums/sh....php?t=1543943

I know that is talking about the N20/N26 and not the B48, but I think the results would be similar.

That aside, from what I know about and my experience with the MPE, it sounds like it would suit your needs well. When I ran it as my sole exhaust modification on my 328i it was pretty mild as far as volume but dramatically improved the actual sound of the exhaust note. Judging by what you said about what you'd like, I think the MPE should be the first place you look.

[Littlebear]

Hi rjdnyy224,
Thanks, that is an interesting read. I imagine there are a few probs with consistency between cars, instruments, & environment. I wonder how cruising decibels could be estimated by these measurements.
I guess the MPE is the most mild loudness upgrade. The 335i muffler is a quiet cruiser, but is that a quad tip which would need rear valence cutting?. If anyone can comment on some Magnaflows, that would be cool.

TIA! Murf

[rjd_F30]

Originally Posted by Littlebear

Hi rjdnyy224,
Thanks, that is an interesting read. I imagine there are a few probs with consistency between cars, instruments, & environment. I wonder how cruising decibels could be estimated by these measurements.
I guess the MPE is the most mild loudness upgrade. The 335i muffler is a quiet cruiser, but is that a quad tip which would need rear valence cutting?. If anyone can comment on some Magnaflows, that would be cool.

TIA! Murf

Yah it's not the most precise, but it no doubt at least gives you an idea for what is listed . And while I haven't heard many F30 exhausts in person I would venture a guess that the MPE is one of the quieter options, with Dinan undoubtedly being the quietest.

And yah a 335i muffler would require some sort of modification to the rear valence to accommodate the dual outlet.

[RMachuca3d]

I have the MPE and it is indeed quite quiet, I’d say around 10-15% louder than stock tops, thinkingnof putting back on my muffler delete.

[Littlebear]

[QUOTE=rjdnyy224;23938600... I would venture a guess that the MPE is one of the quieter options, with Dinan undoubtedly being the quietest.
[/QUOTE]

From reading here, opinion on volume seems to be MPE, Dinan, mild, then AWE being quite loud. But the linked Carid page has Dinan being noisy, with AWE & Magnaflow "Touring" being less loud.

Murf

[rjd_F30]

Originally Posted by RMachuca3d

I have the MPE and it is indeed quite quiet, I’d say around 10-15% louder than stock tops, thinkingnof putting back on my muffler delete.

We actually did the math in the above thread using decibel testing. The MPE is exactly 57% louder than stock when revved.

Originally Posted by Littlebear

From reading here, opinion on volume seems to be MPE, Dinan, mild, then AWE being quite loud. But the linked Carid page has Dinan being noisy, with AWE & Magnaflow "Touring" being less loud.

Murf

In short, CARid is wrong lol. Dinan makes by far and away the quietest aftermarket exhausts for BMW. They provide an excellent tone but a very, very minimal increase in volume. The MPE is markedly louder than stock (57% increase in volume; mentioned above), and yields a nice improvement in sound quality. I don't know about magnaflow, but AWE makes some pretty loud systems. Their "mufflers" are closer to a straight pipe than a muffler, explained well by Noelified here: https://f30.bimmerpost.com/forums/sh...5&postcount=21

[Billfitz]

Originally Posted by Littlebear

I imagine there are a few probs with consistency between cars, instruments, & environment. I wonder how cruising decibels could be estimated by these measurements.

It's far more involved than that, based on the pitch of the sound. We don't hear all frequencies as equally loud. Far from it. You can have a low frequency tone, say 100Hz, and a midrange tone, say 1000Hz, measure exactly the same, but the 1000Hz tone will be heard as being as much as four times as loud as the 100Hz tone. That being the case there's no quick and easy method of comparing exhaust tone or perceived loudness via a simple SPL measurement alone.

[rjd_F30]

Originally Posted by Billfitz

It's far more involved than that, based on the pitch of the sound. We don't hear all frequencies as equally loud. Far from it. You can have a low frequency tone, say 100Hz, and a midrange tone, say 1000Hz, measure exactly the same, but the 1000Hz tone will be heard as being as much as four times as loud as the 100Hz tone. That being the case there's no quick and easy method of comparing exhaust tone or perceived loudness via a simple SPL measurement alone.

Understood, but isn't it safe to assume that the frequency of the sounds being measured will be roughly the same? Considering it's the same engine across the board, I would imagine the exhaust note, regardless of exhaust setup, would be similar, rendering that confounder largely immaterial.

[Sweeney921]

I have Supersprint's dual-tip catback exhaust with resonated mid-pipe on my B46. It's probably 20% or so louder than stock with subtle burble on upshifts and over-run. I'm glad I got the resonated mid-pipe because there's absolutely zero drone. Also looks great.

Overall happy with it despite the price and custom fabrication needed to make it fit up to the OEM B46 downpipe. Supersprint designed their mid-pipe for the B48, which has a different connection between the downpipe and mid-pipe than the B46.

[Billfitz]

Originally Posted by rjdnyy224

Understood, but isn't it safe to assume that the frequency of the sounds being measured will be roughly the same?.

