tapped horns - a different perspective & an alternative

[GM]

I would say, the engeneering of speakers is definitely technical and nothing more.

I agree, design according to physics like the pioneers of audio did, then let the individual 'voice' it to personal preference since we all perceive the subtleties of sound differently.

GM

 

[Scottmoose]

Amen.

 

[Scottmoose]

???????????

I confess I was thinking Karlson myself when I first read this thread. Glad it's not just me.

 

[ShinOBIWAN]

I think I would have to totally disagree with that. I tend to think that you cannot separate one from the other.
The design of speakers is all about the perception of music. !!!!

I'd have to agree Andy.

From the initial idea and the design blueprint through to the realisation its almost all purely technical work. Sure the implementation specifics will likely be guided by personal preferences but how those choices are progressed through to something workable should always be done from a technical foundation. However as soon as it plays for the first time, no matter how much technical prowess you have, you always go back and work the details to get that most subjectively rewarding sound.

A good loudspeaker comes from a dollop of both and one without the other is likely to turn out to be the poor relation.

 

[sreten]

Re: Re: Re: tapped horns - a different perspective & an alternative

ok lets keep tapped horns out of this until we're done with my horn.

if they're so smart they can figure out what i'm telling them without any sims.

if not, then they aren't worthy of my ideas

Hmmm......

Lets take your horn. It simply does not work as described.
Consequently its not a good idea / does not do anything useful.

If you think half baked ideas based on misinderstanding of theory
represents "original ideas" worthy of attention you are mistaken.

FWIW at low frequencies output of vent is 180 degrees out of phase
with the frontal driver output and in phase with the rear radation.
At the vent frequency it is in phase with frontal output and out of
phase with the rear radiation.
Above port frequency it tends towards 90 degrees but output is
rapidly falling and will contribute liitle to the total output of the
front horn loaded driver.

Below vent frequency it is effectively the same as the box and
port not being there, i.e. free air loading, and given the suggested
port frequency in its range of operation its contribution to the
total output would be minimal.

Is it a bad idea ?
Is free air rear loading a bad idea is the question .........

/sreten.

 

[phase_accurate]

Furhtermore ideas like this are not even new at all ! There are heaps of horn - bandpass/resonator combinations out there.

And I guess that group-delay of such thingies is even higher than the tapped horn's.

Regards

Charles

 

[vasyachkin]

"I should not even stress more that I do not like people at DIYAudio.com. The domination majority of them incredible idiots and the brightest among them… do not really have any perspective what audio is all about."

i kinda take it for granted that people are idiots and have no clue about anything.

thats not a reason to dislike people though. i like people around here, i really do.

what i don't like is being banned (even temporarily) when im trying to have a serious discussion.

it seems the only real difference between me and Romy is my English is better lol ... but anyway i had to do the same thing that he did - upon being banned from here i started my own forum.

you can participate in testing the forum here

"Advertising deleted by Moderators"

let me stress it again - i never had problem with people here. only with the moderation.

come and say helo ...

 

[vasyachkin]

Re: Re: Re: Re: tapped horns - a different perspective & an alternative

FWIW at low frequencies output of vent is 180 degrees out of phase
with the frontal driver output and in phase with the rear radation.
At the vent frequency it is in phase with frontal output and out of
phase with the rear radiation.
Above port frequency it tends towards 90 degrees but output is
rapidly falling and will contribute liitle to the total output of the
front horn loaded driver.

Below vent frequency it is effectively the same as the box and
port not being there, i.e. free air loading, and given the suggested
port frequency in its range of operation its contribution to the
total output would be minimal.

 

[vasyachkin]

we need to straighten this phase issue out as its fundamental to understanding this ... now i think actually everybody was wrong on it including myself.

i thought about it some more and here is my new and revised understanding of port phase behavior

i will express the port phase with respect to the REAR wave from the driver so you can add your own 180 degree shift

way below tuning - port delayed 0 degrees

at tuning - port delayed *almost* 180 degrees

above tuning - port delayed 180 degrees

do you agree ? do you want to hear my argument for why this is so ?

i think this time i finally got it right because this actually explains the behavior of vented boxes completely while my previous understanding (90 degree delay) only explained it partially and not very well at that.

my mistake was to think that since vent is like an inductor then it must introduce 90 degree delay ... but i forgot that there is another 90 degree delay between speaker velocity and air pressure so the total delay is 180 degrees ...

