Allen,
I plan to add baffle step for my tabaq. I have 3 sets of baffle step to see which one I like best.
Yes, I should use a notch filter in the TABAQ but have no measurement tools so I can only guess looking at the frequency response provided by manufacturer. We will see if a notch is needed first.
I plan to add baffle step for my tabaq. I have 3 sets of baffle step to see which one I like best.
Yes, I should use a notch filter in the TABAQ but have no measurement tools so I can only guess looking at the frequency response provided by manufacturer. We will see if a notch is needed first.
Mr AllenB I am recovering from a Stroke I will be needing for some help. I thank you for your
advices you are a very special person. I have The Bill Waslo IMP w mlsa lately Ipurchased Dats from Part Express but I do not trast on the device(my IMP has the software corrupted and does not work no matter my efforts. so I would like (please) that you advise me a not costly but accurate and friendly Audio tester capable of deliver decent TS parameters and the usual features. Due to my Stroke I am now like a "newbie", As I am using windos / some software does not work well but if needed I would change the OS I thank you in advance all the help that you can give me With all my respect I salute you. My english is also degraded The stroke forces you to learn again many things God be with you Sincerely yours...
advices you are a very special person. I have The Bill Waslo IMP w mlsa lately Ipurchased Dats from Part Express but I do not trast on the device(my IMP has the software corrupted and does not work no matter my efforts. so I would like (please) that you advise me a not costly but accurate and friendly Audio tester capable of deliver decent TS parameters and the usual features. Due to my Stroke I am now like a "newbie", As I am using windos / some software does not work well but if needed I would change the OS I thank you in advance all the help that you can give me With all my respect I salute you. My english is also degraded The stroke forces you to learn again many things God be with you Sincerely yours...
Thiele Small parameters are sometimes different to the spec sheet that you get with the driver. This doesn't matter much when you build a closed box. Most ordinary box building can be done with the factory parameters.
If you want to measure them you can use a multimeter or oscilloscope and audio generator to make your own impedance plot. You can also use your computer, and impedance measuring is useful for the impedance file used by a crossover simulator.
A real time spectrum analyser (avaliable as software) will make a plot, then you can use that to calculate things such as the driver resonance. Start with a 10 ohm resistor in a voltage divider with a much larger value (maybe 1000 ohms), and adjust until you get a flat plot of say, 10mV across the 10 ohm resistor, depending on the noise of your card. Then swap the resistor for your driver.
If you want to measure them you can use a multimeter or oscilloscope and audio generator to make your own impedance plot. You can also use your computer, and impedance measuring is useful for the impedance file used by a crossover simulator.
A real time spectrum analyser (avaliable as software) will make a plot, then you can use that to calculate things such as the driver resonance. Start with a 10 ohm resistor in a voltage divider with a much larger value (maybe 1000 ohms), and adjust until you get a flat plot of say, 10mV across the 10 ohm resistor, depending on the noise of your card. Then swap the resistor for your driver.
I'm not sure, but I've seen manufacturing tolerance that is worse. The reason I'm not too concerned is that softening suspension increases compliance and hence the significance of a given closed volume, compensating the lower fs and Q in a feedback loop. Small Q variations can be equalised, and I'd expect to be making such adjustments at any rate.
i just bought behringer ecm8000 and phantom supply to help me on this never been good sounding 12" and horn on OB. changed R L C value, I even changed different amplifier and still get bad recessed mid, dull treble. at one point i'm tired of another iteration, remembered on this post
Practical tips loudspeaker DIY
quotes that I always remember
"you equalize and flatten the wrinkles and at the end everything just does not sound like music at all. We must LET THE MIDBASS PLAY. Not limit it, not flatten it, not use notch filters or any manipulation by XO. Let's make it play the way it plays. If you do not like the way it sounds "naked", please change it"
I take out all my 12dB xo LPF and HPF, then mid 12" has no filter at all, horn tweeter only use 3.3uf caps and now I'm done with this setup, the result as expected
lesson learning today, with good driver sometimes simple is better.
Practical tips loudspeaker DIY
quotes that I always remember
"you equalize and flatten the wrinkles and at the end everything just does not sound like music at all. We must LET THE MIDBASS PLAY. Not limit it, not flatten it, not use notch filters or any manipulation by XO. Let's make it play the way it plays. If you do not like the way it sounds "naked", please change it"
I take out all my 12dB xo LPF and HPF, then mid 12" has no filter at all, horn tweeter only use 3.3uf caps and now I'm done with this setup, the result as expected
lesson learning today, with good driver sometimes simple is better.
Experimentation helps...
I'm not sure this comment wasn't aimed at the baffle step.. a factor that you might find with OB and horn. The dispersion changes and the sound power in the room changes with respect to on-axis measurements. That is, the crossover changes depending on the dispersion, and the dispersion needs to be chosen to fit the application and to change smoothly and purposefully. This can only be confirmed by taking multiple measurements around the speaker and combining them.
