Omni,
Many thanks for your detailed reply. I'll need to read it again more thoroughly and reply as soon as I can! Thanks for spending so much time to explain it to me. grant
Many thanks for your detailed reply. I'll need to read it again more thoroughly and reply as soon as I can! Thanks for spending so much time to explain it to me. grant
grantnsw said:
Hi,
the way I see it it causes a drop in SPL of the quoted drivers sensitivity.
e.g. in a 2-way a 90dB bass/mid = an 85dB to 86dB speaker.
The Seas box includes BS and so does TG's graph, though
for the latter case the transition frequency is much lower.
🙂/sreten.
Omni,
I got a few DIY-Audio database errors and couldn't post so I emailed my reply to you. grant
I got a few DIY-Audio database errors and couldn't post so I emailed my reply to you. grant
Hi Sreten, my 'BS' conundrum continues.....lol
Thanks for your efforts to 'steer me straight'...
(Unfortunately, I haven't re-read as much as I would have liked eg True Audio link and ESP etc, but I'd like to comment if you can bear with me?)
I note that there could be a difference between 'true' infinite baffles, ie a very large size of say 4 by 8 feet where presumably there is no BS (gain? due to no 4 Pi space reflections/diffraction) AND 'pseudo'
type infinite baffles like Troels PMS where BS is not eliminated but the baffle frequency is reduced to a low enough point where it compliments the xo point. F3 = 11600 / (baffle width in cm). So for a
300Hz xo the baffle width would be somewhere between 45? to 60 cm and curved like the PMS to reduce diffraction.
I recall reading somewhere once that BS can be viewed either as a gain or loss, depending on how you 'look at it'. I haven't seen any test data yet that uses true I.Baffles (is this the IEC definition?) so everything else is 'finite' including Troels PMS and therefore includes BS to some degree.
I just read, right now, your latest post! quote: "The Seas box includes BS and so does TG's graph, though for the latter case the transition frequency is much lower". Yay, it seems like I'm not talking total rubbish after all!
My problem still lies here, quote: "the way I see it it causes a drop in SPL of the quoted drivers sensitivity. e.g. in a 2-way a 90dB bass/mid = an 85dB to 86dB speaker"....
BUT!.... if the 'real world' test scenario is done in a finite box where BS exists, albeit dissimilar in baffle dimensions to my existing box, then why should BS be subtracted? An example: MCA15 tested in 20L box of unknown width, my box 70 L I think, 35cm. So both have BS to some extent, and both could be a real situation perhaps, well maybe not 20L, but you know what I'm getting at. If a XO sim requires real data, then the subtraction is my stumbling block - surely it must be included somehow? The FRC and your comments indicate subtraction, so this is another 'leap of faith' for me!
A point I previously raised about the FRC process was that BS might be subtracted from the manuf.'s data, the new box BS value calculated and added back in. This is logical to me. Anyway, thanks for reading this...grant
Thanks for your efforts to 'steer me straight'...
(Unfortunately, I haven't re-read as much as I would have liked eg True Audio link and ESP etc, but I'd like to comment if you can bear with me?)
I note that there could be a difference between 'true' infinite baffles, ie a very large size of say 4 by 8 feet where presumably there is no BS (gain? due to no 4 Pi space reflections/diffraction) AND 'pseudo'
type infinite baffles like Troels PMS where BS is not eliminated but the baffle frequency is reduced to a low enough point where it compliments the xo point. F3 = 11600 / (baffle width in cm). So for a
300Hz xo the baffle width would be somewhere between 45? to 60 cm and curved like the PMS to reduce diffraction.
I recall reading somewhere once that BS can be viewed either as a gain or loss, depending on how you 'look at it'. I haven't seen any test data yet that uses true I.Baffles (is this the IEC definition?) so everything else is 'finite' including Troels PMS and therefore includes BS to some degree.
I just read, right now, your latest post! quote: "The Seas box includes BS and so does TG's graph, though for the latter case the transition frequency is much lower". Yay, it seems like I'm not talking total rubbish after all!
My problem still lies here, quote: "the way I see it it causes a drop in SPL of the quoted drivers sensitivity. e.g. in a 2-way a 90dB bass/mid = an 85dB to 86dB speaker"....
