Hello everyone, 
I am new to diy audio and have been researching and dreaming of speaker design for quite a while and now the time has come for me to make my first speaker and would love some help and answers from the diyaudio community. I have decided on a closed box, 2 way design to keep things nice and easy for my first attempt. I've decided on the drivers, the tweeter being a vifa XT25BG60-04 and a SB13PFC25-04 for the mid/sub I have attached the spec sheets below. My reasons for selecting these drivers was 1. Budget 2.i had heard good things about them mainly internet reviews and comments and 3. They seem a reasonable match for a crossover for a two way (at 2khz). as a newbie i would love to hear any opinions on this.
The main questions I have concerning the drivers is power ratings. The woofer is rated at 40w (rated power handling) and the tweeter is rated at 100w (rated noise power). Are these the same? And if so is the difference in the power rating a problem?.
The other power rating questions I have is to do with crossover components. I have designed the crossover and all its different values. But i'm a bit confused by the power rating of components like resistors etc. should the components be rated the same as the drivers eg: 40w for woofer and 100w for tweeter?. Or is it the same wattage for the whole crossover? Does anyone know of any guides for this?
Cheers everyone hope to hear from you all soon.
I am new to diy audio and have been researching and dreaming of speaker design for quite a while and now the time has come for me to make my first speaker and would love some help and answers from the diyaudio community. I have decided on a closed box, 2 way design to keep things nice and easy for my first attempt. I've decided on the drivers, the tweeter being a vifa XT25BG60-04 and a SB13PFC25-04 for the mid/sub I have attached the spec sheets below. My reasons for selecting these drivers was 1. Budget 2.i had heard good things about them mainly internet reviews and comments and 3. They seem a reasonable match for a crossover for a two way (at 2khz). as a newbie i would love to hear any opinions on this.
The main questions I have concerning the drivers is power ratings. The woofer is rated at 40w (rated power handling) and the tweeter is rated at 100w (rated noise power). Are these the same? And if so is the difference in the power rating a problem?.
The other power rating questions I have is to do with crossover components. I have designed the crossover and all its different values. But i'm a bit confused by the power rating of components like resistors etc. should the components be rated the same as the drivers eg: 40w for woofer and 100w for tweeter?. Or is it the same wattage for the whole crossover? Does anyone know of any guides for this?
Cheers everyone hope to hear from you all soon.
Welcome to the forum! That looks like a good first project, although I would pick a bigger woofer. 🙂
Don't worry about those power ratings, they won't come into play with this speaker or crossover. How have you designed your crossover? Are you doing it by hand or with simulation software? There is some very good free software available that people here would by glad to help you with.
Don't worry about those power ratings, they won't come into play with this speaker or crossover. How have you designed your crossover? Are you doing it by hand or with simulation software? There is some very good free software available that people here would by glad to help you with.
10W ceramic resistors are adequate for the majority of domestic loudspeaker crossovers.
thanks for the replies.
i am using a no measurement method described in this post. Introduction to designing crossovers without measurement im using it because it made sense to me and it seemed like a good starting point. i am also reading through Vance dickasons loudspeaker design cookbook. i am however very interested in learning some software, are there any you would recommend?
also concerning a bigger woofer. i have looked at larger woofers but struggling to find one that would cross over as well. are there any particular woofers or size of woofer you would recommend for a 2 way?
also a question for Galu. is there any disadvantage to over doing it on the wattage in terms of sound quality? say if i went for 20w
cheers.
i am using a no measurement method described in this post. Introduction to designing crossovers without measurement im using it because it made sense to me and it seemed like a good starting point. i am also reading through Vance dickasons loudspeaker design cookbook. i am however very interested in learning some software, are there any you would recommend?
also concerning a bigger woofer. i have looked at larger woofers but struggling to find one that would cross over as well. are there any particular woofers or size of woofer you would recommend for a 2 way?
also a question for Galu. is there any disadvantage to over doing it on the wattage in terms of sound quality? say if i went for 20w
cheers.
I remember reading Vance Dickason. Lots of interesting things there. When you feel ready for it you could look at XSim software, written by a member here.
What would you say is the limiting factor?
20W for a resistor in front of that tweeter isn't needed. 10W is plenty.
Most of my listening to small speakers is usually at 10 watts or less and the tweeter only sees a small percentage of that. Resistors are generally regarded as being benign as far as SQ goes. Of course if you already have 20W rated resistors use them but don't buy them thinking they will be any better for such a small driver.
Most of my listening to small speakers is usually at 10 watts or less and the tweeter only sees a small percentage of that. Resistors are generally regarded as being benign as far as SQ goes. Of course if you already have 20W rated resistors use them but don't buy them thinking they will be any better for such a small driver.
Ran the numbers for your lil' five incher...
Internal box volume, (Vb) Ten liters
Tuned frequency for enclosure (fb) 57 hertz
Low end cutoff @ 3Db down,(F3), 53.55 Hertz @ -3.03 Db.
