1) I don't know.(1) Is my current measurement system really a "USB mike"; I have a ECM8000 mic + Presonus Audiobox USB which is a real mic/line mixer but USB connected. I suspect this is a case of "rather than research it, why don't you just f******g try it and see if it works????" 😀
(2) I have a vague grasp of phase (one frequency leads or lags another, the reference), and it is not the same as delay. I am still foggy on group delay and excess, minimum and wrapped/unwrapped phase (when you want to give phase as a gift ?)
(3) Granted the Unity | Synergy is an odd case; analog x-over shifts phase 90 degrees ahead or back, other values depending on order of x-over, does this still apply with active EQ or DSP (MiniDSP)?
(4) A chamber (port) such as this design uses, is an acoustic low pass. I am still wondering how to model this in HornResp (I'm taken aback at the prospect of learning acabak 🙂 ) ... and this shifts phase too ....?
Theory has its place, but experimentation is more fun. I mean, sure the military has been studying EM weapons for decades, nothing (apparently) practical has come from it, but the laser is useful for many tasks, even short of Star Trek phaser technology. But nothing will ever equal the joy of discovery a boy has upon first learning to use a magnifying glass and the Sun's rays to vaporize hapless ants
2) The terms are explained in the REW manual and various other places.
3) The 90 degree lag per pole (order, capacitor, coil) applies to active IIR filter (the usual) based DSP, although can be eliminated with FIR filters.
4) There are provisions in the "offset driver"(OD) option, and the more current releases also have "multiple entry" options. APT is the area of the port, VTC is volume of throat chamber, the cone shaped volume between the cone and the horn wall. There is a "driver front volume" calculator which can help determine the volume of the throat chamber. An acoustic low pass does shift phase, because the HF driver is physically behind the offset drivers, the phase lag may be compensated for.
Art
It's plausible that USB interfaces have a digital buffer and use queue based serial data transfer as well as sharing with peripherals, so not necessarily time critical operation. It's reasonable to switch off all background operations, disconnect networks etc and restart your system before measuring, but this is not a guarantee. I prefer to run a mic to an inboard sound card (through a pre).
Non-ligneous materials
I've tried a loopback ("calibrate soundcard") but not sure if it impacts the two readings I've taken yet...will screw with it more 🙂
On a (slighly) sillier note, which is what I typically dispense here, I of course plan to continue with non-standard (e.g. plywood) materials for my creations. Xrk971, specialist in foamcore, heck even he has been known to resort to wood in a pinch 😀
I am still working on my supply of "coroplast" (harvested advertising signs) and I am not averse to bracing with wood at times. Yes, they make a passable waveguide, but jury still out on whether a test box for a 12" sub will work. If it does I will have something to brag about, a downscale version of the Redneck Bucket Sub that (I guess) works.
Oh yeah, the silly part. I'm an advocate of using found items (or sizes) as much as possible, not always a success as my hollow core door sub of a few years ago proved. Still, here's a possible pre-made horn I found. I doubt I'll buy one but you are welcome to try 🙂
They are < $200 and double as a vat for biodiesel or making beer 🙂
Weltersys said: The prototype horn was constructed in less than an hour from cardboard and tape (a plastic jug for the back chamber, I'd expect even better results with more attention to detail.
More details in post #860 here:
A Bookshelf Multi-Way Point-Source Horn
Art"
Long live jerry-rigging!
I've tried a loopback ("calibrate soundcard") but not sure if it impacts the two readings I've taken yet...will screw with it more 🙂
On a (slighly) sillier note, which is what I typically dispense here, I of course plan to continue with non-standard (e.g. plywood) materials for my creations. Xrk971, specialist in foamcore, heck even he has been known to resort to wood in a pinch 😀
I am still working on my supply of "coroplast" (harvested advertising signs) and I am not averse to bracing with wood at times. Yes, they make a passable waveguide, but jury still out on whether a test box for a 12" sub will work. If it does I will have something to brag about, a downscale version of the Redneck Bucket Sub that (I guess) works.
Oh yeah, the silly part. I'm an advocate of using found items (or sizes) as much as possible, not always a success as my hollow core door sub of a few years ago proved. Still, here's a possible pre-made horn I found. I doubt I'll buy one but you are welcome to try 🙂
They are < $200 and double as a vat for biodiesel or making beer 🙂
Weltersys said: The prototype horn was constructed in less than an hour from cardboard and tape (a plastic jug for the back chamber, I'd expect even better results with more attention to detail.