BUT!.... if the 'real world' test scenario is done in a finite box where BS exists, albeit dissimilar in baffle dimensions to my existing box, then why should BS be subtracted? An example: MCA15 tested in 20L box of unknown width, my box 70 L I think, 35cm. So both have BS to some extent, and both could be a real situation perhaps, well maybe not 20L, but you know what I'm getting at. If a XO sim requires real data, then the subtraction is my stumbling block - surely it must be included somehow? The FRC and your comments indicate subtraction, so this is another 'leap of faith' for me!
A point I previously raised about the FRC process was that BS might be subtracted from the manuf.'s data, the new box BS value calculated and added back in. This is logical to me. Anyway, thanks for reading this...grant
Hi,
The modelled baffle step can be added to infinite baffle data to
derive the box response (so at say ~ 100Hz BS is ~ -6dB = a loss)
or subtracted from the box response (now at ~ 100Hz - -6dB = +6dB)
to get the infinite baffle response.
So using Troels data for his baffle and BS responses for his baffle
and your box you subtract TGs baffle and add your box response.
The thing with the Seas data is it includes an unknown box, if your
really clever by comparing it to TG's data and messing around you
can derive the size of the unknown box, but why do that ?
🙂/sreten.
The modelled baffle step can be added to infinite baffle data to
derive the box response (so at say ~ 100Hz BS is ~ -6dB = a loss)
or subtracted from the box response (now at ~ 100Hz - -6dB = +6dB)
to get the infinite baffle response.
So using Troels data for his baffle and BS responses for his baffle
and your box you subtract TGs baffle and add your box response.
The thing with the Seas data is it includes an unknown box, if your
really clever by comparing it to TG's data and messing around you
can derive the size of the unknown box, but why do that ?
🙂/sreten.
Sreten, Hi,
Cautiously, I may be finally 'there'! (I hope), that is, I think you may have answered my question.
Quote: "So using Troels data for his baffle and BS responses for his baffle and your box you subtract TGs baffle and add your box response".
So, I very much hope that I have understood you correctly and presume the following approach is valid:
SPLTrace all 3 responses, ( ie, *1* = Troels PMS (pseudo) Infinite Baffle MCA response, *2* = Troels MCA BStep
response in PMS box, and *3* = the MCA simmed in my box in 'the Edge'.)
Then, numerically SUBTRACT *2* from *1* (by dB's per frequency) giving *4* and then ADD *3* to *4*.
I hope this process is what you intended. I'm being overly specific here because I need to get this right conceptually and also I don't want to cause any unnecessary confusion.
If this is correct, then, I'm now on my way! The only problem is that Troels has not specified the MCA BStep PMS box graph. I guess I could approximate a curved baffle of PMS dimensions in Svante's (flat baffled) 'Edge'?
Btw, I think I understand this now Q: " or subtracted from the box response (now at ~ 100Hz - -6dB = +6dB) to get the infinite baffle response." It took a while for me !, but hey, Thanks! grant
Cautiously, I may be finally 'there'! (I hope), that is, I think you may have answered my question.
Quote: "So using Troels data for his baffle and BS responses for his baffle and your box you subtract TGs baffle and add your box response".
So, I very much hope that I have understood you correctly and presume the following approach is valid:
SPLTrace all 3 responses, ( ie, *1* = Troels PMS (pseudo) Infinite Baffle MCA response, *2* = Troels MCA BStep
response in PMS box, and *3* = the MCA simmed in my box in 'the Edge'.)
Then, numerically SUBTRACT *2* from *1* (by dB's per frequency) giving *4* and then ADD *3* to *4*.
I hope this process is what you intended. I'm being overly specific here because I need to get this right conceptually and also I don't want to cause any unnecessary confusion.
If this is correct, then, I'm now on my way! The only problem is that Troels has not specified the MCA BStep PMS box graph. I guess I could approximate a curved baffle of PMS dimensions in Svante's (flat baffled) 'Edge'?
Btw, I think I understand this now Q: " or subtracted from the box response (now at ~ 100Hz - -6dB = +6dB) to get the infinite baffle response." It took a while for me !, but hey, Thanks! grant
Hi Omni,
Are you about? Where are you 'at' now , please, building-wise? I hope its all going well for you. I've hit some more 'snags' along the way. It seems that I have to buy Office 2000 to get XL to proceed.
And then, like you did, go through all the steep learning-curve process!
