I have just completed building a two way transmission line using the Vifa P17WJ and D27AG speakers
I used a crossover from the local Vifa distributor at the time I bought the drivers (Attachment #1).
I also found a circuit for just the tweeter from VIFA themselves, which I didn’t used (Attachment #2).
The results of aural tests using audio CD tracks was less than satisfactory as there was a pronounced harshness in the upper register (particularly brass & cymbals) with strong sibilants on some high female voices.
Attachments
#1 Two way Crossover - used
#2 Tweeter crossover - not used
Any possible clues as to the cause of this would be greatly appreciated
I used a crossover from the local Vifa distributor at the time I bought the drivers (Attachment #1).
I also found a circuit for just the tweeter from VIFA themselves, which I didn’t used (Attachment #2).
The results of aural tests using audio CD tracks was less than satisfactory as there was a pronounced harshness in the upper register (particularly brass & cymbals) with strong sibilants on some high female voices.
Attachments
#1 Two way Crossover - used
#2 Tweeter crossover - not used
Any possible clues as to the cause of this would be greatly appreciated
Attachments
Here we go again. Vague pronouncements about a problem and 30 posts to fix "it".
Obviously your bass is too weak. Or room too hard. Or ears unfamiliar. Or it is the polar pattern. Or tweeter distorting. Or pop-music sizzling test records. Or comb filtering*. Or sound is perfect but good treble is new to you.
How about some measurements first instead of wasting everybody's time.
B.
*OK, I don't believe there is such a thing effecting human perception, but thought I'd throw that in anyway
Obviously your bass is too weak. Or room too hard. Or ears unfamiliar. Or it is the polar pattern. Or tweeter distorting. Or pop-music sizzling test records. Or comb filtering*. Or sound is perfect but good treble is new to you.
How about some measurements first instead of wasting everybody's time.
B.
*OK, I don't believe there is such a thing effecting human perception, but thought I'd throw that in anyway
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Hi Ken,
As pointed this is not easy to point without more info. Do you have measuring gear (microphone and soundcard with mic input including phantom power?)?
Could you post some pictures of your build?
Ben, please don't be so harsh sounding to newcomer ( haven't you spoted the join date?) and remember we all started at one time or another.
About comb filtering well if human wasn't sensitive to combfiltering ther would not be a full market of chorus, phaser, flanger or filter effects for musicians to use! Maybe they are all subject to placebo effect but hey, this start to make a looootttt of people fooling themself no? And a lot of tracks use this effects to great results in recent 'pop' history... If you don't hear the flanger on Lenny Kravitz's guitar riff on 'are you gonna go my way' (from 2"11 to 2"25) well... nothing more to say.
I'm would happily treat any file you send me to proove you we (you) are sensible to combfiltering.
As pointed this is not easy to point without more info. Do you have measuring gear (microphone and soundcard with mic input including phantom power?)?
Could you post some pictures of your build?
Ben, please don't be so harsh sounding to newcomer ( haven't you spoted the join date?) and remember we all started at one time or another.
About comb filtering well if human wasn't sensitive to combfiltering ther would not be a full market of chorus, phaser, flanger or filter effects for musicians to use! Maybe they are all subject to placebo effect but hey, this start to make a looootttt of people fooling themself no? And a lot of tracks use this effects to great results in recent 'pop' history... If you don't hear the flanger on Lenny Kravitz's guitar riff on 'are you gonna go my way' (from 2"11 to 2"25) well... nothing more to say.
I'm would happily treat any file you send me to proove you we (you) are sensible to combfiltering.
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Sorry, while I did think of edge diffraction, I thought comb filtering was as silly an idea as I wanted to list, even skeptically.
B.
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I've posted FR plots to show a Mac laptop mic is good enough for such purposes, along with honour-ware REW.
My footnote was intended to mean I am skeptical that comb filtering matters in a room.
B.
While a bit more research is needed, I'm really starting to think that all newcomers ought to be directed to download a bit of cheap FFT ( or RTA ) software for use on their smartphone ( obviously, to be able to provide measurements to share with the "Helpers" ).
Response irregularities ( and crossover issues ) are easy enough to identify at 1/6 octave smoothing and a "readable" 5db ( per line ) vertical scale.
A smart-phones builtin mic isn't the best, but I believe they are adequate for many "Help-Me" threads like this one.
I really think if you are not interested in a project, you should just stay away from it.
Ken Clark, welcome to our little forum. You will discover that some folks here are willing to help, and some folks are just so full of themselves they just want to show off their superior knowledge and belittle others. While being a bit short on detail.
You were a bit vague on the tweeter, and the details matter. But it sounds to me like your worst problem is the tweeter is too loud. Easily fixed.
These seem to be well-behaved drivers that ought to be easy to integrate. So check the tweeter model serial number. The woofer is just plain easy for 2.5kHz crossover.
Ken Clark, welcome to our little forum. You will discover that some folks here are willing to help, and some folks are just so full of themselves they just want to show off their superior knowledge and belittle others. While being a bit short on detail.
You were a bit vague on the tweeter, and the details matter. But it sounds to me like your worst problem is the tweeter is too loud. Easily fixed.
These seem to be well-behaved drivers that ought to be easy to integrate. So check the tweeter model serial number. The woofer is just plain easy for 2.5kHz crossover.
Attachments
I listed seven possible causes for the OP's problem. Didn't notice?
Against rules of the forum and plain courtesies, you repeatedly attack me on the personal level. I wish the moderators would have a few words with you.
B.
