Why do earbuds have better bass response than 4-in speakers? Explain to my wife.

So my wife and I are getting a teardrop trailer and I'm buying some 4-inch coax speakers. This is the max size that will fit where there need to go.

I'm ready to pull the trigger on these:
http://www.crutchfield.com/S-mXeq5j9yFoS/p_107DXI400/Polk-Audio-DXi400.html?tp=102#details-tab



Then my wife says "the low-end frequency range isn't very low (85 Hz)"

I say, that's the way it is with small speakers. They just don't have a big enough woofer to produce lower frequencies.

She says, then why do my earbuds and other headphones have good bass?

That's a damn good question.

And I'm like, uh, it is because they are so close to your eardrum and in an small enclosed space...I don't f'ing know!

She was not convinced. And I don't know if I am right. It is a guess based on obvious physical differences, but I can't back it up with data or definitive. Can you?

I just looked up very high-end 4-inch Focal separates with crossovers, figuring that is someone could milk low end out of little speakers, it would be focal, but they had even less low end at 91 Hz. go figure. Granted, they assume you'll have a sub somewhere else doing this job.

http://www.crutchfield.com/p_091I100VRS/Focal-Integration-100-VRS.html?tp=102#details-tab

I just looked up earbud base and CNET is showing them with 20 Hz low end!
http://reviews.cnet.com/earbuds-with-the-boomiest-bass/

So, audio geeks, who can explain why tiny earbud or headphone speakers can produce lower-end freqs than 4-inch car speakers?

 

I'm not qualified to answer why the bass is heavier in ear bud's but I do know that if you amp your speakers with a 50x2 amp it'll help bring the bass out in the speakers.

 

Yeah, there won't be subs. This is a very compact space, and we don't want to draw down the trailer's battery with an amp, especially if we end up getting an Engle fridge later...

but even with an amp, which I know would get more out of the speakers, especailly at lower volumes, I woldnt' expects a profound inprovement in low end from a 4-inch speaker. Would you? Have you?

I'm looking at a Kenwood HU with a higher than average RMS and also some equalization settings that allow you to pick speaker size, which sounds pretty promising for a tweak. Problem is, you can never find everything you want to actually listen to the system in a single store.

 

Yeah, so frequncy ratings can be melarky or misleading, but I don't see an explanation of the physical difference I am talking about (unless I missed it?). Regardless of spec, you can simply hear the difference beween the low end on decent headphones and small car speakers.

BTW, my wife is an engineer, so I can't just throw data at her and expect her to be baffled. She will analyze it.

 

Depends on the RMS of your deck..you may see little if any gain over that using a 50x2 amp. Some head units already offer 40/45/50 RMS. What's the model# you're eyeballing?

I would (educated guess) say your bass response is due to the enclosed space between the earphone and ear, versus the space you're filling in a truck. I have a set of headphones at work that cover the entire ear (old DJ style) and the bass on those is great even though they are a no-name brand.

 

That was my "educated guess" too. Just trying to look for something to substantiate it more scientifically.

This is the HU:
http://www.crutchfield.com/p_113KDCX796/Kenwood-Excelon-KDC-X796.html?tp=5684#details-tab

RMS is 22w, max 50w.

This is for a camping trailer, not the truck. I am trying not to break the bank on equipment here.

I have other plans for the truck

 

Care to paste a quote in here?

I'll read a little more closely tonight. I am burning a vaction day to repair the front door to the house...pain in the ass fixing other people's shoddy work, but I have to have it buttoned up ASAP.

And I know you have a thing for librarians.

 

I'd say with that radio, you'd be just fine versus spending for an amp..the little gain you "might" see I don't think is worth the extra cost. Now if you were looking to get more towards 100x2 I would say pull the trigger, but that would be different plus like you said this isn't a daily driver.

 

I'll try to locate something better for the original question, but I would also demonstrate by using a pair of earbuds on your MP3/CD player. Put them in the ear first. Now take them out and hold them 6 inches away. That's a good way to demonstrate what I said before in the meantime..

 

Yeah, that was basically my intuitive reasoning. Stock iPod earbuds sound (and feel) awful, but I found some molded covers that channel the sound into your ear canal, and it's like listening through my full-size Sony MDR monitor headpones. Enclosed space is a world of difference.

 

In order to hear bass there needs to be a certain amount of air movement and pressurization. With earbuds you are pressurizing about about 0.5 cubic inch of airspace in your ear canal. You are doing this with about a 10mm or almost 0.5 in speaker. So the speaker is very big compared to the air volume that it is pressurizing. Headphones that sit on your head pressurize a larger volume that includes your ear canal and outer ear so they use almost 2 inch speakers.
Now think of the airspace of your truck, it's WAY bigger, so you need WAY more power and much larger speakers to move enough air to pressurize it enough to hear and feel bass.

Hope this helped.

 

basically, what El Taco said. If you take that 4" speaker and cup it to your ear, you can get some surprising bass out of it. The diameter of the speaker coupled with the travel of the speaker cone tells you how much air you can displace. For earbuds, they only have to displace a fraction of the ear canal volume. For the inside of a truck, they have to displace the same fraction but of the volume of the cab.

There is some other things at work such as the resonance of the speaker due to mass and stiffness but the big part is simply being able to move the appropriate amount of air.

As an engineer, she should be able to go back to her undergrad physics and work out an understanding of the phenomenon.

 

Yeah, if she's so smart, make her explain it to you. In my experience, SOME engineers are the dumbest smart people out there, common sense wise.

 

You pretty much nailed it.

With earbuds, there is very little loss between the speaker and your eardrum.

Remember... your eardrum is about the same size as the speaker in the earbuds and it has no problem reproducing sounds that are outside of our ability to hear.

With a speaker, it has to move hundreds of cubic feet of air before the pressure wave gets to the eardrum. There are a ton of things in that airspace that attenuate (and resonate) various frequencies.

30+ years ago, if a speaker didn't have a high frequency horn, 3" tweeter, 8" midrange, and 12" woofer, it wasn't given a 2nd look.

Technology improved, and "bookshelf" speakers moved in, and some even had decent bass response, but you still needed (and still need) a sub for room-filling, full spectrum sound.

But even a 4" woofer can produce some awesome sound, provided the cone has enough excursion and it is in a properly designed enclosure.



There's a lot of science, and more than a little voodoo involved with acoustic design.