Hi stuart,
what ever be teh case, I stricly advice against using B channel, or for taht matter any AMP directly hooked to a tweeter...
you can easily damage it..!!
best would be to put atleast a series cap and may be an attn.,
Amplifiers are nasty devices, and tweeers extremely sensitive...
most of these have nothing more than a deposited conductive film on the voice coil. So its relatively easy to see smooke..!!
Naveen, tcp, george....comments...!!!
ajju
what ever be teh case, I stricly advice against using B channel, or for taht matter any AMP directly hooked to a tweeter...
you can easily damage it..!!
best would be to put atleast a series cap and may be an attn.,
Amplifiers are nasty devices, and tweeers extremely sensitive...
most of these have nothing more than a deposited conductive film on the voice coil. So its relatively easy to see smooke..!!
Naveen, tcp, george....comments...!!!
ajju
I have just put the whole thing together and continue to use it. The finishing is not done yet. I wanted to build a speaker measurement jig to use with Speaker Workshop but I just got a plastic box and fitted the switches and RCA sockets. The parts are just lying around. Absolutely no time to do it. God alone knows when I will finish the project.
Which brand did you buy and how much did you pay? My LCR meter is Mastech and it cost me Rs. 1900 about two years ago.
Which brand did you buy and how much did you pay? My LCR meter is Mastech and it cost me Rs. 1900 about two years ago.
Hi, guys! 
I have finally decided that I can't (won't?) remain a kit builder all my diyaudio life. I'll have to design my own speakers, and I can't see how I can do that without learning to use speaker design and xo optimisation software. So this struggle. My aim is to finish the design and building of an MTM floorstander with Peerless India Kevlar midbass drivers and Peerless India fabric dome tweeters, in perhaps six to eight weeks. I've reached the point where I should be able to finish doing basic T/S params measurement of the Kevlars in the next couple of days, after which I'll design the enclosure and hand it over to Karpenter Sahib for fabrication. Once he starts on that, I'll start assembling a mic cable for doing SPL measurements with SW. I hope to actually complete the first-cut speaker by end of September.
That was just to tell you where I've been. I have a half-completed Gainclone-driven active MTMMM design which I'll pick up after the Kevlar MTMs are done.
Now that that's out of the way and I've caught my breath... yes! The FR driver and tweeter. I think it's basically a great idea. I personally believe that if you're not religious about FR, then an FR driver should not be used as a single-driver unit --- it should be used as a wide-range driver. It can act as midrange or midbass or mid-tweet, depending on its size and characteristics. "FR" drivers which can act as mid-tweets are rare --- the only ones I know are the Jordan JX53 (2") and its cousin in more ways than one, the Bandor 2" driver. Otherwise, most FRs are best used as midranges in 3-way designs (including my Jordan JX92S and most smaller TangBands and Fostex's), or as wide-range midbass units in two-way designs (e.g. the larger Fostex's, 8" and above, and the larger Jordans).
As some of you probably remember, I've been evangelising this approach (without actually building anything myself ) for more than a year. But if I had to build something, I'd need to learn how to design xo's, hence I'm now heading up the xo design path.
So, if you want to add a tweeter to that FR box, it may need some xo work. At the simplest, you can try doing active LR4 xo and bi-amping at a fairly high xo point, e.g. 4-6KHz. With a 4" FR driver, you often have the luxury of xo'ing that high, in which case you can use a stock active LR4 and not bother with xo design and optimisation.
Am back in DIY audio after a gap of almost a year, I think. Have suspended all my electronics activities, and have decided to bell the speaker-design cat. Am now working with Speaker Workshop, under the watchful virtual eyes of Gooroo Angshoo. Have built an impedance jig, and have measured some impedance curves of Indian drivers. (See my post elsewhere in this forum, search for "MLS".)ajju said:
I have finally decided that I can't (won't?) remain a kit builder all my diyaudio life. I'll have to design my own speakers, and I can't see how I can do that without learning to use speaker design and xo optimisation software. So this struggle. My aim is to finish the design and building of an MTM floorstander with Peerless India Kevlar midbass drivers and Peerless India fabric dome tweeters, in perhaps six to eight weeks. I've reached the point where I should be able to finish doing basic T/S params measurement of the Kevlars in the next couple of days, after which I'll design the enclosure and hand it over to Karpenter Sahib for fabrication. Once he starts on that, I'll start assembling a mic cable for doing SPL measurements with SW. I hope to actually complete the first-cut speaker by end of September.
That was just to tell you where I've been. I have a half-completed Gainclone-driven active MTMMM design which I'll pick up after the Kevlar MTMs are done.
