This is a pretty amateur question, but I couldn't find the answer I was exactly looking for. I think I have a handle on it, but I'm not quite sure, so here goes:
I understand that the F3 variable represents the -3dB half power frequency, which indicates the beginning of low end roll off. I'm looking to set up my first pair of multi-way speakers, and I'm trying to set up a two-way system (I'd rather not try to crossover three drivers on my first go-around) so I'm trying to figure out the recommended frequency response for this driver.
https://www.madisound.com/store/product_info.php?cPath=45_228_257&products_id=8772
The F3 in a sealed system with an enclosure around .85 cubic feet would be 59 Hz, correct? Additionally, would the total Q of the woofer at Fs be .34? I'm still trying to get all the nomenclature down, but I'm obviously having a hard time. I'm trying to build a speaker system with a Qts of around .90, .95, for a warmer sound. Am I on the right track?
That said, I'm trying to read this frequency response graph and trying to deduce where it rolls off.
I'm thinking it rolls off at around 1.5kHz? I'm probably reading the log scale wrong. Would this make the recommended frequency range 20Hz - 1500Hz? I'm not very confident in my results, any help would be greatly appreciated.
Also, on a separate note, for a two-way speaker, would this be an appropriate woofer? Any recommendations for a tweeter? Thanks for putting up with the inane questions, I'm just having a hard time figuring it all out.
I understand that the F3 variable represents the -3dB half power frequency, which indicates the beginning of low end roll off. I'm looking to set up my first pair of multi-way speakers, and I'm trying to set up a two-way system (I'd rather not try to crossover three drivers on my first go-around) so I'm trying to figure out the recommended frequency response for this driver.
https://www.madisound.com/store/product_info.php?cPath=45_228_257&products_id=8772
The F3 in a sealed system with an enclosure around .85 cubic feet would be 59 Hz, correct? Additionally, would the total Q of the woofer at Fs be .34? I'm still trying to get all the nomenclature down, but I'm obviously having a hard time. I'm trying to build a speaker system with a Qts of around .90, .95, for a warmer sound. Am I on the right track?
That said, I'm trying to read this frequency response graph and trying to deduce where it rolls off.
An externally hosted image should be here but it was not working when we last tested it.
I'm thinking it rolls off at around 1.5kHz? I'm probably reading the log scale wrong. Would this make the recommended frequency range 20Hz - 1500Hz? I'm not very confident in my results, any help would be greatly appreciated.
Also, on a separate note, for a two-way speaker, would this be an appropriate woofer? Any recommendations for a tweeter? Thanks for putting up with the inane questions, I'm just having a hard time figuring it all out.
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Hi,
Qts relates to the drive unit total system not the driver and box combination. I imagine that the 0.85 cubic feet box will be a butter worth alignment which means it will have a Q of approximately 0.7.
To increase the Q you need to make the box smaller this will rase Fs from 59Hz but will increase the peak in the response before roll off. To simualte this download the Linearteam tool shown below
If you want a warm mid bass it would probably be better to do this using baffle step compensation in the crossover. (Search for BSC on this site for lots of details)
This speakers response would be from arround 60Hz to 5KHz in the 0.85 cubic foot box on axis (however the off axis response falls away quickly ay 5KHz as shown by the green and red traces. (A simulation would confirm this for th bass response) If you want lower bass with a single 8 inch driver you will need to use a port but it will still only get you down to about 40Hz I would think. To achive 20Hz with a single 8 inch driver would require very large excursions of the driver and probably active bass equalisation.
This driver should probably be crossed over at about 1.5KHz for a good off axis response. Not many tweeters are happy down to 1.5KHz so you may want to choose a 6 inch driver for your first design as this will be much easier to get a tweeter to work with.
From another thread I posted in in some helpfull links, the linear team link will alow you to simulate the Q of the system in any size box. Do read the help and follow it exactly when entering your drivers parameters:
LinearTeam
Good free box design program (you need the T-S parameters from the speaker you want to use) Follow the help exactly to enter the parameters or it will not allow you to complete the entry.
Speaker Workshop Download
Probably the best free speaker design package but it is evil to learn how to use.