I'm not sure this comment wasn't aimed at the baffle step.. a factor that you might find with OB and horn. The dispersion changes and the sound power in the room changes with respect to on-axis measurements. That is, the crossover changes depending on the dispersion, and the dispersion needs to be chosen to fit the application and to change smoothly and purposefully. This can only be confirmed by taking multiple measurements around the speaker and combining them.
Not exactly, my comment was referring to any inappropriate or sudden change in directivity.
If all goes well with your dipole you may end up with a region of falling response with a flat response above this. I've attached a random dipole response plot from S. Linkwitz's site.
You might want to use the speaker in the sloping region (otherwise why make a dipole) and one way to compensate for this is to begin your crossover in this region. This can bring it back to flat... then where the response is already flat higher up, it will pull it down and roll it off. This way, the crossover is set by the baffle dimensions.
If this is a woofer, then the lower you begin this low-pass crossover, the more low bass you'll get. On the other hand sensitivity will be lower and so will power handling.
You might want to use the speaker in the sloping region (otherwise why make a dipole
) and one way to compensate for this is to begin your crossover in this region. This can bring it back to flat... then where the response is already flat higher up, it will pull it down and roll it off. This way, the crossover is set by the baffle dimensions.If this is a woofer, then the lower you begin this low-pass crossover, the more low bass you'll get. On the other hand sensitivity will be lower and so will power handling.
Attachments
Thanks for the quick response.
I am following this article http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf. At the bottom of page 8 is the graph of a woofer eminence alpha15 but the graph of beta 15a is very similar, but with more 4Dbs. Taking the advice on using the crossover at 125hz, by my calculations the reel will be 5mh am I right?
I am following this article http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf. At the bottom of page 8 is the graph of a woofer eminence alpha15 but the graph of beta 15a is very similar, but with more 4Dbs. Taking the advice on using the crossover at 125hz, by my calculations the reel will be 5mh am I right?
sorry if this is ot.
pbr and laziness are in charge over here, apologies.
looking for an online calculator for single xover circuit elements,
this would be for what I think would be called parallel xovers, correct me if I'm wrong
hopefully, it would have x spaces for me to enter
first entry: choice of series element or shunt, highpass or lowpass
second: desired "knee" frequency, for dropoff of 6db/octave
above/below this single circuit element
(highpass for cap-series or inductor-shunt,
lowpass for inductor-series or cap-shunt)
third: impedence of "target" speaker, bare (no other xover elements), at that frequency
yes, something so simple would leave an absolute vaccuum,
despite nature's "abhorrent!" cry,
of how any other shunts/series elements would work together.
but it would be enough to give numbskulls like me a start at guessing rough magnitudes
of parts involved, and going to Digi-Key or some such & pricing such rough ideas out
(in at least a little tighter fashion than simply acknowledging
lower=more expensive, eventually nutso)
my lukewarm pabst thanks you for your patience
(and diligence if you got this far),
I'm just along for the ride, but thanks! for any reliable refs at all
pbr and laziness are in charge over here, apologies.
looking for an online calculator for single xover circuit elements,
this would be for what I think would be called parallel xovers, correct me if I'm wrong
hopefully, it would have x spaces for me to enter
first entry: choice of series element or shunt, highpass or lowpass
second: desired "knee" frequency, for dropoff of 6db/octave
above/below this single circuit element
(highpass for cap-series or inductor-shunt,
lowpass for inductor-series or cap-shunt)
third: impedence of "target" speaker, bare (no other xover elements), at that frequency
yes, something so simple would leave an absolute vaccuum,
despite nature's "abhorrent!" cry,
of how any other shunts/series elements would work together.
but it would be enough to give numbskulls like me a start at guessing rough magnitudes
of parts involved, and going to Digi-Key or some such & pricing such rough ideas out
(in at least a little tighter fashion than simply acknowledging
lower=more expensive, eventually nutso)
my lukewarm pabst thanks you for your patience
(and diligence if you got this far),
I'm just along for the ride, but thanks! for any reliable refs at all
There are many online calculators available. You can confirm that they should give the same result for a first order filter into a fixed resistance.
This is where the response is at -3dB, which is the half power point. Speakers are often crossed at -6dB which is the half pressure point. For this and other reasons the desired values may vary.
First order filters can be difficult to work with, especially where the speakers don't have a smooth/gradual natural response.
This is where the response is at -3dB, which is the half power point. Speakers are often crossed at -6dB which is the half pressure point. For this and other reasons the desired values may vary.
First order filters can be difficult to work with, especially where the speakers don't have a smooth/gradual natural response.
I have a pair of DIY loudspeakers with Dynaudio drivers. They were built in mid 80's. Recently my tweeter got fried and I finally managed to get a replacement. However, I think it would be good time to replace the capacitors. These boxes were custom built by a guy who is unfortunately no longer with us. I took out the crossover from one of the boxes, but I have hard time determining the values of two capacitors. I'm no electronic wiz, so if the value is not specifically stated in μF, I am not sure what they are. The only thing on one of them is:
MKT 1.60
10 K 160V-
It's a bigger thing, inch x inch x half an inch. I'd really appreciate any help.
MKT 1.60
10 K 160V-
It's a bigger thing, inch x inch x half an inch. I'd really appreciate any help.