More details in post #860 here:
A Bookshelf Multi-Way Point-Source Horn
Art"
Long live jerry-rigging!
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And now matching subwoofer...
Rev 0 of the sign sub is a "go"; more bracing probably needed. Not too many rattles or buzzes, amazing as the lid isn't affixed yet. Innards are a combination of triangles of same coroplast and wood scraps for glue blocks, strengthening and general "try one here and see if the vibration stops" tweaking 😀
I rather like recycling signs like this. This is an election year so I should be able to accumulate a large amount of raw material. I hope I can stay out of jail this time 🙄
I'm going to explore "maker" and recycling, repurposing ideas... Maybe I can share my ideas elsewhere. I know it'll take me away from DIYaudio for a while but I know you guys will understand 😀
Rev 0 of the sign sub is a "go"; more bracing probably needed. Not too many rattles or buzzes, amazing as the lid isn't affixed yet. Innards are a combination of triangles of same coroplast and wood scraps for glue blocks, strengthening and general "try one here and see if the vibration stops" tweaking 😀
I rather like recycling signs like this. This is an election year so I should be able to accumulate a large amount of raw material. I hope I can stay out of jail this time 🙄
I'm going to explore "maker" and recycling, repurposing ideas... Maybe I can share my ideas elsewhere. I know it'll take me away from DIYaudio for a while but I know you guys will understand 😀
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As far as your usb device goes if you are using it for mic in/speaker out (in other words on the same clock) then it will work just fine. If you are using some other dac for your speaker output then it may or may not work. I use an M-Audio usb mic pre, but my speaker dac is a separate firewire device. If I work quickly I can use the physical loopback on rew to look at phase between different drivers. However, if I measure the tweeter and a few minutes later measure the mid all bets are off. If I do them quick in succession I'm gtg.
A "digital" time lock like is used in Holm impulse is on the REW dev's to-do list....for that matter you could use Holm but I personally don't have any luck with the time lock due to the way I have to route the audio on my pc.
A "digital" time lock like is used in Holm impulse is on the REW dev's to-do list....for that matter you could use Holm but I personally don't have any luck with the time lock due to the way I have to route the audio on my pc.
I made another trial run at playing with the phase on my "left" speaker this morning. I can't tell any difference in the read-outs that REW gives. I can easily see that the phase (unwrapped) goes "south" around my crossover frequency 🙁
What I tried this morning were several sweeps but with varying time delay to the mids and I watched how whacked the phase was around the x-over. I settled on (I think) 0.12 msec as the cleanest looking.
Other threads speak of "dual channel" measuring but I have seen no mention on how to do this in REW.
If you're still willing to give me a lesson in how to properly measure time delay or phase (asssuming my gear can do it), you are welcome to. I concede the point that my campaign sign waveguides are probably not real coherent, but I still should be able to measure how disastrous they are 😀
What I tried this morning were several sweeps but with varying time delay to the mids and I watched how whacked the phase was around the x-over. I settled on (I think) 0.12 msec as the cleanest looking.
Other threads speak of "dual channel" measuring but I have seen no mention on how to do this in REW.
If you're still willing to give me a lesson in how to properly measure time delay or phase (asssuming my gear can do it), you are welcome to. I concede the point that my campaign sign waveguides are probably not real coherent, but I still should be able to measure how disastrous they are 😀
Still confused.
After many many hours of studying posts here, reading the patents and driving myself (and you other guys too) nuts with my musings, I am little closer to understanding the evolution from Danley's Unity to Synergy. As far as I can tell they are the same thing but then I'm not an audio engineer 🙂 Even in his patent, he compares the TDA-1 (Unity), and mods it (how?) and gets much better results, and all that has changed is port positions and shapes of ports? Is this because he now uses the Frammistan or whatever it's called? 😀
After many many hours of studying posts here, reading the patents and driving myself (and you other guys too) nuts with my musings, I am little closer to understanding the evolution from Danley's Unity to Synergy. As far as I can tell they are the same thing but then I'm not an audio engineer 🙂 Even in his patent, he compares the TDA-1 (Unity), and mods it (how?) and gets much better results, and all that has changed is port positions and shapes of ports? Is this because he now uses the Frammistan or whatever it's called? 😀
The who, what are you referring to??
Right, the Synergy concept except refined for increased performance is the same as the Unity, which AFAIK is 'owned' by Servo-Drive where TD worked at the time he invented it.