Speaker Workshop Tutorial
one of several tutorial on how to use it (search the web for others)
HOLM Acoustics
Probably the best free measurement software and fairly easy to use. You will need a microphone and a half decent sound card but that is all.
FRD Consortium
Collection of very usefull simulation tools mostly in Excell. Th Baffle Step compenation program is really good for demonstrating how just moving a drive unit a few cm in a cabinet can significantly affect the frequency response.
John Conover: Using the Panasonic WM61A as a Measurement Microphone
How to build a really cheap but flatish response microphone for only a few £ or $. If you only take one peice of advice from me it would be don't try to build speakers without a microphone. It would be like setting sail without even a compass, you can use the sun but its not really that much help unless you have years of experience, your ears are much the same.
Regards,
Andy
Qts relates to the drive unit total system not the driver and box combination. I imagine that the 0.85 cubic feet box will be a butter worth alignment which means it will have a Q of approximately 0.7.
To increase the Q you need to make the box smaller this will rase Fs from 59Hz but will increase the peak in the response before roll off. To simualte this download the Linearteam tool shown below
If you want a warm mid bass it would probably be better to do this using baffle step compensation in the crossover. (Search for BSC on this site for lots of details)
This speakers response would be from arround 60Hz to 5KHz in the 0.85 cubic foot box on axis (however the off axis response falls away quickly ay 5KHz as shown by the green and red traces. (A simulation would confirm this for th bass response) If you want lower bass with a single 8 inch driver you will need to use a port but it will still only get you down to about 40Hz I would think. To achive 20Hz with a single 8 inch driver would require very large excursions of the driver and probably active bass equalisation.
This driver should probably be crossed over at about 1.5KHz for a good off axis response. Not many tweeters are happy down to 1.5KHz so you may want to choose a 6 inch driver for your first design as this will be much easier to get a tweeter to work with.
From another thread I posted in in some helpfull links, the linear team link will alow you to simulate the Q of the system in any size box. Do read the help and follow it exactly when entering your drivers parameters:
LinearTeam
Good free box design program (you need the T-S parameters from the speaker you want to use) Follow the help exactly to enter the parameters or it will not allow you to complete the entry.
Speaker Workshop Download
Probably the best free speaker design package but it is evil to learn how to use.
Speaker Workshop Tutorial
one of several tutorial on how to use it (search the web for others)
HOLM Acoustics
Probably the best free measurement software and fairly easy to use. You will need a microphone and a half decent sound card but that is all.
FRD Consortium
Collection of very usefull simulation tools mostly in Excell. Th Baffle Step compenation program is really good for demonstrating how just moving a drive unit a few cm in a cabinet can significantly affect the frequency response.
John Conover: Using the Panasonic WM61A as a Measurement Microphone
How to build a really cheap but flatish response microphone for only a few £ or $. If you only take one peice of advice from me it would be don't try to build speakers without a microphone. It would be like setting sail without even a compass, you can use the sun but its not really that much help unless you have years of experience, your ears are much the same.
Regards,
Andy
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I actually own a copy of LspCAD Pro v6 I just have no idea how to use it. A friend passed it on to me. I've tried going through the manual but I'm utterly lost.
As far as microphones go, however, I actually have a decent cardioid reference microphone that does a good job at giving a flat response. I typically use it for recording in studio, but it should do the trick.
Would crossing over a three-way speaker be much harder? I'd rather not go down to a 6 inch if I don't have to. I was looking forward to putting together a larger speaker, sort of in the spirit of an early Acoustic Research but with modern dynamics, if that makes any sense.
If I went with a 10" or an 8" woofer, would I have to go three way to make a decent set of speakers or is it possible to find a tweeter that could come down that low.
https://www.madisound.com/store/product_info.php?cPath=45_229_324&products_id=8497
Something like that maybe?
As far as microphones go, however, I actually have a decent cardioid reference microphone that does a good job at giving a flat response. I typically use it for recording in studio, but it should do the trick.
Would crossing over a three-way speaker be much harder? I'd rather not go down to a 6 inch if I don't have to. I was looking forward to putting together a larger speaker, sort of in the spirit of an early Acoustic Research but with modern dynamics, if that makes any sense.
If I went with a 10" or an 8" woofer, would I have to go three way to make a decent set of speakers or is it possible to find a tweeter that could come down that low.
https://www.madisound.com/store/product_info.php?cPath=45_229_324&products_id=8497
Something like that maybe?