Now that that's out of the way and I've caught my breath... yes!
The FR driver and tweeter. I think it's basically a great idea. I personally believe that if you're not religious about FR, then an FR driver should not be used as a single-driver unit --- it should be used as a wide-range driver. It can act as midrange or midbass or mid-tweet, depending on its size and characteristics. "FR" drivers which can act as mid-tweets are rare --- the only ones I know are the Jordan JX53 (2") and its cousin in more ways than one, the Bandor 2" driver. Otherwise, most FRs are best used as midranges in 3-way designs (including my Jordan JX92S and most smaller TangBands and Fostex's), or as wide-range midbass units in two-way designs (e.g. the larger Fostex's, 8" and above, and the larger Jordans).As some of you probably remember, I've been evangelising this approach (without actually building anything myself
) for more than a year. But if I had to build something, I'd need to learn how to design xo's, hence I'm now heading up the xo design path.So, if you want to add a tweeter to that FR box, it may need some xo work. At the simplest, you can try doing active LR4 xo and bi-amping at a fairly high xo point, e.g. 4-6KHz. With a 4" FR driver, you often have the luxury of xo'ing that high, in which case you can use a stock active LR4 and not bother with xo design and optimisation.
Lots of sage advice from all. Cheers.
Good to see more pictures also. I think I started something here.
As for the tweeter addition, I understand that hooking a tweeter directly to an amp is a disaster, but I remember from a long time ago when living in the States, Radio SHack had these auxiliary independant tweeter thingamabobs that would sit on top of the enclosure. This was what I was thinking of.
Indeed, any integrated addition would require a XO. TCPs idea is appreciated and perhaps I will use this solution in the future. I just feel that I would be giving up to soon on the single driver theory. I know I am a bit nuts on this, but from what I understand (and heard!) the XO can really color the sound in a negative way. You guys seem all very advanced in that you are capable of designing customized XOs, use Speaker Workshop without a flinch. I am still yet to spend time with SW, or any other programs that can assist in designin the best enclosures, etc.. (only used the Rutter spreadsheet to help with the dimentions of the TQWT). Certainly, reading your posts encourages me to dive in and figure this stuff out. I am basically approching this from the soft/artisitc direction and less from the technical/engineering angle...mainly because I am not an engineer. I have an apptitude to computer technologies but am mostly facinated by the incredible puzzle of making
great sounding, unique, audiophile quality speakers....that still always can improve!
I suppose the bast way to approach my dilema is to have different speakers for different music. The folded TQWTs are great for small jazz and classical groups, accoustic rock, etc. Anything that requires more sonics would need to be bigger and probably with another design. Although I heard that rear loaded horns are more versitile.
Nice conversations!!
Stuart
Good to see more pictures also. I think I started something here.
As for the tweeter addition, I understand that hooking a tweeter directly to an amp is a disaster, but I remember from a long time ago when living in the States, Radio SHack had these auxiliary independant tweeter thingamabobs that would sit on top of the enclosure. This was what I was thinking of.
Indeed, any integrated addition would require a XO. TCPs idea is appreciated and perhaps I will use this solution in the future. I just feel that I would be giving up to soon on the single driver theory. I know I am a bit nuts on this, but from what I understand (and heard!) the XO can really color the sound in a negative way. You guys seem all very advanced in that you are capable of designing customized XOs, use Speaker Workshop without a flinch. I am still yet to spend time with SW, or any other programs that can assist in designin the best enclosures, etc.. (only used the Rutter spreadsheet to help with the dimentions of the TQWT). Certainly, reading your posts encourages me to dive in and figure this stuff out. I am basically approching this from the soft/artisitc direction and less from the technical/engineering angle...mainly because I am not an engineer. I have an apptitude to computer technologies but am mostly facinated by the incredible puzzle of making
great sounding, unique, audiophile quality speakers....that still always can improve!
I suppose the bast way to approach my dilema is to have different speakers for different music. The folded TQWTs are great for small jazz and classical groups, accoustic rock, etc. Anything that requires more sonics would need to be bigger and probably with another design. Although I heard that rear loaded horns are more versitile.
Nice conversations!!
Stuart
s_zimble said:
Yes, many people have said this. And this becomes of particular issue when dealing with wide-range or "full-range" drivers, and adding a tweeter through a very shallow first-order xo. Such an xo often has just a single cap in the signal path. Since that cap is the only thing in the path, experimenters have often reported that the quality, brand, model, make, colour, magnetic orientation, temperature, price (yes!!! price!!!) and every other attribute of the cap makes subtle audible differences. In this case, it's sort of believable since it's the only item in the signal path. What makes it worse is that these full-range fanatics often opt for the very best in tweeters --- maybe some expensive planar or ribbon tweeters, which are very detailed and revealing. In such cases, the cap-to-cap differences are even more audible, strengthening their claim that "the best xo is no xo".
