Hey peeps, Just did some FR measurments using speakerworkshop on my little bookshelves/satillites..
which consist of: peerless 830881 4" nomex phase plug driver mated with a Vifa d26nc-55-06 in a 3.2L vented enclosure, tuned for about 78hz. the tweeter is offset.
the front baffle is 130mm wide by 260 high
Xover is at 3500Hz 12db/oct linkz , I have a 6db amp side series attentuation on the tweeter.
Ive used the method as per claudio negro's guide , with the exeption of induvidual driver measurements.. i.e I did a Gated, on axis with accoustic center. Considering the drivers are so close I figured it will surfice for the moment..
I had some problems with the nearfield measurement due to the phase plug, it prevented me from getting close enough to the driver, so i compensated by moving away from the port aswell.. I think this has had an effect on low freq cutoff as it is around 80hz using a sweep..
anyway I was wondering if anyone has any ideas on the big dipper at 1 and 8k.. it appears on both my far field (non gated) and gate measurments. I tried some slightly different room positions and re marking my points for gating. but it only lessend it slightly.
I also did a simple sine sweep measuremnt with audiotester and had a big dip at 9k again.. noticable around the very bumpy non gated graph.. the 1k dip was impossible to tell as a result.
so does anyone have any ideas, or hints on where I should concentrate on? , could tweeter placement have such a huge impact?
the tweeter certainly would have nothing to do with the 1k dip anyway so Im a bit lost. im quite happy with the rest of the results myself, it looks like I may need a db or so extra attenuation on the tweeter but from a FR pt of view i think the xover points looking ok
any comments, good or bad appreciated!
which consist of: peerless 830881 4" nomex phase plug driver mated with a Vifa d26nc-55-06 in a 3.2L vented enclosure, tuned for about 78hz. the tweeter is offset.
the front baffle is 130mm wide by 260 high
Xover is at 3500Hz 12db/oct linkz , I have a 6db amp side series attentuation on the tweeter.
Ive used the method as per claudio negro's guide , with the exeption of induvidual driver measurements.. i.e I did a Gated, on axis with accoustic center. Considering the drivers are so close I figured it will surfice for the moment..
I had some problems with the nearfield measurement due to the phase plug, it prevented me from getting close enough to the driver, so i compensated by moving away from the port aswell.. I think this has had an effect on low freq cutoff as it is around 80hz using a sweep..
anyway I was wondering if anyone has any ideas on the big dipper at 1 and 8k.. it appears on both my far field (non gated) and gate measurments. I tried some slightly different room positions and re marking my points for gating. but it only lessend it slightly.
I also did a simple sine sweep measuremnt with audiotester and had a big dip at 9k again.. noticable around the very bumpy non gated graph.. the 1k dip was impossible to tell as a result.
so does anyone have any ideas, or hints on where I should concentrate on? , could tweeter placement have such a huge impact?
the tweeter certainly would have nothing to do with the 1k dip anyway so Im a bit lost. im quite happy with the rest of the results myself, it looks like I may need a db or so extra attenuation on the tweeter but from a FR pt of view i think the xover points looking ok
any comments, good or bad appreciated!
sorry ppl ,
no they are not flush mounted at this time, they will be when im decided on a baffle.
do you think that would make such a difference?
here is a pic of my dodgy test box tog ive an idea of positioning of things.
one thing that has concerned me was my need to do a 90deg port bend, something I did not want to do , but really had no choice to keep it a reasonable distance from the reard.. despite making the cabinet very deep
http://www.users.on.net/~majord/peerlessmini.JPG
no they are not flush mounted at this time, they will be when im decided on a baffle.
do you think that would make such a difference?
here is a pic of my dodgy test box tog ive an idea of positioning of things.
one thing that has concerned me was my need to do a 90deg port bend, something I did not want to do , but really had no choice to keep it a reasonable distance from the reard.. despite making the cabinet very deep
http://www.users.on.net/~majord/peerlessmini.JPG
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