You may want to rethink that design choice...
First off, 8" 2-ways can be rather difficult, unless you use drivers that are very well behaved, and have an extended frequency response.
A 10" 2-way is virtually inconceivable, unless you find a rare-bird. I think the only ones I know that might do that are the Morel 1075 and the Dayton DC300. BUT- you have to have a tweeter that is equally capable of that task. It will have to reach to 1.2kHz or lower, and that is a tough load to haul. Most 'robust' tweeters are good to about 1.8 kHz, LR4 acoustic.
All that said- your 8" you chose looks like it could be fairly benign. Using the right coil/cap to round off the short rise from 1-3 kHz might fare you very well. The thing with 8" woofers, is that they really are only good to about 1.5 kHz before they start beaming. The problem with xovering this low is that the tweeter may require a slope to get there. You won't be doing it wih 12dB electrical filters. I suspect a 4th electrical is a must on the tweeter, and you will require a term of playing on the system to get it tuned in right. The power response and off-axis issues on an 8" 2-way are more difficult to dial in than anything smaller.
However- if you get it right, the soundstage will be massive, and they will have a very large sound.
While I know this is a metal woofer, this will give you an idea what I went through to get this one right:
MAX pictures by wolf_teeth_speaker - Photobucket
If you value your sanity 🙂gnasher🙂, don't use a metal woofer in an 8" 2-way....
Later,
Wolf
First off, 8" 2-ways can be rather difficult, unless you use drivers that are very well behaved, and have an extended frequency response.
A 10" 2-way is virtually inconceivable, unless you find a rare-bird. I think the only ones I know that might do that are the Morel 1075 and the Dayton DC300. BUT- you have to have a tweeter that is equally capable of that task. It will have to reach to 1.2kHz or lower, and that is a tough load to haul. Most 'robust' tweeters are good to about 1.8 kHz, LR4 acoustic.
All that said- your 8" you chose looks like it could be fairly benign. Using the right coil/cap to round off the short rise from 1-3 kHz might fare you very well. The thing with 8" woofers, is that they really are only good to about 1.5 kHz before they start beaming. The problem with xovering this low is that the tweeter may require a slope to get there. You won't be doing it wih 12dB electrical filters. I suspect a 4th electrical is a must on the tweeter, and you will require a term of playing on the system to get it tuned in right. The power response and off-axis issues on an 8" 2-way are more difficult to dial in than anything smaller.
However- if you get it right, the soundstage will be massive, and they will have a very large sound.
While I know this is a metal woofer, this will give you an idea what I went through to get this one right:
MAX pictures by wolf_teeth_speaker - Photobucket
If you value your sanity 🙂gnasher🙂, don't use a metal woofer in an 8" 2-way....
Later,
Wolf
Hi,
Just bide your time and wait for someone to publish a decent design.
it seems a good unit and someone will at some point, likely with a
well matching tweeter, keep checking the various design forums.
Keep searching on the driver number for information.
😎 /Sreten.
Just bide your time and wait for someone to publish a decent design.
it seems a good unit and someone will at some point, likely with a
well matching tweeter, keep checking the various design forums.
Keep searching on the driver number for information.
😎 /Sreten.
Well, I'm realizing now that this is going to be a tougher undertaking than I originally though (when is it not?) I think I'm still going to try for a 8" two-way. I think you guys have noted that it would take a bit of experimenting, but I'm up for it.
I've been searching for the past couple of hours for a decent combo, but I'm still stumbling around in the dark, it feels like. I'm excited about the possible result, however. I may end up just moving down to a 6" woofer for my first actual design if this proves too complex, but I'm going to jump in feet first.
I saw another Woofer that caught my eye, it goes a bit lower and has a decent frequency range all together.
https://www.madisound.com/store/product_info.php?cPath=45_228_257&products_id=1600
The tweeter: https://www.madisound.com/store/product_info.php?cPath=45_229_324&products_id=288
It has a frequency response from 800Hz to 30kHz. I think I could cross it over at around 1.5kHz. I could be wrong, in fact, I probably am.