I tried several more times to model your FRC CA15 frd's in SW, but had insufficient data, and I could not get the 'calculate' ( +, -, and times/divide) options to work. No joy as yet on the SW new forum either. So, regarding baffle-step, ie, how to compensate for the MCA15 in my box, like you said, I'm baffled!
Anyway, I still truly want to pursue this. I'm an obstinate old f_rt! lol I believe it can be done...but how?, without proper measurements, is the question? The FRConsortium tools are my best alternative, imho.
I'm now seriously considering Troels 3WayClassic, the baffle dimensions are similar except for 200?mm difference in height. I modelled both the MCA12 and 15 in both boxes in Svante's 'the Edge' (similar driver placement on both baffles) and there was not much difference that I could see. The P25 Vifa woofer I think will
be fine, because as Sreten said the test-box and my box are very similar. Also, he said?, (because the MCA12 and 15 responses are so similar....I hope I'm correct) the MCA15 might give a reasonably 'approximate' result. Which is what I'm looking for 'after all'.
Btw, just for fun, Tony Gee's Modulus design looks very interesting still. Sreten, I think said it was esoteric? But nevertheless, excluding the 'smallish'? open MT baffle, and series XO, maybe looks modifiable for my proposed drivers? Just a thought. I know all of this is irrelevant to you Omni!, sorry I'm just *thinking* aloud.
best wishes to you (and everyone else!), grant
Are you about? Where are you 'at' now , please, building-wise? I hope its all going well for you. I've hit some more 'snags' along the way. It seems that I have to buy Office 2000 to get XL to proceed.
And then, like you did, go through all the steep learning-curve process!
I tried several more times to model your FRC CA15 frd's in SW, but had insufficient data, and I could not get the 'calculate' ( +, -, and times/divide) options to work. No joy as yet on the SW new forum either. So, regarding baffle-step, ie, how to compensate for the MCA15 in my box, like you said, I'm baffled!
Anyway, I still truly want to pursue this. I'm an obstinate old f_rt! lol I believe it can be done...but how?, without proper measurements, is the question? The FRConsortium tools are my best alternative, imho.
I'm now seriously considering Troels 3WayClassic, the baffle dimensions are similar except for 200?mm difference in height. I modelled both the MCA12 and 15 in both boxes in Svante's 'the Edge' (similar driver placement on both baffles) and there was not much difference that I could see. The P25 Vifa woofer I think will
be fine, because as Sreten said the test-box and my box are very similar. Also, he said?, (because the MCA12 and 15 responses are so similar....I hope I'm correct) the MCA15 might give a reasonably 'approximate' result. Which is what I'm looking for 'after all'.
Btw, just for fun, Tony Gee's Modulus design looks very interesting still. Sreten, I think said it was esoteric? But nevertheless, excluding the 'smallish'? open MT baffle, and series XO, maybe looks modifiable for my proposed drivers? Just a thought. I know all of this is irrelevant to you Omni!, sorry I'm just *thinking* aloud.
best wishes to you (and everyone else!), grant
Grant, Glad to read the good news about your continued committment on your project................I agree with you that the FRC tools may be your best option. Without all the measurement equipment and speaker design software that professionals use and costs loads of money to get up and running, I think FRC tools make speaker and crossover design accessible to us.........I will be hopefully validating this in the next 2 weeks............Crossover parts will be ordered on Monday, and during the interim, I will be putting finishing touches on the cabinet.................Baffle is finally finished with one exception : I need to sand around the driver mounting holes to make room for the drivers to freely fit........The multitude of paint and finishing coats have built up a little bit, which make fitting the drivers a bit of a tight squeeze.............Not a big deal, though...............The heavy lifting has been done..........This is just a minor detail..........As far as crossover parts is concerned, I ordered a few more resistors and capacitors than I will ultimately need.............I did this so that I will have the ability to tweak by ear with the components. I make this following offer to you : Once I get the design tweaked to my taste, I will be honored and pleased to send to you, for your use, the leftover parts, which will include Mills Resistors and a variety of Clarity Caps.................These are reported to be Great performing components { and if you have read Tony Gees Capacitor test } an excellent value................The components may not be all the values your crossover will need, however, they may provide you with some Great capacitor bypassing options, Same thing with the resistors.............I will have enough left over to provide you the ability to tweak..................Keep us posted............Omni
grantnsw said:
Hi,
The Modulus takes a series of design decisions it seems to me either
because the customer wanted it that way or something different.