But laws of physics make conventional piston-movement electrodynamic drivers unsuitable across very wide frequency ranges. Small drivers (e.g. tweeters) can't have large enough Xmax to do good lows, and large drivers begin to beam and show cone breakup at high frequencies. So, laws of physics come in the way of the FR fanatic's love of his FR, but then let's not colour love with logic.
Don't misunderstand me --- I quite like the FR lovers as a community (my very first DIY speakers were a pair of single-driver FR boxes with expensive Jordan drivers) --- but I feel the FR approach loses much more by compromising on the driver limitations than they gain by omitting the xo. That's just a matter of personal opinion. I feel that an xo can always be made better (maybe even made active or PLLXO), but laws of physics like beaming or limitations of material science like cone breakup are much harder to fight. I'm an engineer, by temperament and qualification.
Actually, there are genuine reasons to dislike passive speaker-level xo. Most of these problems disappear if you switch to line-level xo, whether active or passive, whether valve or solid-state. The conventional PSLXO is the worst.
Absolutely.
There are many others who have gone this way. They use MOSFET amps and closed-box sealed woofers with active equalisation for Dire Straits and Wishbone Ash, and valve amps and FR drivers on open baffles to get into the "mood" with "Diamonds and Rust" and a glass of good 20-year-old port. I think this multi-system approach makes a lot of sense for those who can manage it.Even in my case, I can't imagine my being able to design, build or buy an all-rounder speaker which can beat my FR Jordans for certain --- and only certain --- kinds of music. For other kinds of music, many less sophisticated speakers will leave the Jordans in the dust, specially in the areas of hard driving bass and sharp, forward, dynamics. So, if I were to take the multi-system approach, the Jordans would be perfect for certain types of music.
Hi TCP,
All very valid points and understandable explainations. I could tell from your earlier posts that you were an engineer (or like animal). We are all lucky to have your great advice and insight. Cheers!
Just as an explaination, I entered this hobby with very basic knowledge, so I figured the FR / SD route was the fastest way to a finished product...and it seems to be that way. I wish that I was closer to your neighborhood so I can see some of these testing and design programs in action by some experienced people. Although it is also interesting to read the "Humble Homemade HiFi" sight (those who don't know it should make a visit) were Tony's excellent descriptions of his development process (for loudspeakers) shows his appreciation for "build and listen" and compares/contrasts with simulation and design programs, which are often off the mark. Makes me wonder if the dimentions of my enclosures are really wrong....
For sure, the more I listen to my TQWT single driver units, the more flaws I hear, especially with music with more than three instruments. Even there, Bill Evans is sounding much better than latter improv Coltrane.
I will have to think hard about the next project with my 103E's and these odd ball P700's (6cm FR Fostex!).
Stuart.
All very valid points and understandable explainations. I could tell from your earlier posts that you were an engineer (or like animal). We are all lucky to have your great advice and insight. Cheers!
Just as an explaination, I entered this hobby with very basic knowledge, so I figured the FR / SD route was the fastest way to a finished product...and it seems to be that way. I wish that I was closer to your neighborhood so I can see some of these testing and design programs in action by some experienced people. Although it is also interesting to read the "Humble Homemade HiFi" sight (those who don't know it should make a visit) were Tony's excellent descriptions of his development process (for loudspeakers) shows his appreciation for "build and listen" and compares/contrasts with simulation and design programs, which are often off the mark. Makes me wonder if the dimentions of my enclosures are really wrong....
For sure, the more I listen to my TQWT single driver units, the more flaws I hear, especially with music with more than three instruments. Even there, Bill Evans is sounding much better than latter improv Coltrane.
I will have to think hard about the next project with my 103E's and these odd ball P700's (6cm FR Fostex!).
Stuart.
1. you forget the Fostex FF85K among others
2. an option one can consider is what is proposed by Ted Jordan (JX125 with JX53) using 2 wide range drivers at opposite ends of teh freq. sepctrum. One can then escape using not inductor and just one capacitor. for example the above mentioned Fostex ff85K with a good paper cone midbass (SEAS, Vifa or Fostex).
Forgive me Navinbhai... I was not really making an exhaustive catalogue.navin said:
Yes, this is an exceptional combination, I'm told, but then this is a pair crafted by the same master craftsman and therefore works very well together. When was the last time you saw the natural acoustic rolloff at the top end of a midbass driver being so perfect that it can be matched to a tweeter with a 1st order xo on just the tweeter? This is a totally unique rarity, I feel.