I've been searching for the past couple of hours for a decent combo, but I'm still stumbling around in the dark, it feels like. I'm excited about the possible result, however. I may end up just moving down to a 6" woofer for my first actual design if this proves too complex, but I'm going to jump in feet first.
I saw another Woofer that caught my eye, it goes a bit lower and has a decent frequency range all together.
An externally hosted image should be here but it was not working when we last tested it.
https://www.madisound.com/store/product_info.php?cPath=45_228_257&products_id=1600
The tweeter: https://www.madisound.com/store/product_info.php?cPath=45_229_324&products_id=288
It has a frequency response from 800Hz to 30kHz. I think I could cross it over at around 1.5kHz. I could be wrong, in fact, I probably am.
Hi,
You cannot just pick drivers based on limited paper specifications.
Find an established design with drivers you like or the approach appeals.
Take a look at Zaph|Audio
😎 /sreten.
You cannot just pick drivers based on limited paper specifications.
Find an established design with drivers you like or the approach appeals.
Take a look at Zaph|Audio
😎 /sreten.
I'm familiar with Zaph, though, I'm a bit curious. What specifications are required when picking out drivers? I understand the designs he has are far superior than anything I could come up with, but what information do I need to understand before I can start putting together my own -- because honestly, that's why I love audio. The customization that is individual to me, something I chose.
I'm inclined to shy away from templates someone else made, and I'd like to understand the concepts behind choosing drivers that would complement each other. I don't just want to get the ingredients and make something without understanding the process behind the design and production of it. I'm not under the influence that their quality is poor or anything of the such, I'd just like to design something myself.
All that said, what specifications do I need to understand to start putting together my own? I've been brushing up my math skills to try to get through Loudspeaker Design Cookbook and understand it, and I have been for the most part. If you could give me some advice in regards to picking drivers, I'd greatly appreciate it. Thanks!
I'm inclined to shy away from templates someone else made, and I'd like to understand the concepts behind choosing drivers that would complement each other. I don't just want to get the ingredients and make something without understanding the process behind the design and production of it. I'm not under the influence that their quality is poor or anything of the such, I'd just like to design something myself.
All that said, what specifications do I need to understand to start putting together my own? I've been brushing up my math skills to try to get through Loudspeaker Design Cookbook and understand it, and I have been for the most part. If you could give me some advice in regards to picking drivers, I'd greatly appreciate it. Thanks!
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Unibox is good tool to download (free) and easy to use, to show how a driver will interact with box size/tuning (needs Excel); the parameters you need to input into Unibox are the ones you need to know about.
At the high end, you need to concentrate on the impedance curve to give you the impedance values to use in your calculations, and the freq response curve to help choose the xover point (the off axis curves are a good clue)
The SEAS driver you have chosen will probably be easier to xover because of the cone material; I’d consider using a SEAS tweeter too, these have a very good rep.
At the high end, you need to concentrate on the impedance curve to give you the impedance values to use in your calculations, and the freq response curve to help choose the xover point (the off axis curves are a good clue)
The SEAS driver you have chosen will probably be easier to xover because of the cone material; I’d consider using a SEAS tweeter too, these have a very good rep.
Thanks for the information.
https://www.madisound.com/store/product_info.php?cPath=45_229_324&products_id=778
Are you talking about something like that? From what I understand, the underhung voice coil (1.5 mm) will make it easier to xover, correct?
https://www.madisound.com/store/product_info.php?cPath=45_229_324&products_id=778
Are you talking about something like that? From what I understand, the underhung voice coil (1.5 mm) will make it easier to xover, correct?
Also, I'm not sure if I'm using Unibox right. This is the closed box graph I came up with, and I don't think it looks right. Perhaps I put the information in wrong.
Used this as the value: https://www.madisound.com/store/product_info.php?cPath=45_228_257&products_id=1600
Here's what I added. I also made my desired Qtc .90, I don't know if that's what it should be. Thanks for your help.