You want to optimize the mids, etc., chambers to the max, study up on high compression cylinder head, piston, exhaust design systems, though unfortunately, making a driver with the physical characteristics of a high performance metal piston and associated driving parts will be the real challenge 😉, but it will show you how to maximize, evenly distribute the compression stroke of whatever driver you choose at 'x' port offset, which I assume is how TD is doing it these days. That, or by now he's tried enough variations to have a clue what works well enough, so has a good rule-of-thumb to make short work of it.
GM
Right, the Synergy concept except refined for increased performance is the same as the Unity, which AFAIK is 'owned' by Servo-Drive where TD worked at the time he invented it.
You want to optimize the mids, etc., chambers to the max, study up on high compression cylinder head, piston, exhaust design systems, though unfortunately, making a driver with the physical characteristics of a high performance metal piston and associated driving parts will be the real challenge 😉, but it will show you how to maximize, evenly distribute the compression stroke of whatever driver you choose at 'x' port offset, which I assume is how TD is doing it these days. That, or by now he's tried enough variations to have a clue what works well enough, so has a good rule-of-thumb to make short work of it.
GM
Haven't tried it yet because only few days ago myself got a analog mic to run from same clock so up to now had run from a USB mic.
It seems like following settings need attention:
In "Preferences" at tab "Analysis" tick "Use loopback as timing reference" and at same lets say you measure at left channel I/O then connect a physical loop cable from right channel output to input.
Here what REW says in that menu's help:
In "Preferences" at tab "Soundcard" attention is needed too, if running Java drivers set which channel is used to measure and if running ASIO driver set which channel to use as timing reference.
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BYRTT's instructions show you how to set up the loopback, but it doesn't tell you how to actually use it.
1) Measure the tweeter (use the physical loopback for every measurement)
2) Measure the mid
3) For the tweeter: Impulse tab/Control tab/Estimate IR delay
4) Input the delay given for "t=0 offset (ms) and hit enter
5) Enter the same delay value in the "t=0 offest (ms)" for the mid and hit enter
What this does is it sets the tweeter to 0 time (you should notice that before you enter the delay it's not at 0, this is the time of flight) and the same offset puts the mid at the correct time in relation to the tweeter. This will show you the phase between the two sections for xo work. For further fine tuning I'll put the cursor at a freq on the "SPL and phase" plot near the xo where the phase is relatively flat near the xo, ie not wrapping. I'll unwrap the phase for both sections at this position.
If you're handy you can likely work out the xo/eq and any delay needed to get the system aligned without making any more measurements other than to check your work......if REW's eq works the same as the eq you're using. If you're working with a passive xo you're on your own, but with passive xo design sw this time lock business isn't necessary.
The process to do this digitally in Holm is easier but like I said doesn't work in my case so I won't detail instructions for that, but they can be found easily.
1) Measure the tweeter (use the physical loopback for every measurement)
2) Measure the mid
3) For the tweeter: Impulse tab/Control tab/Estimate IR delay
4) Input the delay given for "t=0 offset (ms) and hit enter
5) Enter the same delay value in the "t=0 offest (ms)" for the mid and hit enter
What this does is it sets the tweeter to 0 time (you should notice that before you enter the delay it's not at 0, this is the time of flight) and the same offset puts the mid at the correct time in relation to the tweeter. This will show you the phase between the two sections for xo work. For further fine tuning I'll put the cursor at a freq on the "SPL and phase" plot near the xo where the phase is relatively flat near the xo, ie not wrapping. I'll unwrap the phase for both sections at this position.
If you're handy you can likely work out the xo/eq and any delay needed to get the system aligned without making any more measurements other than to check your work......if REW's eq works the same as the eq you're using. If you're working with a passive xo you're on your own, but with passive xo design sw this time lock business isn't necessary.
The process to do this digitally in Holm is easier but like I said doesn't work in my case so I won't detail instructions for that, but they can be found easily.
Thanks Nate. I have not yet tried your above suggestions but I did so some more measuring, the tweet and mids separately and then comparing the impulses and step. I then did a real time measurement with band limited pink noise (500 Hz-1000 Hz) because both tweet and mid have similar amplitude (frequency) and group delay doesn't get stupid until > 1 KHz with mids; best null was with HIGHS delayed about 0.12 msec. Completely counter-intuitive; you are supposed to delay the mids, I thought, because they are closer to the mic/listener.