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Thanks Steve,
Full details of the tweeter D27AG-45-06 (soft dome)
My first thoughts were that the balance between the woofer & tweeter is wrong.
Accordng to my calcs the attenuation of the tweeter in the circuit I used is around 2dB, so as you suggested this may need to be increased by varying R2 & R3?
best regards - ken
Full details of the tweeter D27AG-45-06 (soft dome)
My first thoughts were that the balance between the woofer & tweeter is wrong.
Accordng to my calcs the attenuation of the tweeter in the circuit I used is around 2dB, so as you suggested this may need to be increased by varying R2 & R3?
best regards - ken
the tone of your original post Ben was sarcastic and unhelpful. If you had have just said "if you could post some measurements it would remove a lot of the guesswork" It would have been a lot more palatable and acceptable. If you can't take it then don't dish it out!
Ken what do you have as source?
A computer maybe? If yes you could try to investigate FE3T suggestion: use a high shelf eq with freq of 115/ width of your cabinet in meter (eg width of 20cm: 115/0.2= 575hz )and attenuate of some db ( up to -6 max).
This will tell you if this is BSC related or not.
A computer maybe? If yes you could try to investigate FE3T suggestion: use a high shelf eq with freq of 115/ width of your cabinet in meter (eg width of 20cm: 115/0.2= 575hz )and attenuate of some db ( up to -6 max).
This will tell you if this is BSC related or not.
I really don't think we should need too much measuring to know what to do with the famous old Vifa P17WJ-00-08 woofer!
It's a flattish 6" polycone: Vifa 2-Way Loudspeaker System
I am still vague on the tweeter. Vifa D27AG-45-06 might be a 1" fabric dome around 92dB sensitivity. I don't know if it is ferrofluid.
As it goes, there aren't many published designs for this sort of combination, despite the P17WJ being one of the best polycones ever made. It is still in production.
Troels Gravesen discusses the P17WJ here in a sort of homage 6" plus 1" project:
18W-8434G00
Anyhoo. I thought I'd try Ken Clark's crossover with vaguely similar drivers. Below. It's not pretty really. The bass filter is 6dB/octave for 3kHz crossover. But bass light. The tweeter is wildly too loud, as expected.
It's not even an easy fix. 6" speakers aren't the easiest things to do, IMO. They seem to drive you to a low 2-2.5kHz crossover which may not suit a lot of tweeters. A successful 3kHz XO example of this sort of thing was the polycone Heybrook HB2, below.
I have been looking at some of my old modelling projects, and I have a few ideas that work quite well, but need to mull it over really. I did find that a much bigger bafflestep coil is needed here to knock the bass into shape. So we might be looking at a considerable redesign.
It's a flattish 6" polycone: Vifa 2-Way Loudspeaker System
I am still vague on the tweeter. Vifa D27AG-45-06 might be a 1" fabric dome around 92dB sensitivity. I don't know if it is ferrofluid.
As it goes, there aren't many published designs for this sort of combination, despite the P17WJ being one of the best polycones ever made. It is still in production.
Troels Gravesen discusses the P17WJ here in a sort of homage 6" plus 1" project:
18W-8434G00
Anyhoo. I thought I'd try Ken Clark's crossover with vaguely similar drivers. Below. It's not pretty really. The bass filter is 6dB/octave for 3kHz crossover. But bass light. The tweeter is wildly too loud, as expected.
It's not even an easy fix. 6" speakers aren't the easiest things to do, IMO. They seem to drive you to a low 2-2.5kHz crossover which may not suit a lot of tweeters. A successful 3kHz XO example of this sort of thing was the polycone Heybrook HB2, below.
I have been looking at some of my old modelling projects, and I have a few ideas that work quite well, but need to mull it over really. I did find that a much bigger bafflestep coil is needed here to knock the bass into shape. So we might be looking at a considerable redesign.
Attachments
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After re-vamping my high pass filter I experienced exactly the same symptons as you describe above. Fortunately, I had incorporated a variable L-pad control and was able to reduce the tweeter level by exactly the required amount to solve the problem. I agree that reducing the tweeter level should be the first 'fix' to try.
Thanks again Steve - I really appreciate your comments.
There is certainly a lot of difference between the complexity of the two circuits you sent.
Attached is a data sheet for the tweeter & also a photo of the finished enclosure (quarter wave transmission line, elliptical shape, cast concrete)
best regards
ken
There is certainly a lot of difference between the complexity of the two circuits you sent.
Attached is a data sheet for the tweeter & also a photo of the finished enclosure (quarter wave transmission line, elliptical shape, cast concrete)
best regards
ken
Attachments
Nice enclosure.
Nice enclosure. The crossover has no baffle step correction .66mh won't do it. Without measurements, it's still possible. Just takes more time.
You could add an ~1.5mh-2.0mh with a 3-6 ohm wirewound across it, placed behind the woofer crossover. Then pad the tweeter down with an ohm or 3 before the tweeter crossover.
Good choice of drivers for this. In the end, you could buy a Dayton Omnimic V2 from Theloudspeakerkit.com.au. Or Wagner.
Nice enclosure. The crossover has no baffle step correction .66mh won't do it. Without measurements, it's still possible. Just takes more time.
You could add an ~1.5mh-2.0mh with a 3-6 ohm wirewound across it, placed behind the woofer crossover. Then pad the tweeter down with an ohm or 3 before the tweeter crossover.
Good choice of drivers for this. In the end, you could buy a Dayton Omnimic V2 from Theloudspeakerkit.com.au. Or Wagner.
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