Do not be swayed by what I post. I have more writing ability than knowledge.s_zimble said:
Ditto, the story of my Jordans.
Where are you located physically?
Yes! This gradual learning and ability to discriminate is so typical... it's happened to me with each project.
How do you obtain your Fostex drivers?
Hi TCP,
To answer your questions:
I am currently in New Delhi;
And I was fortunate enough to have had an opportunity to go to Tokyo for a short work related trip. While there, I ran around on a Sunday and found a shop that specializes in DIY speaker stuff. This is where I got the Fostex's. Unfortunately one of the little P700's coil is scrapping a little. You hear it breaking up a bit when playing sound through it. The other one sounds great, though. They were niffty kits that you build your self. Very instructive for me. I guess I was not careful enough on one of them. Does any one know a trick to fix this problem??
BTW, they were distributed by a DIY mag in Japan called Gallen (I think, because this was the name printed on the magnet). You might be able to find an email address and mail order them. I also saw a stack of these boxed kits in the store I bought my 103's at. I have an email/website for them too, but no one there speaks English (at least in person. Perhaps on email it will be easier to communicate).
Let me know if you're interested in this info.
Stuart
To answer your questions:
I am currently in New Delhi;
And I was fortunate enough to have had an opportunity to go to Tokyo for a short work related trip. While there, I ran around on a Sunday and found a shop that specializes in DIY speaker stuff. This is where I got the Fostex's. Unfortunately one of the little P700's coil is scrapping a little. You hear it breaking up a bit when playing sound through it. The other one sounds great, though. They were niffty kits that you build your self. Very instructive for me. I guess I was not careful enough on one of them. Does any one know a trick to fix this problem??
BTW, they were distributed by a DIY mag in Japan called Gallen (I think, because this was the name printed on the magnet). You might be able to find an email address and mail order them. I also saw a stack of these boxed kits in the store I bought my 103's at. I have an email/website for them too, but no one there speaks English (at least in person. Perhaps on email it will be easier to communicate).
Let me know if you're interested in this info.
Stuart
Ok.
Here it goes:
I made a typo. The magazine, or it is more like an online shop with all kinds of strange stuff, is called Gakken. The web link for "sophisticated Science Kits for Adults"
(http://shop.gakken.co.jp/otonanokagaku/index.html)
has a link with a picture of a DIY speaker. This link
(http://shop.gakken.co.jp/otonanokagaku/magazine/sp/index.html)
shows the little P700 and the magazine contents.
The shop I went to is called Koizumi
(http://koizumi-musen.com)
you can try to email them
(tsu-han@koizumi-musen.com)
I have not try this yet, but was thinking to email Koizumi to get another P700 kit since one of my tries did not work so well. If I recall the kits were somewhere between 2500 and 3000 yen, which is between 21 and 26 USD.
Stuart.
Here it goes:
I made a typo. The magazine, or it is more like an online shop with all kinds of strange stuff, is called Gakken. The web link for "sophisticated Science Kits for Adults"
(http://shop.gakken.co.jp/otonanokagaku/index.html)
has a link with a picture of a DIY speaker. This link
(http://shop.gakken.co.jp/otonanokagaku/magazine/sp/index.html)
shows the little P700 and the magazine contents.
The shop I went to is called Koizumi
(http://koizumi-musen.com)
you can try to email them
(tsu-han@koizumi-musen.com)
I have not try this yet, but was thinking to email Koizumi to get another P700 kit since one of my tries did not work so well. If I recall the kits were somewhere between 2500 and 3000 yen, which is between 21 and 26 USD.
Stuart.
Delhi is the place where my diyaudio guru, Gooroo Angshoo XOMaharaj, lives. You can see his postings here under the moniker "angshudas", and most of what I know of hands-on diyaudio has come from him. He's been building speakers and amps for 30+ years now. He stays in Gurgaon. If you want a friendly and knowledgeable diyer to chat with, you must contact him. He eats frequency curves for breakfast and draws doodles on TO3 packs when he's bored. He's currently teaching this totally unworthy disciple how to use Speaker Workshop. Send him email through diyaudio! I'm sure he'll be good to chat with --- he's one of the nicest people I've encountered through diyaudio, and I've encountered a few more equally nice people in Jamshedpur, B'lore and elsewhere.s_zimble said:
I don't know whether such problems are fixable.
Thanks for all the pointers, but I think it'll be easier for me to get something from the US than from Japan. I'll try the Madisound-via-friend route.
Hi TCP.