Port inner diameter, 47 mm, by 123 mm long
Running this driver sealed up will make for poor performance on the bottom end....besides, the simulator calculates for EBP, Efficiency Bandwidth Product & makes the selection for either sealed or ported....and your driver choice is firmly in the ported camp.
-------------------------------------------------------------------Rick........
Internal box volume, (Vb) Ten liters
Tuned frequency for enclosure (fb) 57 hertz
Low end cutoff @ 3Db down,(F3), 53.55 Hertz @ -3.03 Db.
Port inner diameter, 47 mm, by 123 mm long
Running this driver sealed up will make for poor performance on the bottom end....besides, the simulator calculates for EBP, Efficiency Bandwidth Product & makes the selection for either sealed or ported....and your driver choice is firmly in the ported camp.
-------------------------------------------------------------------Rick........
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Pano,
Funny, at 100 Hz, the woofer's excursion could outrun the tweeter's at 2kHz by about 8dB. Note the woofer's linear excursion is 9mm peak to peak, 4.5mm Xmax, one way linear excursion.
At 45Hz, the woofer would run out of gas at 86 dB at one meter, the tweeter 91 dB. I can comfortably play my acoustic guitar and sing at that level.
This is an interesting tweeter- runs out of linear excursion (Xmax) at just under 1 watt, but won't burn up till 100 watts (500Hz-20kHz).
Good first project- the tweeter should sound terrible well before it lets out the magic smoke ;^).
Art
Attachments
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The travel, energy, of the woofer will transfer to the port & enclosure at its resonance frequency.
--------------------------------------------------------------------------Rick......
--------------------------------------------------------------------------Rick......
Getting back to the original question.
I seem to recall that the tweeter power handling is total system power including a suitable Crossover, usually second order at twice the tweeters resonance frequency.
I seem to recall that the tweeter power handling is total system power including a suitable Crossover, usually second order at twice the tweeters resonance frequency.
it seemed to me that most of response curves for the 7" and 8" drivers i looked at start to get rather wiggly around the 1khz region. i believe this indicates cone breakup or at least would make the crossover more noticeable / difficult to design is this correct? ive also struggled to find a tweeter that would cross that low if i am trying to stay two octaves above Fs. do you think it would be safe for this tweeter to cross at 1khz?
cheers.
also
tank you man how did you calculate theese figures? i would like to try for myself.
sorry most of this has gone over my head could you maybe explain in layman's terms.
the tweeter is a ring radiator and the effective cone diameter is 3.24cm. dont no is this effects the xmax issue ?
tank you man how did you calculate theese figures? i would like to try for myself.
sorry most of this has gone over my head could you maybe explain in layman's terms.
the tweeter is a ring radiator and the effective cone diameter is 3.24cm. dont no is this effects the xmax issue ?
A budget driver needs to have some shortcomings... this one won't go low enough, but probably it will provide a reasonable output. A 2KHz crossover point is fine, maybe you can even go a bit higher, but a simulation is needed in order to see what happens with the breakup.
A 7-8L box tuned to 50Hz will provide reasonable bass output (-6dB point in the mid 40s), and the driver will exceed xmax at some 25W in the low 40s with this tuning. I'd say this is the best you can reach with this driver. And with this input also 5W resistors should be safe, 10W would be for your peace of mind.
Ralf
What I really dislike in this woofer is the non round shape.
A 7-8L box tuned to 50Hz will provide reasonable bass output (-6dB point in the mid 40s), and the driver will exceed xmax at some 25W in the low 40s with this tuning. I'd say this is the best you can reach with this driver. And with this input also 5W resistors should be safe, 10W would be for your peace of mind.
Download Unibox and play with it.
No.
Ralf
What I really dislike in this woofer is the non round shape.
Jack, a 7" or 8" driver shouldn't be breaking up at 1k, even 2k. Given that they should be pistonic sometimes a well placed crossover wiggle can be used to fit the gap and make things straight.
Usually a 6.5” driver breaks at 4+ KHz, but IMHO they are almost difficult to work with in a simple 2-way for a novice, unless using some well behaved drivers (some polypropylene cone ones). A 5” driver is easier.
Ralf
Ralf
Maybe its terminology.
Where the differing angular frequency response traces start to diverge is a function of the diameter of the cone causing beaming to start, it can be around 2k or so for a smaller 13cm driver. Break up as others say shouldn't occur as low as that, typically past 3-5Khz
I know you want to try designing by listening, nothing wrong with that at all. But it can take time, be frustrating and if you interpret something wrongly you can end up trying to fix the wrong element of the design.
Interestingly not quite the same driver line up you propose is used in a 6 part YouTube series.
Look for Impulse audio and his Life S5 design. it should help answer a few more questions. here is a link to part 2A
YouTube
In one of the parts of the series it introduces Xsim which is a very useful tool that with a bit of patience can be used to verify lots of stuff.
