Is15 inch overkill for music?????experts

[till]

Cal,

The drivers are TAD, see here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=7032&highlight=

The horn is diy, descripion also in th thread.

History for choosing this project:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=6164&highlight=
http://www.diyaudio.com/forums/showthread.php?s=&threadid=6083&perpage=15&pagenumber=1

behind the port you can see the piece of wood that is used to make the corner of panels of plywood.

The ports tuning is not ready yet, Kent at passlabs wants to make some measurements at his enclosures, and i´m notz sure how to tune at the moment. I made this:
http://home.tu-clausthal.de/~tpa/port/index.html

But conditions for measuremnt are very bad in the room i use at the moment. So the measuremnt doesn´t tell too much.

 

[bremen nacht]

>As for namecalling, I was not going on about anyone personally, I referred in robust anglosaxon to a commonly repeated chestnut of a pseudo theory on >acoustics.

As your post was deleted, we don't know which chestnut you refer to - can I guess that it was the one abou how you can't hear 20Hz unless your room is 500m long?

 

[cocolino]

originally posted by Kuei Yang Wang
And this theory remains exactly what I analysed it as (in the strict chemical sense I may add) no matter how often repeated by those who prefer to parrot others poorely researched and argued theories as fact because they seem to fit with personal prejudices, instead of informing themselves about the facts.

I don`t want to begin an off topic discussion about semantics and what is rather rude manner of expression or what isn`t .

The above is all true - but still though - there are other and IMO better ways (more polite or respectful if You will) to proof others being wrong (and apparently I`m not the only one feeling this way).

I understand that everybody can just have had a bad day... so case closed what concerns me

 

[ThorstenL]

Konnichiwa,

>As for namecalling, I was not going on about anyone personally, I referred in robust anglosaxon to a commonly repeated chestnut of a pseudo theory on >acoustics.

As your post was deleted, we don't know which chestnut you refer to - can I guess that it was the one abou how you can't hear 20Hz unless your room is 500m long?

Yes, the sameself one. BTW, it would also mean you cannot hear 20Hz unless your ear channels are 17.25m (the wavelength of 20Hz) long.... In fact, if that theory held the least bit of water you hear nothing below something closer 2KHz, which most people actually. Though for those who don't it may explain the view that "small speakers are just fine".... ;-)

Sayonara

 

[5th element]

KYW - I agree with all of what you have said about drivers appart from one thing. And unfortunately for me as im sure im gonna get an ear bashing for it, as you anglo saxonismed it before LOL, is the 20hz in the ear canal.

I do understand that obviously we can hear down to 20hz with headphones. But I have heard time and time again, that with a smaller room it is harder to get a flat response down to a given frequency. Not that you cant hear or produce a low freuquency in the small room, but more you have got to move more air in the smaller room then a larger room for the same SPL at low Hz.

If this is not really the case, then it must have been simply room interaction other then the above, that contributed to the improved low extension when I moved my speakers into a larger room.

Cheers Matt

 

[jewilson]

Matt

Your are correct, you cannot here low frequencies in your ear. You are feeling sound pressure of the pulse.

If fmin = V / (2*L) = 172/ L is used in determining the room modes or resonaces. And this is obvious since, the bigger the room it is, the lower the modes and less troubling.
What I am saying is. A certain frequency can be produced properly only if the associated wavelength "fits" in a room's dimension. If L = V / f, so you need a minimum length of 17.2m. for a 20hz frequency to be produced properly. Other wirse are your lessening to standing wave and room modes.

http://www.mcsquared.com/metricmodes.htm

http://www.linkwitzlab.com/rooms.htm

 

[thylantyr]

I guess the key word in the first post is 'overkill'. The definition
of overkill is variable depending on who you talk to. Since
everyone has different needs, the answers given never agree.

I'm going to use six 15" in my home stereo project because
I like it.

 

[Bill Fitzpatrick]

I'm going to use six 15" in my home stereo project because
I like it.

Good for you. I use 8 12" myself.

 

[cocolino]

Originally posted by Bill Fitzpatrick
Good for you. I use 8 12" myself.

.....and my plan is to use 8 (4 per channel) 10" long-throw Scan-Speak`s.
That`s an equivalent total diaphragm area of approximately 4 times a 15" driver - but with much higher linear X-max. than 15"ers usually can do

 

[ThorstenL]

Konnichiwa,

I do understand that obviously we can hear down to 20hz with headphones. But I have heard time and time again, that with a smaller room it is harder to get a flat response down to a given frequency.

Actually, VERY LOW frequencies (these below the lowest room mode) are easy peasy. It is more interesting in the range where the room is modal (I would link here my little treatsie on using the Behringer EQ in if Yahoo would not prevent me from sharing it - the salient points are reposted below), meaning subject to many pertubations due to the room modes.

Actually, two easy soluitions exist for room modes:

1) Parametric EQ's (digital or other).
2) Use of Dipole (figure 8) or Unipole (Cardiod) woofers.

Sayonara

Behringer and room acoustics treatsie:

http://groups.yahoo.com/group/Thunderstone_technical/files/TL Circuits/Ultracurve/Behringer target curves.html

 

[Variac]

I keep hearing about wavelaunch. Anyone wish to enlighten me?

 

[bbaker6212]

dipole subs

So KYW, it seems you are saying that dipoles are a good way to go for subs. What do you think about the W and H shaped open baffle dipole subs like these? They seem like a good way to make the cabinets smaller (ie, turning the 15-20" drivers sideways).

 

[jewilson]

Variac,

Wavelaunch; isn't that when high tide goes out

I really have no idea, but it must be good.

 

[Variac]

Well, it seems to be related to the frequency.
Maybe I'll wander down to the beach to ponder.....thanks for the idea

 

[jewilson]

Bill Fitzpatrick,

Let see a picture of these monsters with the 8each 12" drivers.

 

[jewilson]

Now this is my idea of a good, great 15" driver.

 

[thylantyr]

My favorite 15" woofer.

http://www.lambdacoustics.com/drivers/TDdrivers.html

Specifically TD15H Apollo motor. The picture shows the old phase
plug, the newer ones are much longer - a manly woofer - lol

The sonics are superb when listening to it full range.

I should have a total of ten of these soon.

/yummy

I think this is the old protoype chart of the TD15X.
http://www.lambdacoustics.com/funstuff/TD15X.html

The DIY section of his website. This looks fun, unity horn.
http://www.lambdacoustics.com/images/unity/family/pspkr.jpg

http://www.lambdacoustics.com/images/unity/family/majestic ladies.JPG

 

[DrSplodge]

Whats wrong with Adires 15" Tempest?

Isn't that a good candidate 15" also?


Over and out.....javascript:smilie('')

 

[jewilson]

These TD15H Apollo look cool, The only thing I did not care for was the PVA Coated Foam Surround.

I have heard the Focalsand the red magnets look cool. I wood have a had time parting with the cash for a driver that cost so much with out having heard it. So I am out of luck.

http://flexunits.com/iz.asp?id=4|a|119||| these units look nice but big bucks.

 

[slowmotion]

When You replace the word music with the word bass above I fully agree with this.

Actually IMHO all the way into the lower midrange.

At the moment I am using 2 15" woofers per side in open baffles,
from ca 40 to 270Hz , horns cover the rest.

cheers