IMO the "design" would not work well with a dome tweeter, the point
of the design being matching power and off axis responses through
a broad crossover region which is almost a two way, and this is hard
to understand exactly whats going on, never mind model.
The input impedance correction circuit is fairly pointless IMO.
🙂/sreten.
Omni,
Thanks, I'm so pleased that 'Frankie' is on track. You appear to be 'on the home stretch' now and almost finished the baffles. I think that Troels and Zaph indicated that it is important to chamfer the
back of the mid's cutout? I mention this just for interests sake, FWIW, and not suggesting you make any major changes at this late stage of your design.
Interestingly, 'SW' does apparently offer very comprehensive measurement facilities with a full-duplex sound card and electret/
condenser mike and preamp. (the Panasonic inserts are evidently very cheap like $1US! and a calibration file exists, but a 'Wallin-jig' is required and the process looks very complicated to me!)....again just for interest, if we both get seriously stuck! But I very much doubt this will be required as you so competently managed the FRC procedure.
Omni, ...my jaw just dropped... when I read your incredibly generous offer. Your kindness is amazing! Thank you so very much for your very sincere offer, but I do have to very politely decline, unfortunately. You may need those parts for another future project. Have you ever given away something only to realise later on, damn, I could sure use that now? You might get another tweaking idea later on which requires those parts, or a new xo mod. It is another extremely kind gesture on your part, but I really think you should hang on to them, just in case. If..., however, you are totally sure that you want to offload them, then I would *insist* on paying your full US$ cost price plus postage to Au. I'm sure this is ok with you?
(yes, thanks, I did read Tony G's cap test a while ago, but the results I've long forgotten)
Re: my project...well it's still in a hiatus! The 27TFFC and MCA15 still are my best options, imho. I've been re-reading Troels 3WayClassic and PMS (and Tony Gee's Modulus - but it seems too difficult / inappropriate? to modify) and now I'm leaning back to a modified PMS design. If I ever do get XL , I'd like to model my box with 'curved wing baffles' (similar to the PMS) in Unibox and go from there. I hope to create something that is not only , just good, but for value for money *to me* is truly awe-inspiring!...I believe the PMS is just that, but of course, I've never heard them! lol
Omni, we're all excited to find out what 'Frankie' version 1 sounds like on various recordings. Without trying to put a dampener on things, um, are you still confident the impedance is satisfactorily high enough to protect your amp? I'm just being (overly) cautious here as usual? most sincere regards, grant
Thanks, I'm so pleased that 'Frankie' is on track. You appear to be 'on the home stretch' now and almost finished the baffles. I think that Troels and Zaph indicated that it is important to chamfer the
back of the mid's cutout? I mention this just for interests sake, FWIW, and not suggesting you make any major changes at this late stage of your design.
Interestingly, 'SW' does apparently offer very comprehensive measurement facilities with a full-duplex sound card and electret/
condenser mike and preamp. (the Panasonic inserts are evidently very cheap like $1US! and a calibration file exists, but a 'Wallin-jig' is required and the process looks very complicated to me!)....again just for interest, if we both get seriously stuck! But I very much doubt this will be required as you so competently managed the FRC procedure.
Omni, ...my jaw just dropped... when I read your incredibly generous offer. Your kindness is amazing! Thank you so very much for your very sincere offer, but I do have to very politely decline, unfortunately. You may need those parts for another future project. Have you ever given away something only to realise later on, damn, I could sure use that now? You might get another tweaking idea later on which requires those parts, or a new xo mod. It is another extremely kind gesture on your part, but I really think you should hang on to them, just in case. If..., however, you are totally sure that you want to offload them, then I would *insist* on paying your full US$ cost price plus postage to Au. I'm sure this is ok with you?