Thanks for the tip on the Guru....I will try to make contact. I would like to learn SW as well.
As for Japan vs USA: I guess it all matters if someone is traveling and can bring stuff in. I assume that shipping would entail large customs duties.
I am also being swayed a bit by your argument to add tweeters to my FR single driver cabinets. I found a pair of JBL surface mount tweeters (2.5khz-21khz) for 2500 INR (seems a bit pricy). They look pretty good. Not sure of the sound. The biggest question is the XO (my worst fear). You made some interesting suggestions, one being that I could find some sort of stock, pre-assembled XOs that are of reasonable quality. Can you, or anyone, suggest to me where to get this type of thing? I am not sure I am knowledgable enough to build my own...yet
CHeers!
Thanks for the tip on the Guru....I will try to make contact. I would like to learn SW as well.
As for Japan vs USA: I guess it all matters if someone is traveling and can bring stuff in. I assume that shipping would entail large customs duties.
I am also being swayed a bit by your argument to add tweeters to my FR single driver cabinets. I found a pair of JBL surface mount tweeters (2.5khz-21khz) for 2500 INR (seems a bit pricy). They look pretty good. Not sure of the sound. The biggest question is the XO (my worst fear). You made some interesting suggestions, one being that I could find some sort of stock, pre-assembled XOs that are of reasonable quality. Can you, or anyone, suggest to me where to get this type of thing? I am not sure I am knowledgable enough to build my own...yet
CHeers!
There is a speaker maker in Delhi called BOLTON . They make crossovers too. I've seen some of them.
Go to the electronics market and ask for Bolton crossovers. There is a range of them though I have no idea what all they have. If I remember right , inductors were on a iron powder or ferrite core and caps were electrolytic types.
They were not specifically made to suit any of their drivers - just general purpose types for 4 ohms and and another for 8 ohms. You could always alter the inductance values and change capacitors to suit your need.
Cheers.
Go to the electronics market and ask for Bolton crossovers. There is a range of them though I have no idea what all they have. If I remember right , inductors were on a iron powder or ferrite core and caps were electrolytic types.
They were not specifically made to suit any of their drivers - just general purpose types for 4 ohms and and another for 8 ohms. You could always alter the inductance values and change capacitors to suit your need.
Cheers.
Actually, I was referring to a stock active XO. There are many companies abroad which provide kits for this, including Marchand Electronics, Rod Elliott and others. But if you get such an XO, it'll work at line level, and you will get two line-level outputs from the XO. You will then have to feed this to two separate channels of power amps, and connect the output of each power amp to one driver. Thus, for your FR driver and tweeter, you'll need one LR4 active XO, two small power amps (you could make something using LM3875 or LM3886), and connect one to the FR driver, the other to the tweeter. For a stereo setup, you'd need two active XOs and four power amps.s_zimble said:
Stock passive XO are unusable off the shelf... they are merely toys. They assume that each driver has precisely 8 Ohm or 4 Ohm load, and moreover, that this is resistive, i.e. the impedance will remain flat across the freq range. This is fantasy... no real driver behaves this way. This impedance unevenness will result in horrible sounding speakers. Therefore, there's no such thing as a listenable off-the-shelf passive XO. The market which buys these off-the-shelf passive XO are basically the band-baajaa parties who make big boxes with 12" woofers, small tweeters, and then stick an off-the-shelf passive XO into it to ensure that some semblance of sound comes out of both woofer and tweeter without blowing up either driver. You don't want to be associated with that quality of sound, I'm sure.
4 amps!!!! My wife will kill me.
This is one of the reasons I may stick to the challenge od single drivers.
I am considering making a similar folded TQWT or TL for the JBL60 (the 6" version of the 40's). I can get a pair for RS. 1250 and the quoted range is 90hz-19khz. It would be interesting to put them through a Speaker WKSP test to see what they really are.
I also saw a blaupunkt set of surface mount tweets and a matched pair of XOs....I know, I know...passive stuff of the shelf will be crap, but I still wonder.....
Still deciding on what to do with my 103's...might stay with the pre-designed RLH that fostex recommends.
Cheers.
This is one of the reasons I may stick to the challenge od single drivers.
I am considering making a similar folded TQWT or TL for the JBL60 (the 6" version of the 40's). I can get a pair for RS. 1250 and the quoted range is 90hz-19khz. It would be interesting to put them through a Speaker WKSP test to see what they really are.
I also saw a blaupunkt set of surface mount tweets and a matched pair of XOs....I know, I know...passive stuff of the shelf will be crap, but I still wonder.....
Still deciding on what to do with my 103's...might stay with the pre-designed RLH that fostex recommends.
Cheers.
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