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Hornresp Diaphragm Displacement

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SouthwestCNC View Drop Down
Young Croc
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SouthwestCNC Quote  Post ReplyReply Direct Link To This Post Posted: 23 January 2018 at 1:59pm
Originally posted by DMorison DMorison wrote:

Originally posted by SouthwestCNC SouthwestCNC wrote:

Originally posted by snowflake snowflake wrote:

post your input screens and will have a play...


Feel free to



Don't think it'll have a major effect, but your inputs aren't quite right for using the OD layout option.
Remember the length at S2 needs to line up with the centre of the cones (i.e. 28.2cm), you'd then need S2-S3 to add up to the rest of the length of the straight section (i.e. 28.75cm) before the slight flare and use S3-S4 for that last part.

HTH,
David.


OFC.. Thanks david. Response wise sligly closer to measurments, Impedance further from measured. displacement reduced by couple of mm per hz.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 23 January 2018 at 2:17pm
if the drivers are facing each other you need several litres of front chamber volume to represent the air inside the speaker cones. has a small effect on response.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 23 January 2018 at 2:27pm
also, the length of the rear chamber is not 86cm. if you want to model resonances in the rear chamber it should be the average distance from the back of the cone to the wall behind it (in this case the side of the speaker). to model the interaction of the front and rear output I thought you would want the chamber length to be the average distance from the rear of the cone to the centre of the rear vent. this would enable modelling of phase differnces and interference between the horn and vent outputs. However, trying it now, with the 'masked' option selected, the depth of the rear chamber does not seem to have any effect on the combined output implying that the rear path length is not being used to model the combined output.

Perhaps David can clarify how this works?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mobiele eenheid Quote  Post ReplyReply Direct Link To This Post Posted: 23 January 2018 at 2:41pm
Quote However, trying it now, with the 'masked' option selected, the depth of the rear chamber does not seem to have any effect on the combined output implying that the rear path length is not being used to model the combined output
That is what the mask resonances option is for. Do not mask resonances for the influence on the frequency response (which is usually out of the pass band of a sub woofer).


Edited by mobiele eenheid - 23 January 2018 at 2:42pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 23 January 2018 at 2:54pm
Originally posted by mobiele eenheid mobiele eenheid wrote:

Quote However, trying it now, with the 'masked' option selected, the depth of the rear chamber does not seem to have any effect on the combined output implying that the rear path length is not being used to model the combined output
That is what the mask resonances option is for. Do not mask resonances for the influence on the frequency response (which is usually out of the pass band of a sub woofer).


yes, but there are two effects. one is the resonances which occur in all speakers with a rear chamber - sealed, FLH etc. the other is the interaction between the front and rear outputs. I thought that the masked option only disabled the first one.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SouthwestCNC Quote  Post ReplyReply Direct Link To This Post Posted: 23 January 2018 at 2:58pm
Originally posted by snowflake snowflake wrote:

also, the length of the rear chamber is not 86cm. if you want to model resonances in the rear chamber it should be the average distance from the back of the cone to the wall behind it (in this case the side of the speaker). to model the interaction of the front and rear output I thought you would want the chamber length to be the average distance from the rear of the cone to the centre of the rear vent. this would enable modelling of phase differnces and interference between the horn and vent outputs. However, trying it now, with the 'masked' option selected, the depth of the rear chamber does not seem to have any effect on the combined output implying that the rear path length is not being used to model the combined output.

Perhaps David can clarify how this works?


Just tried this and found electrical impedance to have increased considerably from 18 sound plot. was infact very similar before at 86. But good to know how it should have been done.


Not that I understand why the result is further from real world tho.



Edited by SouthwestCNC - 23 January 2018 at 3:00pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SouthwestCNC Quote  Post ReplyReply Direct Link To This Post Posted: 23 January 2018 at 3:13pm
revised



-15ltr from VRC for volume taken up by driver.

Ignore my last comment regarding impedance, I was looking at this cab simmed as a single in 1. pi, half figures. In this sim the impedance was higher. this down to the half horn do you think?



Edited by SouthwestCNC - 23 January 2018 at 3:22pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gen0me Quote  Post ReplyReply Direct Link To This Post Posted: 23 January 2018 at 4:33pm
Originally posted by snowflake snowflake wrote:


yes, but there are two effects. one is the resonances which occur in all speakers with a rear chamber - sealed, FLH etc. the other is the interaction between the front and rear outputs. I thought that the masked option only disabled the first one.

Second one is "combined output" distance in acoustical power options or patch length in wizard in chamber options.
First one is not important in bandpass can show up in bass reflexes as they play higher.

Btw do you calculate mmd or put it as mms?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SouthwestCNC Quote  Post ReplyReply Direct Link To This Post Posted: 23 January 2018 at 4:36pm
Originally posted by gen0me gen0me wrote:

Originally posted by snowflake snowflake wrote:


yes, but there are two effects. one is the resonances which occur in all speakers with a rear chamber - sealed, FLH etc. the other is the interaction between the front and rear outputs. I thought that the masked option only disabled the first one.

Second one is "combined output" distance in acoustical power options or patch length in wizard in chamber options.
First one is not important in bandpass can show up in bass reflexes as they play higher.

Btw do you calculate mmd or put it as mms?

I calculated.. should i have used mms?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote mobiele eenheid Quote  Post ReplyReply Direct Link To This Post Posted: 23 January 2018 at 6:42pm
No, Mms is higher as Mmd, so calculating is the way to go.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 24 January 2018 at 11:58am
Originally posted by gen0me gen0me wrote:

Originally posted by snowflake snowflake wrote:


yes, but there are two effects. one is the resonances which occur in all speakers with a rear chamber - sealed, FLH etc. the other is the interaction between the front and rear outputs. I thought that the masked option only disabled the first one.

Second one is "combined output" distance in acoustical power options or patch length in wizard in chamber options.


from the hornresp help file:
" The path length from the rear side of the driver diaphragm to the port
 outlet is assumed to be equal to Lrc plus Lpt, as shown in the schematic
 diagram.
 
 The distance from the port outlet to the listener can be adjusted if
 necessary using the path length difference parameter.  A positive value for
 path length difference increases the listener distance.
 
 The path length difference is the distance from the port outlet to the
 listener minus the distance from the direct radiator diaphragm to the
 listener.  The difference is positive when the distance from the port
 outlet to the listener is greater than the distance from the direct
 radiator diaphragm to the listener."
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 24 January 2018 at 12:13pm
so rear chamber length should be the average distance from the cone to the start of the vent. if there is no vent make the rear chamber length the distance from the cone to the rear wall parallel to the driver. Is that the right way to use Hornresp?


Edited by snowflake - 24 January 2018 at 12:15pm
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