(yes, thanks, I did read Tony G's cap test a while ago, but the results I've long forgotten)
Re: my project...well it's still in a hiatus! The 27TFFC and MCA15 still are my best options, imho. I've been re-reading Troels 3WayClassic and PMS (and Tony Gee's Modulus - but it seems too difficult / inappropriate? to modify) and now I'm leaning back to a modified PMS design. If I ever do get XL , I'd like to model my box with 'curved wing baffles' (similar to the PMS) in Unibox and go from there. I hope to create something that is not only , just good, but for value for money *to me* is truly awe-inspiring!...I believe the PMS is just that, but of course, I've never heard them! lol
Omni, we're all excited to find out what 'Frankie' version 1 sounds like on various recordings. Without trying to put a dampener on things, um, are you still confident the impedance is satisfactorily high enough to protect your amp? I'm just being (overly) cautious here as usual? most sincere regards, grant
Grant, Thank you for your input, here, and your kind words of compliment. We will only know if I managed the FRC tools competently, when I turn on the amp.............Hopes are high, and I appreciate your confidence....... I will keep you posted on the extra capacitors and resistors and can later let you know what values are left over in case they may be of use to you.........I just sent my orders in this evening via Fed Ex..............We got a major snow storm headed our way, and I am pleased that I got my orders sent prior to the storm entering our territory.........Blizzard is the prediction so I hope shipping isn't delayed here in the next several days.........................I did read Zaphs description on chamfering the inside of the baffles, some time ago......Good News......I chamfered both the Midbass and the Woofer...........Impedance question..........I hope so............It runs along the same lines as Bagbys 3 way example...........Minimum impedance is at 5.24 ohms, so once I am up and runnin' I will start at low volume and periodically feel the amplifier for heat, then if all is well, will slowly crank it up.............I listen to a very eclectic collection of music, spanning from Rock and Roll of the likes of Pink Floyd, Zeppelin and a wide variety in the 60's and 70's. I'll even fit in a bit of KISS.........I also listen to some Jazz, and an outfit called SPYRO GYRA, which sports a plethora of dazzling sounds, I can't wait to sink my teeth into. But also, I definately dig BACH.............Kick *** violin concertos.........I will absolutely be able to give you all my report on a multitude of pieces..........Got any suggestions on artists? .............I have observed that you have set high hopes for your project, and shifting gears in the drivers was your first step, in the right direction, after all the hassles we went through in tryin' to model that CA15RLY............Cool............. What is the PMS?..Is it on Troels site?...........I am definately gonna have to read about it. You sound very thrilled about it..............sounds to me like a gut instinct has hit you....Go with it.........You have the gift, man............. and I am very certain you will achieve that AWE-INSPIRATION.........I look forward to being in touch throughout your progress................Following the likes of Zaph and Troels, and all the study you have put into this, you can't go wrong..............Warm Regards......Omni
Hi, to you all....Omni,... lets hope it will make the violins sing
Have you listened to Beethovens String Quartets...I am fortunate to have the complete set.....and Vivaldi is nice too🙂
Have you listened to Beethovens String Quartets...I am fortunate to have the complete set.....and Vivaldi is nice too🙂
Hi Sreten,
Thanks for your further Modulus info, yes, I'll discard the idea of trying to modify it with the Seas drivers. So, I'll continue with the 27TFFC and MCA15's in my box, and still try to find ways to model things
adequately without most of the FRC tools or measurements. Re: my previous overly simplified post about adding and subtracting BS; I have not as yet been able to get the SW Calculate function to work. thanks, grant
Thanks for your further Modulus info, yes, I'll discard the idea of trying to modify it with the Seas drivers. So, I'll continue with the 27TFFC and MCA15's in my box, and still try to find ways to model things
adequately without most of the FRC tools or measurements. Re: my previous overly simplified post about adding and subtracting BS; I have not as yet been able to get the SW Calculate function to work. thanks, grant
Hi Omni,
Wow, you've got some wild weather over there! I guess you're well prepared for it though. Good to hear that the 'chamfering' is already 'sorted'. I was very entertained to learn of your eclectic music tastes as mine are similar....we're both probably 'baby-boomer' vintage! Except I've never heard of Spyro Gyra - I'll google them just for fun. I really like 'jazz alto-sax' especially e.g. Steely Dan's 'FM', and lots of other stuff, ...Robert Plant's 'Big Log' comes to mind. I like JS Bach too, when you can crank 'Frankie' up loud and want to test the Peerless try Toccata and Fugue in D Minor, but I hope your home's
foundations are solid! hehe. Ever heard Heart('s) 'Barracuda'? - heavy RnR, but I like it! I used to put the portable CD in a plastic bag and go windsurfing/wavejumping to it...what a blast! (the CD player soon .died.)