It's not. Most mufflers are Helmholtz resonators. That means they can be tuned to reduce specific frequencies more than others. You can have ten different mufflers tuned to ten different frequencies, with ten very different sound characteristics. That means you can also have ten different exhausts that all measure the same average SPL but are heard at ten different volumes. Or you can have ten exhausts that sound the same level but measure at ten different levels. This is why most noise statutes are doomed to failure. The level of expertise and gear required to successfully enforce them are way beyond what not only the average cop has at his disposal but also the average inspection station.

[rjd_F30]

Originally Posted by Billfitz

It's not. Most mufflers are Helmholtz resonators. That means they can be tuned to reduce specific frequencies more than others. You can have ten different mufflers tuned to ten different frequencies, with ten very different sound characteristics. That means you can also have ten different exhausts that all measure the same average SPL but are heard at ten different volumes. Or you can have ten exhausts that sound the same level but measure at ten different levels. This is why most noise statutes are doomed to failure. The level of expertise and gear required to successfully enforce them are way beyond what not only the average cop has at his disposal but also the average inspection station.

So barring the use of ultra high-grade professional equipment, all attempts at SPL measurement are futile? I would agree that most provide only rough estimates, but that's really all I'm looking for.

Also, because frequency affects only our perception of how loud something is and not it's actual SPL, I would still consider decibel testing to be objective. Some things with different frequencies may sound slightly louder or quieter than others even if they register the same SPL, but it will at least give us a rough estimate. If that weren't true the decibel scale would be completely moot.

[Billfitz]

It's not moot, but it's far from perfect. It was literally invented by Bell Telephone to measure the volume losses incurred over long telephone lines, so they would know how far apart they had to place volume boosting repeater stations. They never considered the effect of equal loudness, as all they cared about was the limited frequency band width of telephone transmission. Equal loudness studies came along much later, in 1933, after the advent of movie sound. If the decibel scale and the methods of measuring sound levels had been invented by RCA or Western Electric instead of Bell Telephone it would probably be very different, but it's way too late to turn the clock back now.

[rjd_F30]

Originally Posted by Billfitz

It's not moot, but it's far from perfect. It was literally invented by Bell Telephone to measure the volume losses incurred over long telephone lines, so they would know how far apart they had to place volume boosting repeater stations. They never considered the effect of equal loudness, as all they cared about was the limited frequency band width of telephone transmission. Equal loudness studies came along much later, in 1933, after the advent of movie sound. If the decibel scale and the methods of measuring sound levels had been invented by RCA or Western Electric instead of Bell Telephone it would probably be very different, but it's way too late to turn the clock back now.

So then I think we can agree at least a little bit. I agree that it's not perfect, but it's a better comparison than no comparison at all.

[Noelified]

Originally Posted by rjdnyy224

So then I think we can agree at least a little bit. I agree that it's not perfect, but it's a better comparison than no comparison at all.

In a couple weeks I'm hopefully going to a car&coffee grand opening of a car detailing and storage facility. I know of two locals that may be going as well. S3RIES28 paimon.soror Maybe if all three of us are able to make it, and have participated in our decibel thread, we can compare data results to our in person perception of volume. Three people comparing three sets of data and then listening to all three cars should give us some idea if the numbers are accurate enough for our purpose....or not. How far are you from Portland, CT

[rjd_F30]

Originally Posted by Noelified

In a couple weeks I'm hopefully going to a car&coffee grand opening of a car detailing and storage facility. I know of two locals that may be going as well. S3RIES28 paimon.soror Maybe if all three of us are able to make it, and have participated in our decibel thread, we can compare data results to our in person perception of volume. Three people comparing three sets of data and then listening to all three cars should give us some idea if the numbers are accurate enough for our purpose....or not. How far are you from Portland, CT

That'll be really interesting to hear the in person impressions vs. the data we got. What is the exact date of the meet? I could probably make it to Portland depending on if I'll be home from school or not.

[Noelified]

Originally Posted by rjdnyy224

That'll be really interesting to hear the in person impressions vs. the data we got. What is the exact date of the meet? I could probably make it to Portland depending on if I'll be home from school or not.

Nov 10th. I've got plans 12:00-1:00 for the day but hope to be able to make it for opening, but need to leave by 10:30.
https://www.facebook.com/events/1126343787542661/

[rjd_F30]

Originally Posted by Noelified

Nov 10th. I've got plans 12:00-1:00 for the day but hope to be able to make it for opening, but need to leave by 10:30.
https://www.facebook.com/events/1126343787542661/

Ah that won't work for me, was hoping it'd be closer to Thanksgiving when I'll be in around for the holidays, but hopefully you all can get together

[Littlebear]

Originally Posted by rjdnyy224

...In short, CARid is wrong lol. Dinan makes by far and away the quietest aftermarket exhausts for BMW... I don't know about magnaflow, but AWE makes some pretty loud systems. =21[/url]

Thanks rj,
I'm tempted by the Dinan. Most of my driving is on long hiway trips up to the mountains. Five hours with a loud exhaust can be annoying, no matter how good it sounds in the mountains....

If the Magnaflow "Touring" is almost as quiet as the Dinan, that could be cool (love my new Dinan springs)!

Murf