It's results like the above that sometimes make me regret that I gave up drinking 😀
It's results like the above that sometimes make me regret that I gave up drinking 😀
[Jackass Mode = ON]
I'm having modest success with the sub, so far. The thought ("brain seizure" would probably be a more accurate term) occured to me: since I am on a recycling, repurposing kick (sounds better than "pilfering advertising signs and making dubious speaker enclosures") why not try and build a proper LF horn of same? I know that to hit the lowest notes you need a really, really big horn that wouldn't easily fit in most houses, never mind the WAF (I'm single). Here's an "if only!" idea, that would still be using advertising signs. A true LF horn, especially conical, demands long and large. Thus would be easiest if very large sheets of material are available. Hmmm....
[Jackass mode = OFF]
I * am * going to consider making a FAST (?) -- I am intrigued by the Travesty 2.x mids/highs, but they need a low end. Technically I still have the Frankenclosure sub but why not a pair of 12" subs (drivers already on hand, even if they don't match, who cares?) I will have to cross them higher. I'm stating to see the wisdom of the 15" sub right below a Unity | Synergy type horn on top 🙂
I'm having modest success with the sub, so far. The thought ("brain seizure" would probably be a more accurate term) occured to me: since I am on a recycling, repurposing kick (sounds better than "pilfering advertising signs and making dubious speaker enclosures") why not try and build a proper LF horn of same? I know that to hit the lowest notes you need a really, really big horn that wouldn't easily fit in most houses, never mind the WAF (I'm single). Here's an "if only!" idea, that would still be using advertising signs. A true LF horn, especially conical, demands long and large. Thus would be easiest if very large sheets of material are available. Hmmm....
[Jackass mode = OFF]
I * am * going to consider making a FAST (?) -- I am intrigued by the Travesty 2.x mids/highs, but they need a low end. Technically I still have the Frankenclosure sub but why not a pair of 12" subs (drivers already on hand, even if they don't match, who cares?) I will have to cross them higher. I'm stating to see the wisdom of the 15" sub right below a Unity | Synergy type horn on top 🙂
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Stay on the wagon man, you're right on track 😉
Having to delay the output for the tweeter is common in a Synergy. The mids are physically forward of the hf, but the acoustic lp creates delay. On my "mini-Synergy" I built a few months back with a compression driver and 3 4" cone mids the hf was delayed about .5ms iirc.
Nate, thanks. That is reassuring. They sound fine now, as they did with all my other tweak settings 😱
I was on the wagon for decades until I found it was the one being pulled by a team of Clydesales 😀
I was on the wagon for decades until I found it was the one being pulled by a team of Clydesales 😀
Pleasant evening bike ride and bumper sign harvest 🙂
Sunday evening's bike ride was a few miles west into a sunset and back home enjoying the full moon. Sunday night is my peak "sign harvesting" night. I am kind enough to not remove the housing development's signs until the weekend is over 🙂 I got so many I could barely carry them home on my rear rack. I'd post a photo but it's just a pile of coroplast signs, for crying out loud 😀
I did just get a possibly not silly idea: instead of a folded horn (BFD, that was done before most of us were born!) how about a foldable horn? Some quick googling shows that, yes, others have created foldable (paper) speakers. A comapny named Origiaudio did it around 2009. Curiously, I can't find the product on their web site now. But I want something more than an Ipod connected one watt speaker.
Mind you, I know little of pro audio or PA systems. Duh, I can assume that most of it is portable but I am thinking a coroplast waveguide. Surely this has been done? If you want a Synergy | Unity one it will have to be DIY though.
Ideas are easy, but willl they work in the real world?
Memo to self: has anyone patented the battery-powered battery-charger yet? 😀
* Ahem * moving right along...when just throw away plastic material + adhesives is needed, why not experiment? Now that would be cool: a collapsible and easily toted set of (loud) horns to blare from your battery powered amp and player in a public place 😛
Sunday evening's bike ride was a few miles west into a sunset and back home enjoying the full moon. Sunday night is my peak "sign harvesting" night. I am kind enough to not remove the housing development's signs until the weekend is over 🙂 I got so many I could barely carry them home on my rear rack. I'd post a photo but it's just a pile of coroplast signs, for crying out loud 😀
I did just get a possibly not silly idea: instead of a folded horn (BFD, that was done before most of us were born!) how about a foldable horn? Some quick googling shows that, yes, others have created foldable (paper) speakers. A comapny named Origiaudio did it around 2009. Curiously, I can't find the product on their web site now. But I want something more than an Ipod connected one watt speaker.