*Back on topic* ---> the CA15 response slight 'dip' appears to be consistent with other Seas drivers, namely the MCA12 and to a slightly lesser extent the MCA15 as well (but this could be magnified by box/baffle dimensions?) Please see the attached Troels Gravesen charts. The 'Poor Mans Strad' ...PMS...(MCA15) is on top and his 3WayClassic response (with the MCA12 mid) is below.
Troels site IS, imo, mandatory reading - its not just good , its amazing! The sheer number and quality of designs and their very detailed description and anaylsis is truly a gift to us DIY-ers. www.troelsgravesen.dk
Other sites are brilliant too of course, and equally amazing and helpful, I'm sure you know them all!
Wow, thanks for your kind words and belief in my abilities, but Omni, I have frequent problems understanding the most basic concepts. I'm a real 'plodder', but I'm still optimistic! I reckon the Seas 27TFFC & MCA15 with my old Vifa P25 in my (possibly modified boxes..aprroximating the PMS) could be a real 'goer'.
I have just installed 2 *free licence* Office Suites including Spreadsheets i.e. 'Open Office' (dot Org) and 'Ashampoo'
(funny name!) Office 2005. So far both open FRC Unibox, but both don't seem to have the required 'macros'...<grrr>
I'll have another try tomorrow, but maybe the cell calculations are not the same anyway?... best wishes! , grant
*Tinitus*....Hi! I'm happy to see you're here! How are you and what's happening?
Wow, you've got some wild weather over there! I guess you're well prepared for it though. Good to hear that the 'chamfering' is already 'sorted'. I was very entertained to learn of your eclectic music tastes as mine are similar....we're both probably 'baby-boomer' vintage! Except I've never heard of Spyro Gyra - I'll google them just for fun. I really like 'jazz alto-sax' especially e.g. Steely Dan's 'FM', and lots of other stuff, ...Robert Plant's 'Big Log' comes to mind. I like JS Bach too, when you can crank 'Frankie' up loud and want to test the Peerless try Toccata and Fugue in D Minor, but I hope your home's
foundations are solid! hehe. Ever heard Heart('s) 'Barracuda'? - heavy RnR, but I like it! I used to put the portable CD in a plastic bag and go windsurfing/wavejumping to it...what a blast! (the CD player soon .died.)
*Back on topic* ---> the CA15 response slight 'dip' appears to be consistent with other Seas drivers, namely the MCA12 and to a slightly lesser extent the MCA15 as well (but this could be magnified by box/baffle dimensions?) Please see the attached Troels Gravesen charts. The 'Poor Mans Strad' ...PMS...(MCA15) is on top and his 3WayClassic response (with the MCA12 mid) is below.
Troels site IS, imo, mandatory reading - its not just good , its amazing! The sheer number and quality of designs and their very detailed description and anaylsis is truly a gift to us DIY-ers. www.troelsgravesen.dk
Other sites are brilliant too of course, and equally amazing and helpful, I'm sure you know them all!
Wow, thanks for your kind words and belief in my abilities, but Omni, I have frequent problems understanding the most basic concepts. I'm a real 'plodder', but I'm still optimistic! I reckon the Seas 27TFFC & MCA15 with my old Vifa P25 in my (possibly modified boxes..aprroximating the PMS) could be a real 'goer'.
I have just installed 2 *free licence* Office Suites including Spreadsheets i.e. 'Open Office' (dot Org) and 'Ashampoo'
(funny name!) Office 2005. So far both open FRC Unibox, but both don't seem to have the required 'macros'...<grrr>
I'll have another try tomorrow, but maybe the cell calculations are not the same anyway?... best wishes! , grant
*Tinitus*....Hi! I'm happy to see you're here! How are you and what's happening?
Attachments
Hi, all is well, too much actually .... everything sounding just fine, so I am only listening to music ... last remedy....notch filter...ouch😀
But I am in the process of a bit of treachery.... piching up an old hobby ..... DIY RIBBONS ...... you would like that 😎
But now you have advanced, why not try something different and use your skills ..... could be the new Peerless HDS tweeter .... you could the first to use it ....and a midrange with a little more efficiency ..... still wonder which one.....and a bass with even more power ....nahhhh, just teasing
But I am in the process of a bit of treachery.... piching up an old hobby ..... DIY RIBBONS ...... you would like that 😎
But now you have advanced, why not try something different and use your skills ..... could be the new Peerless HDS tweeter .... you could the first to use it ....and a midrange with a little more efficiency ..... still wonder which one.....and a bass with even more power ....nahhhh, just teasing
Hi Tinitus,
I've been intrigued since you mentioned your notion of resistors in series with parallel components in parallel xo networks and the benefits to be gained.. At one stage I did model an 'Omni XO variant' for his scenario and found a 'positive', that is, *good variance* with series resistors on parallel components (dB wise, albeit small, but still possibly discernible), so I was surprised and I must also say, delighted to find the resistor in Troels 'PMS' version 5 XO. Am I correct here, please?