Drive Unit Parameters SEAS Prestige CA22RNX
Fs 29.00 Hz
Re 6.10 Ohm
Qms 2.04
Qes 0.52
Sd 230.0 cm2
Vas 97.0 l
Xmax peak 6.00 mm (Dunno if this is right or not, I took the voice coil height and subtracted it from the air gap height and divided by two)
(Le) 1.00 mH
(Le2) 0.00 mH
(Re2) 0.00 Ohm
Nominal Power 250.0 W (This is what I'm most concerned about, I took the short term power handling as the value)
External Components (I didn't know what to put in this section at all, so I left it alone)
Rs 0.20 Ohm
(Lco1) 0.00 mH
(Rco1) 0.00 Ohm
(Cco1) 0.00 uF
(Lco2) 0.00 mH
(Rco2) 0.00 Ohm
(Cco2) 0.00 uF
Everything else, other than what I mentioned I left the same. I dont think this accounts for the tweeter either.
For a desired Qtc of .9, I get a Vb of 20.9l and a physical Vb of 14.2l. Does that make sense?
Used this as the value: https://www.madisound.com/store/product_info.php?cPath=45_228_257&products_id=1600
An externally hosted image should be here but it was not working when we last tested it.
Here's what I added. I also made my desired Qtc .90, I don't know if that's what it should be. Thanks for your help.
Drive Unit Parameters SEAS Prestige CA22RNX
Fs 29.00 Hz
Re 6.10 Ohm
Qms 2.04
Qes 0.52
Sd 230.0 cm2
Vas 97.0 l
Xmax peak 6.00 mm (Dunno if this is right or not, I took the voice coil height and subtracted it from the air gap height and divided by two)
(Le) 1.00 mH
(Le2) 0.00 mH
(Re2) 0.00 Ohm
Nominal Power 250.0 W (This is what I'm most concerned about, I took the short term power handling as the value)
External Components (I didn't know what to put in this section at all, so I left it alone)
Rs 0.20 Ohm
(Lco1) 0.00 mH
(Rco1) 0.00 Ohm
(Cco1) 0.00 uF
(Lco2) 0.00 mH
(Rco2) 0.00 Ohm
(Cco2) 0.00 uF
Everything else, other than what I mentioned I left the same. I dont think this accounts for the tweeter either.
For a desired Qtc of .9, I get a Vb of 20.9l and a physical Vb of 14.2l. Does that make sense?
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Hi Zafsk,
I also decided to go it alone for my first "real" project, so I understand completely where you are coming from 🙂
things to look for that should make your life easier when choosing drivers (all in my oppinion of course).
* look for drivers with relatively tame breakup the smoother the rollof the better (try to find measurements that someone other than the manufacturer has done!)
* try and find drivers that are capable of playing an octave either side of your planned crossover freq. not necessarily an easy task! again manufacturers curves may mislead you here.
* try and match the drivers for sensitivity. Eg dont try and mate a 96db tweeter with an 86db woofer 😉 If you run two woofers in parallel you might be able to add up to a theorectical 6db to the sensitivity, but make sure they are 8 ohm woofers if you go down this path (note the woofers Re if it is 6 ohms or less you will possibly have trouble paralelling them).
* whilst it is somewhat out of date (won't necessarily have any recent drivers) have a look at the LDSG site LDSG Section 1 it should give you some ideas 🙂
* read and read and read, run simulations and also experiment with some real stuff! even if you just go out and buy some $15 drivers and measure them it will give you more confidence when it comes to spending some decent money 🙂
* don't hesitate to ask questions (you have already shown this isn't an issue)
there are probably many many more, but that will do for starters 🙂
Tony.
I also decided to go it alone for my first "real" project, so I understand completely where you are coming from 🙂
things to look for that should make your life easier when choosing drivers (all in my oppinion of course).
* look for drivers with relatively tame breakup the smoother the rollof the better (try to find measurements that someone other than the manufacturer has done!)
* try and find drivers that are capable of playing an octave either side of your planned crossover freq. not necessarily an easy task! again manufacturers curves may mislead you here.
* try and match the drivers for sensitivity. Eg dont try and mate a 96db tweeter with an 86db woofer 😉 If you run two woofers in parallel you might be able to add up to a theorectical 6db to the sensitivity, but make sure they are 8 ohm woofers if you go down this path (note the woofers Re if it is 6 ohms or less you will possibly have trouble paralelling them).