 

[vasyachkin]

I understand, but the vent rotates phase 180 degrees near resonance and goes back to 0 degrees below resonance. You would need a horn producing full 360 degrees of phase shift at the frequency where the vent resonates. and still 180 degrees below resonance to get some summing. This calls for a very long expansion (one wavelenght of tnuning freq).

It shouldn't be hard to simulate with hornresp, the pity is that it doesn't allow you to set vented chamber Q and it assumes a too high value.

ok you were right. what this means in practical terms is that my design will work even better than i originally planned because the port produces twice as much phase shift as i thought it does.

in a revised design lets tune the port to 3/4 wave frequency.

then at 1/4 wave frequency the front is delayed 1/4 and the rear 2/4 and the difference between front and rear is 90 deg

at 2/4 wave the front is delayed 2/4 and the rear 2/4 the difference is 0 degrees

at 3/4 wave the front is delayed 3/4 and the rear 4/4 the difference is 90 degree (with optimum port damping i think the rear wave should be delayed 3/4 octave and summation should be perfect 0 degree)

and 4/4 wave the front is delayed 4/4 and the rear 4/4 the difference is 0 degree

in other words the phase shift between front and rear never exceeds 90 degrees which is non-destructive and it hits a perfect 0 degrees summation at two points a full octave apart with no cancellation between these two frequencies (and possibly even perfect tracking throughout the entire octave).

the reason all this works is that the mass of the port delays the rear wave proportionally (more at high frequencies and less and low frequencies) to the way the length of the horn delays the front wave (also more at high frequencies and less at low frequencies) and the result that front and rear waves track each others phase for an entire octave instead of summing perfectly at only a single frequency as in a normal horn.

the horn then realizes more than 2 octaves of bandwidth ( from 1/4 wave frequency to 5/4 ) totally free of any cancellation between the front and rear wave and the first "null" will appear at 6/4 wave but this will be at twice the port tuning frequency at which the port output will be minimal.

these 2 octaves of bandwidth perfectly cover the subwoofer range of 20hz to 80hz so this makes for a perfect horn subwoofer ...

 

[vasyachkin]

to construct the speaker in practice (given that it cannot really be modeled) i would simply use a rear volume of about half the size that would be used for a sealed box and then tune it using trial and error by cutting different length ports but starting with 3/4 wave frequency and varying both the port length and amount of damping.

 

[Scottmoose]

i kinda take it for granted that people are idiots and have no clue about anything.

And that patronising attitude, if you'll forgive me, pretty much sums up why you get a large number of people's backs up. Many of whom are rather good at speaker design.

Oh, sorry, I forgot: we're 'not worthy' (your words) of your exalted self.

 

[vasyachkin]

you're taking me out of context.

i was asking people for opinions on a design. certainly if a person does not understand the design than his opinion of that particular design is not very important.

my point was that if you do not understand something you have no right to judge it.

 

[454Casull]

you're taking me out of context.

i was asking people for opinions on a design. certainly if a person does not understand the design than his opinion of that particular design is not very important.

my point was that if you do not understand something you have no right to judge it.

That is completely different from what you said before.

 

[vasyachkin]

LOL

but i probably meant something along those lines.

 

[eeraudio]

hello to all im new in the line, but i love music, can anyone point me to right direction?

 

[weltersys]

hello to all im new in the line, but i love music, can anyone point me to right direction?

For someone to "point you to right direction", you need to say where you want to go, but this zombie thread ain't going nowhere.

 

[sreten]

hello to all im new in the line, but i love music, can anyone point me to right direction?

Hi,

Why on earth have you posted in this thread ?
A load of nonsense posted by a clueless bigot.

rgds, sreten.

 

[JLH]

Sy, it might be time to go ahead and lock this thread and throw it away.