Open baffles & baffle step

[sreten]

Originally posted by Stephen D


Wouldn't that mean that an open baffle has the same initial response roll off as a sealed enclosure? I find that hard to believe as it seems that a sealed merely looses pressure from going from 1/2 space radiation to full space, where as an open baffle has the loss from full out of phase cancellation of the combined front & rear wave to deal with. Also every equivalent comparison I've heard of unequalized open baffle vs. sealed has shown open baffle to be weaker in the bass... open back vs. seal guitar cabs as a simple comparison. What am I missing?

Baffle step causes a 6db step spread over roughly 3 octaves,
thats roughly 2dB per octave centred on the baffle frequency.
Response is flat above and below the step so maximum bass
loss due to the baffle step is 6dB.

Open baffle roll-off is 6dB per octave below the baffle frequency,
the lower you go the more bass you lose very different to BSL.

So you've misinterpreted what I thought I was saying.

And your not missing anything.

sreten.

[sreten]

5thE,

Checkout this bipolar design,

http://www.t-linespeakers.org/projects/tlB/intro.html

it does not need BSC as BS does not occur, though according
to p10 if I'm not misquoting him the designer was unaware of
BSC in normal speakers and that his design didn't have it.

sreten.

[5th element]

Hehe ye i know its not needed thx, I know baffle step and the first octave of dipole 5db drop are not synonomous but they do start at the same frequency, where the soundstarts to diffract. If that brought about any confusion that wasnt the intention.

I am perfectly clear of how it all works must not wonderful at describing it.

[Stephen D]

Originally posted by sreten


Baffle step causes a 6db step spread over roughly 3 octaves,
thats roughly 2dB per octave centred on the baffle frequency.
Response is flat above and below the step so maximum bass
loss due to the baffle step is 6dB.

Open baffle roll-off is 6dB per octave below the baffle frequency,
the lower you go the more bass you lose very different to BSL.

So you've misinterpreted what I thought I was saying.

And your not missing anything.

sreten.

Ahhh... but actually I was kinda missing a full understanding of baffle step... namely the step & the 3 octave spread..!

Thanks.

[aarvin2]

Originally Posted by sreten

Baffle step causes a 6db step spread over roughly 3 octaves,
thats roughly 2dB per octave centred on the baffle frequency.
Response is flat above and below the step so maximum bass
loss due to the baffle step is 6dB.

Open baffle roll-off is 6dB per octave below the baffle frequency,
the lower you go the more bass you lose very different to BSL.

So you've misinterpreted what I thought I was saying.

And your not missing anything.

sreten.

Hi mate, what did you actually mean by BAFFLE FREQUENCY ?

[sreten]

Originally Posted by aarvin2

Hi mate, what did you actually mean by BAFFLE FREQUENCY ?

Hi,

The frequency of baffle effects is directly related to the smallest
dimension of the baffle. for boxes nearly always the width :

f3 = 115 / WB (where WB is the baffle width in meters)
f3 = 380 / WB (where WB is the baffle width in feet)

Here is a sim for a typically medium sized (15"x9") 6.5"/1" 2way :



The 2dB bump at the top is often not correctly accounted for.

rgds, sreten.

[aarvin2]

Originally Posted by sreten

Hi,

The frequency of baffle effects is directly related to the smallest
dimension of the baffle. for boxes nearly always the width :

f3 = 115 / WB (where WB is the baffle width in meters)
f3 = 380 / WB (where WB is the baffle width in feet)

Here is a sim for a typically medium sized (15"x9") 6.5"/1" 2way :



The 2dB bump at the top is often not correctly accounted for.

rgds, sreten.

Thanks for your answer Sir So it means that if I just let a 3 inch speaker play without any enclosure or baffle ... if the width of the speaker is roughly 7cm=0.07m , the 6dB roll off will start at 115/0.07= 1.64 kHz ??

There is something curious though , when the people do measurements for speakers, they measure it alone right ? without any enclosure, and 1m directly in front of the speaker right ?. So it means that if I just create a little frame to mount the speaker, it should reproduce the frequencies just like the speaker graph states, without any problem right ?

Thanks in advance for your help

[atarashi]

Hi,

no, a speaker is normally measured either on an infinite baffle or on a iec baffle, so with a small frame you're going to get the full baflle step! mount it flush into a wall and you're getting close to the "pretty" graph you see from the manufacturer...

Michael

[aarvin2]

Originally Posted by atarashi

Hi,

no, a speaker is normally measured either on an infinite baffle or on a iec baffle, so with a small frame you're going to get the full baflle step! mount it flush into a wall and you're getting close to the "pretty" graph you see from the manufacturer...

Michael

Thanks a lot for your answer Michael!! Damn this sucks though lol ,,, and those guys cheat and play with people's feelings

[aarvin2]

Originally Posted by atarashi

Hi,

no, a speaker is normally measured either on an infinite baffle or on a iec baffle, so with a small frame you're going to get the full baflle step! mount it flush into a wall and you're getting close to the "pretty" graph you see from the manufacturer...

Michael

And it also means that a speaker playing on its own, without being mounted anywhere , has baffle step ... right ?