* whilst it is somewhat out of date (won't necessarily have any recent drivers) have a look at the LDSG site LDSG Section 1 it should give you some ideas 🙂
* read and read and read, run simulations and also experiment with some real stuff! even if you just go out and buy some $15 drivers and measure them it will give you more confidence when it comes to spending some decent money 🙂
* don't hesitate to ask questions (you have already shown this isn't an issue)
there are probably many many more, but that will do for starters 🙂
Tony.
Hi,
So your not realy familiar with Zaphs site at all, as it pretty much explains
everything ! (Albeit from Zaphs perspective and no-one elses.)
The best way to learn about design is from good examples, if you want to
also work out what is good design for yourself via a threads I'll leave you
to it, you can learn far more by researching good sites than you ever will
in a thread, thread answers are always far too short for the full story.
Interesting design : http://speakerdesignworks.com/Maverick_1.html
😎 /Sreten.
undefinition: Paul Carmody's DIY Audio Projects
Zaph|Audio
RJB Audio Projects
http://speakerdesignworks.com/
HTGuide Forum - powered by vBulletin
Humble Homemade Hifi
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
Linkwitz Lab - Loudspeaker Design
http://www.musicanddesign.com/
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Hi,
Your simulation looks plausible. A roll of at arround 60Hz is about what I woudl expect.
If you want to stick with the Seas 8 inch drive unit you could consider the following tweeters that both have low Fs so could be crossed over at arround 1.5KHz with a 4th order L-R filters and still achieve good SPL before excursion became a problem.
DX25TG09-04 - Vifa 1 inch dome tweeter fabric diaphragm high sensitivity - Europe Audio
E0006 - Seas Excel T25CF001 1 inch tweeter fabric dome - Europe Audio
The Vifa part is good value and for a first design it would be my choice.
Regards,
Andrew
Your simulation looks plausible. A roll of at arround 60Hz is about what I woudl expect.
If you want to stick with the Seas 8 inch drive unit you could consider the following tweeters that both have low Fs so could be crossed over at arround 1.5KHz with a 4th order L-R filters and still achieve good SPL before excursion became a problem.
DX25TG09-04 - Vifa 1 inch dome tweeter fabric diaphragm high sensitivity - Europe Audio
E0006 - Seas Excel T25CF001 1 inch tweeter fabric dome - Europe Audio
The Vifa part is good value and for a first design it would be my choice.
Regards,
Andrew
Ah, I wasn't sure if I did it right, glad to know it looks correct.
Thanks for the suggestion. I think I will use the Vifa. I guess it's now time to get to designing the enclosure and crossover. I know it says 20.9 liters for the volume, but is there a preferred way to distribute the cabinet as far as dimensions go?
EDIT: I just noticed wintermute's point, when looking at the Vifa (sensitivity of 96.5dB) and comparing it to the SEAS (89.5 dB) is it going to be a huge problem? I'm still looking for a tweeter to pair with it, I guess.
The SEAS tweeter that gifandy recommended has a 91 dB sensitivity, is that a better match or should I keep looking for something closer to 89?
Thanks for the suggestion. I think I will use the Vifa. I guess it's now time to get to designing the enclosure and crossover. I know it says 20.9 liters for the volume, but is there a preferred way to distribute the cabinet as far as dimensions go?
EDIT: I just noticed wintermute's point, when looking at the Vifa (sensitivity of 96.5dB) and comparing it to the SEAS (89.5 dB) is it going to be a huge problem? I'm still looking for a tweeter to pair with it, I guess.
The SEAS tweeter that gifandy recommended has a 91 dB sensitivity, is that a better match or should I keep looking for something closer to 89?
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Hardly true, I've gone through the sites. I'm looking and trying to apply the knowledge while making my own decisions. Relax, I appreciate your advice, I do -- I see the sites and I've gone through them, Zaph specifically because he does explain a lot like you said.
All that said, I'd prefer not to follow a template and try to find my own combination. I have time, so I'm not in a hurry to find the match, but I am trying to learn and come up with the design by myself.
There's something special I recognize in originality, and I'd make my own drivers if I thought I could (I can't.)
Thanks for the advice you've given, again, it's appreciated. I value the learning process more than a great speaker to be honest. Though, I'm sure as with anything, out of one comes the other.
Hi,
You can easly pad down the tweeter with a couple of resistors. The high sensitivity is good news as it means the tweeter is less likely to reach its excursion limit.