Please see Troels G. circuit attached. Does this indicate what you are suggesting? And , if so, would the resistor's value need to be subtracted from the coil's DCR? Also, I thought attenuation resistors should be placed next to, but preceding Zobels?...from the Amp? If you know what I mean...i.e. just before the Zobel across the driver. Would an L-Pad be better here to maintain a more constant impedance, do you think?
Also, Vivaldi... the Four Seasons - is great! thanks, Tinitus.....best wishes, grant
I've been intrigued since you mentioned your notion of resistors in series with parallel components in parallel xo networks and the benefits to be gained.. At one stage I did model an 'Omni XO variant' for his scenario and found a 'positive', that is, *good variance* with series resistors on parallel components (dB wise, albeit small, but still possibly discernible), so I was surprised and I must also say, delighted to find the resistor in Troels 'PMS' version 5 XO. Am I correct here, please?
Please see Troels G. circuit attached. Does this indicate what you are suggesting? And , if so, would the resistor's value need to be subtracted from the coil's DCR? Also, I thought attenuation resistors should be placed next to, but preceding Zobels?...from the Amp? If you know what I mean...i.e. just before the Zobel across the driver. Would an L-Pad be better here to maintain a more constant impedance, do you think?
Also, Vivaldi... the Four Seasons - is great! thanks, Tinitus.....best wishes, grant
Attachments
grantnsw said:
Hi, the very short answer is no, and yes you could use a 2.2R air core, 🙂/sreten.
No, I must admit, its not the same thing
First...att. resistor....I have never understood why people place the tweeter series resistor before filter....it is presented to a whole lot more power
I can see its convenient, because it dont affect filter function in the same way if you change its value
But fact is that to have the desired attenuation a series resistor needs to be much bigger than that of a L-pad .... and smaller does have a tendency to sound better
And with L-pads you can make VERY small adjustments to the filter function, by adjusting the L-pad
As to the series resistor on paralel components
The one troels place on the coil is insignificant and merely to adjust dc-resistance
Now, the one he places on the paralel C is a bit bigger and may have some effect to filter function, but I guess it mostly affects Q-values in this way
At the moment I have 12ohm on midrange paralel C
It surely does a number of things but mostly corrects impedance load ..... what ever adjustments I do, doesnt change the sound much ..... but it clearly has an important influence on phase ..... I think the key word is ambience and precision in soundstage
Ah, I forgot.....at the moment I am playing with "notch" filters
Too bad I cant document anything
First...att. resistor....I have never understood why people place the tweeter series resistor before filter....it is presented to a whole lot more power
I can see its convenient, because it dont affect filter function in the same way if you change its value
But fact is that to have the desired attenuation a series resistor needs to be much bigger than that of a L-pad .... and smaller does have a tendency to sound better
And with L-pads you can make VERY small adjustments to the filter function, by adjusting the L-pad
As to the series resistor on paralel components
The one troels place on the coil is insignificant and merely to adjust dc-resistance
Now, the one he places on the paralel C is a bit bigger and may have some effect to filter function, but I guess it mostly affects Q-values in this way
At the moment I have 12ohm on midrange paralel C
It surely does a number of things but mostly corrects impedance load ..... what ever adjustments I do, doesnt change the sound much ..... but it clearly has an important influence on phase ..... I think the key word is ambience and precision in soundstage
Ah, I forgot.....at the moment I am playing with "notch" filters
Too bad I cant document anything
tinitus said:
Hi,
Ahh..... but it does.
It affects the source impedance driving the network which is no
longer effectively a short (amplifier output impedance) but the
value of the series resistor you use.
So it changes the Q of the filter, and makes amplifier output
impedance pretty much irrelevant, transistor or valve.
It is true the resistor sees more power, the inductor current.
🙂/sreten.
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