Maybe watch the videos.
Then do you own thing and keep asking more questions and keep us updated with your thoughts on the sound of your design as you progress.
Where the differing angular frequency response traces start to diverge is a function of the diameter of the cone causing beaming to start, it can be around 2k or so for a smaller 13cm driver. Break up as others say shouldn't occur as low as that, typically past 3-5Khz
I know you want to try designing by listening, nothing wrong with that at all. But it can take time, be frustrating and if you interpret something wrongly you can end up trying to fix the wrong element of the design.
Interestingly not quite the same driver line up you propose is used in a 6 part YouTube series.
Look for Impulse audio and his Life S5 design. it should help answer a few more questions. here is a link to part 2A
YouTube
In one of the parts of the series it introduces Xsim which is a very useful tool that with a bit of patience can be used to verify lots of stuff.
Maybe watch the videos.
Then do you own thing and keep asking more questions and keep us updated with your thoughts on the sound of your design as you progress.
Hello everyone, thanks for all the advice.
I am aware of this channel it was where i herd of this woofer when i was researching drivers for this project. Its actually his number one woofer in his top three midwoofer/woofer video. Ill stick a link in YouTube . its because of his glowing review and its price i chose to use this driver. I'll definitely check out the series you mentioned. I'm sure itll be very helpful thanks for the tip off.
My main reason for going down this route was because i didn't really want to buy measuring equipment until i got a feel for it. But i have checked out Xsim and it looks pretty nifty. Does anyone know if it is possible to use it without doing your own measurements.
I think i'll stick with this woofer for the time being until i have become comfortable with crossover design. With the intention of either swapping out the woofer or adding one to make a 3 way when i'm a bit more knowledgeable.
I am aware of this channel it was where i herd of this woofer when i was researching drivers for this project. Its actually his number one woofer in his top three midwoofer/woofer video. Ill stick a link in YouTube . its because of his glowing review and its price i chose to use this driver. I'll definitely check out the series you mentioned. I'm sure itll be very helpful thanks for the tip off.
My main reason for going down this route was because i didn't really want to buy measuring equipment until i got a feel for it. But i have checked out Xsim and it looks pretty nifty. Does anyone know if it is possible to use it without doing your own measurements.
I think i'll stick with this woofer for the time being until i have become comfortable with crossover design. With the intention of either swapping out the woofer or adding one to make a 3 way when i'm a bit more knowledgeable.
Ok.
That seems a very sensible approach.
If you look at the impulse videos I think he has provided links to the files that are needed by XSim. The .frd and .zma files.
It is possible to use XSim without doing your own measurements, but you will need to trace the manufacturers frequency and impedance data of the drivers you want to uses so as to make the .frd and .zma files for that driver.
More and more posts here have the relevant files attached so once you have downloaded XSim you will be able to play with their data too to help you gain more knowledge.
An important point to remember is manufacturers data does not account for Diffraction loss or Baffle step, so you may actually use more inductance or the bass mid to get a flat response in a room. It is a subtle adjustment and can be overdone, it also depends on speaker positioning in a room, so you have to make that as a design decision. If the speakers are crammed into a corner you may not need it.
That seems a very sensible approach.
If you look at the impulse videos I think he has provided links to the files that are needed by XSim. The .frd and .zma files.
It is possible to use XSim without doing your own measurements, but you will need to trace the manufacturers frequency and impedance data of the drivers you want to uses so as to make the .frd and .zma files for that driver.
More and more posts here have the relevant files attached so once you have downloaded XSim you will be able to play with their data too to help you gain more knowledge.
An important point to remember is manufacturers data does not account for Diffraction loss or Baffle step, so you may actually use more inductance or the bass mid to get a flat response in a room. It is a subtle adjustment and can be overdone, it also depends on speaker positioning in a room, so you have to make that as a design decision. If the speakers are crammed into a corner you may not need it.
I've used XSim on about a dozen speaker rebuilds. If I can get the factory data for the drivers (like from Parts Express) I will use it at least as a starting point.
What I find is that it gets you pretty darned close... but seldom gets it exactly right. So some measuring is necessary after the fact to adjust for any large anomalies.
One thing I've learned over the years... room placement of the speakers will do more for you than the best freaking crossover on the planet. Speakers are pretty blunt instruments that both affect their surroundings and are affected by them. Before I dump a couple of hundred on crossover parts, I'm going to try small adjustments to the speaker positions.
success! he has provided all that is needed hes even provided measurements for baffle placement so i hope that some elements of diffraction and baffle step are are accounted for in the measurements. thanks again for the guidance raymondo ill get craking on Xsim in the next day or two.
as for speaker placement its most likely going to be in a corner on my desk. what kind of considerations should i be aware off when designing the speaker?
thanks again for everyone's help!
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