The bad news is to do this really well, you will need to measure both the drive units in the cabinets for both frequency response and impedance. Then import these responses into a simulation package and simulate a crossover. Since you have a microphone and all the software is available free this is not impossible it will mean learing how to use alot of quite difficult software tools though. The other alternative is to just use the microphone an suck it and see. For the Vifa I would try a 4.7R in series with an 10R in parallel with the tweeter to start with, however this is just a slightly educated guess and is very unlikly to be right you will need to itterate to get to a good result.
The 2dB diference to the seas tweeter will make this easier and you could just live with the slightly elevated HF response, or a small resistor in series will allow you to drop it a little (1 or 2R Ohms typically) this will change the response as well due to the interaction with the inductance of the tweeter. It depends on how deep you want to go.
Either way get the microphone working with a measurement package, I like Holm Acoustics package as it allow you to remove most of the room affects for higher frequencies by gating the response. At lower frequencies you can still make measurements but you need to do them near field. Once you have a microphone set up working you can try different resistors and even if you decide not to simulate you will at least be able to see what is happening.
I would also try playing with the BSC program at FRD (I gave you the link earlier) this way you can see how the placement of the drive units in the cabinet will affect the frequency response and optomise it. Once you have the front dimensions that work best you can work out the rest of the box.
Regards,
Andrew
You can easly pad down the tweeter with a couple of resistors. The high sensitivity is good news as it means the tweeter is less likely to reach its excursion limit.
The bad news is to do this really well, you will need to measure both the drive units in the cabinets for both frequency response and impedance. Then import these responses into a simulation package and simulate a crossover. Since you have a microphone and all the software is available free this is not impossible it will mean learing how to use alot of quite difficult software tools though. The other alternative is to just use the microphone an suck it and see. For the Vifa I would try a 4.7R in series with an 10R in parallel with the tweeter to start with, however this is just a slightly educated guess and is very unlikly to be right you will need to itterate to get to a good result.
The 2dB diference to the seas tweeter will make this easier and you could just live with the slightly elevated HF response, or a small resistor in series will allow you to drop it a little (1 or 2R Ohms typically) this will change the response as well due to the interaction with the inductance of the tweeter. It depends on how deep you want to go.
Either way get the microphone working with a measurement package, I like Holm Acoustics package as it allow you to remove most of the room affects for higher frequencies by gating the response. At lower frequencies you can still make measurements but you need to do them near field. Once you have a microphone set up working you can try different resistors and even if you decide not to simulate you will at least be able to see what is happening.
I would also try playing with the BSC program at FRD (I gave you the link earlier) this way you can see how the placement of the drive units in the cabinet will affect the frequency response and optomise it. Once you have the front dimensions that work best you can work out the rest of the box.
Regards,
Andrew
Hi,
This driver might integrate well with the Seas as it has a good extended response being a 28mm tweeter and if you really want the matched SPL its a 90dB part. However it has a slow acoustic roll off that woudl need to made part of the crossover.
Personally I would go with the Vifa even though it will need a bit more matching. Its low cost. Vifa usually create tweeters that punch above thier cost and whilst I haven't used this one I have had good results with earlier parts by them. (also Zaphs results for this part look very promising)
Regards,
Andrew
This driver might integrate well with the Seas as it has a good extended response being a 28mm tweeter and if you really want the matched SPL its a 90dB part. However it has a slow acoustic roll off that woudl need to made part of the crossover.
Personally I would go with the Vifa even though it will need a bit more matching. Its low cost. Vifa usually create tweeters that punch above thier cost and whilst I haven't used this one I have had good results with earlier parts by them. (also Zaphs results for this part look very promising)
Regards,
Andrew
I think I will go with the Vifa, I didn't realize I could bring down the sensitivity that easily. I figure with enough trial and error, I'll get it right. The Vifa looks impressive in general, I'm surprised at its price.
Do you have any advice in regards to how to distribute the dimensions of the enclosure? Like I said, I know it said 21 L, essentially, so would 11 x 12 x 14.5 in make sense?
Do you have any advice in regards to how to distribute the dimensions of the enclosure? Like I said, I know it said 21 L, essentially, so would 11 x 12 x 14.5 in make sense?
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