single 8" vs. dual 6.5"

[yepimonfire]

thanks for the useful information, i know that the enclosure has alot to do with the low frequencies, and i knew that ported cabinets greatly increase bass. what i was referring to was a book on electronics i was reading, the guy said that bass drivers are larger then mid and high drivers because they have to displace alot more air to reproduce low frequencies. i know that it all has to do with the amount of displacment of air which is why 5mm drivers can produce 15hz extensions when use in the ear because there is way less air to move, i also know that i have tons more bass in small rooms with my bookshelfs but if i place them in the living room, they dont do so well. its not about room acoustics in this case because this effect happens to me no matter what room i am in or what house i am in ( i have moved several times) smaller rooms always have more bass with bookshelfs for me. now as far as i know, the reason a port increases the extension is because it allows the LFs to fully extend within the cabinet beyond the length of the cabinet.

if im wrong on any of this i would rather be corrected then misguided. thanks again for the above post.

secondly can you further explain what you mean by this

In fact at box tuning the speaker cone virtually stops still, and then decouples below that and stops being an effective radiator.

 

[JerryLove]

You seem to have no concept of how a speaker actually works. Speaker size per se does not enter into low frequency extension.

Not to pick on your post specifically, but it is endemec.

No one asked which would go lower.

The question was "which do you think would sound better bass wise?"

Now we were given no information at all about the speakers other than size. We were also give no information about what "better" meant.

Since, *all else being equal*, a larger surface area will move more air (higher SPL), I answered the question asked while pointing out that there is *far* more involved.

Many people with a great amount of knowledge, including yourself, have given a great deal of correct information... but little of it seemed to be answering the question that was asked.

So unless there is a 1" driver out there that will do 110db @ 20Hz @1m, size is a factor in combines SPL-FR output. And while it's entirely possible for a good 8" to go lower and louder than a bad 15", that wasn't what appears to have been asked.

So to reanswer the question asked: It's impossible to tell from the little information given which will actually sound better.

Simple: All else being equal, the dual 6.5 would have a higher SPL

Correct: The dual 6.5 has more surface area, and therefore moves more air at a given excursion. This begins to tell us about the ability to generate SPL at low frequencies: though there are many other factors which will come into play in both driver design and cabinet design.

...and while we are being anal about why we can't answer: the speaker you place in the corner will likely sounds "bassier" than the one you put in the middle of the room.

 

[JerryLove]

the guy said that bass drivers are larger then mid and high drivers because they have to displace alot more air to reproduce low frequencies.

Close enough.

i know that it all has to do with the amount of displacment of air which is why 5mm drivers can produce 15hz extensions when use in the ear because there is way less air to move,

Not because there is less air: because you are closer. Also because of baffle (see below)

i also know that i have tons more bass in small rooms with my bookshelfs but if i place them in the living room, they dont do so well. its not about room acoustics in this case because this effect happens to me no matter what room i am in or what house i am in

Of course it's room acoustics.

Imagine that sound is smoke. Sound volume is about the density of smoke against your ears. Release a given amount of smoke in a little room and it might be pretty thick. Release the same amount in a big room and it's much less thick (more quiet).

Without spending too much time explaining why (because I'm sure many will point out that I'm simplifying), under normal "in room" conditions: LF is non-directional and HF is directional... so bass volume is more dependant on room size.

now as far as i know, the reason a port increases the extension is because it allows the LFs to fully extend within the cabinet beyond the length of the cabinet.

a port uses the sound coming out of the back of the driver (the pressure) to make sound. See a few posts up for a better explanation from someone more knowledgeable than I.

 

[bandphan]

moving hot air should have been the question

 

[yepimonfire]

what i meant was SPL of course larger drivers can generate more SPL, when used in a system containing a crossover which has a low pass of around 200hz a larger driver can generate more bass because it is able to generate more SPL from 200hz on down.

 

[JerryLove]

Assuming the same excursion. Another way to move air, besides the size of the cone is the distance the cone moves... and all that assumes similar cabinets.

 

[yepimonfire]

true...........

 

[bandphan]

Start here, then move up in knowledge database

 

[ski2xblack]

secondly can you further explain what you mean by this..."In fact at box tuning the speaker cone virtually stops still, and then decouples below that and stops being an effective radiator. "

http://www.hometheaterhifi.com/technical-articles/170-a-big-dig-into-bass-reflex.html

Scroll down to the animations demonstrating the speaker/port behavior above, at, and below resonance for an excellent visual explanation to your question.

 

[Seth=L]

I agree and disagee. The Behringer 2030Pis a great speaker , much much better than the two Sony speakers you are looking at.

However, I humbly dispute the statement "You won't do better for the money, anywhere". I will put Cambridge Audio S-30s up against the 2030Ps anyday.

The Cambridge Audio S-30 is about the same as the Behringer 2030P but comes in a little neater, cleaner, more asthetic package. You can get them in black or a natural wood finish.

The are around $199 -$219 a pair .http://www.audioadvisor.com/prodinfo.asp?number=CAS30 BLK

A review: http://www.testfreaks.com/hifi-speakers/cambridge-audio-s30/


I also have them installed as the primary speakers in my National Woods Cabin

However, restating, I agree with WmAx (Chris) the Behringher 2030Ps are aslo excellent speakers.


Peace and Good Sound,

Forest Man


P.S.- An inexpensive but great sounding subwoofer is the Dayton SUB-120 HT for as little as $120 from Parts Express http://www.parts-express.com/pe/showdetl.cfm?partnumber=300-635&source=googleps

Although those a nice little speaker, I doubt they compare sonically to the 2030p.