Mind you, I know little of pro audio or PA systems. Duh, I can assume that most of it is portable but I am thinking a coroplast waveguide. Surely this has been done? If you want a Synergy | Unity one it will have to be DIY though.
Ideas are easy, but willl they work in the real world?
Memo to self: has anyone patented the battery-powered battery-charger yet? 😀
* Ahem * moving right along...when just throw away plastic material + adhesives is needed, why not experiment? Now that would be cool: a collapsible and easily toted set of (loud) horns to blare from your battery powered amp and player in a public place 😛
I concede the point, oh mediocre minstrel 🙂
Actually I recall the concept from an ancient MAD magazine (1960s?) spoof on the old mail order catalogues. Now if you see a D-cell powered D-cell charger... 🙂
One joke I do claim as mine is the daffy-nition: decelerate: (V) to become a flashlight battery.
Actually I recall the concept from an ancient MAD magazine (1960s?) spoof on the old mail order catalogues. Now if you see a D-cell powered D-cell charger... 🙂
One joke I do claim as mine is the daffy-nition: decelerate: (V) to become a flashlight battery.
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Actually relevant to (not) understanding Unity :
Somewhere it says that (for example) the HF driver can't "see" the ports for the Mid(s) if the lengths are properly calculated. If this is true, then why is it a big deal to have the ports of a certain minimal size and/or shape? I'm not saying a smooth bore isn't a good thing, but it appears most of the effort is put into having a very smooth start at the throat, especially if going from round to rectangular. I'm not suggesting we put a windmill in the horn at the Mids port, but I want to understand better why we shouldn't (say) have a fully-exposed driver cone in the wall? (Yes, this assumes one would not use the acoustic LP of a chamber + port.)
Somewhere it says that (for example) the HF driver can't "see" the ports for the Mid(s) if the lengths are properly calculated. If this is true, then why is it a big deal to have the ports of a certain minimal size and/or shape? I'm not saying a smooth bore isn't a good thing, but it appears most of the effort is put into having a very smooth start at the throat, especially if going from round to rectangular. I'm not suggesting we put a windmill in the horn at the Mids port, but I want to understand better why we shouldn't (say) have a fully-exposed driver cone in the wall? (Yes, this assumes one would not use the acoustic LP of a chamber + port.)
Actually, the crude POC I did had mostly exposed drivers [2:1 CR to primarily cover the surrounds], but the piezo had a very focused beam in a technically too wide a WG, so 'exposed' was mostly moot.
Again, this type of alignment is little different than a MTM or WMTMW on a baffle in that it's all about doing what's required to meet the needs of the app and prosound designs aren't necessarily needed or even wanted in some cases for HIFI/HT apps.
GM
Again, this type of alignment is little different than a MTM or WMTMW on a baffle in that it's all about doing what's required to meet the needs of the app and prosound designs aren't necessarily needed or even wanted in some cases for HIFI/HT apps.
GM
Recent activity, mostly serious even!
GM, thanks for the comment. I am barely aware of the MTMW etc. projects since I have yet to meddle in OB or "build a normal speaker" world 🙂
On a sort-of similar track, however, I will probably not build this, but I believe the following is actually true to the Unity patent "180 degree (flat) horn" case:
Being (still) the owner of three working pairs of Bose 901 (I, II) plus various parts therefrom, years ago I'd bought a pair of Selenium ST-200 "super tweeters" intending to mate them to a pair of 901s. Never happened. I have played with them some, but really done nothing. This stupid idea occured to me to day:
You could take a stock "original" 901, disconnect 5 of the 9 drivers, leave one quad wired on the rear. Then stick a small tweeter in the center of it. The center to center distance is ~8 cm -> x-over of about 1075 Hz. Viola. You have a bastard Unity monitor (or a MMMM with a T in the center?); obviously you'd have to rewire the guts of the 901 and have active EQ, two channels of amplification, etc. But wouldn't it be basically a "virtual point source"?
Any venerable (or is that "venerial" 🙂 ) speaker like the 901 that has been around so long has had all kinds of DIY mods, no doubt driven by a desperate audio-fool trying to make the components sound like something other than a 901 🙂 ... My above idea is kind of dumb, I readily admit, but re-using the CTS era drivers in other designs is better recycling. This is, in fact what I did with my Travesty 2.x so far. Another idea that would seem possible, but probably not worth pursuing, would be thus:
No law says that, say if I had a huge collection of identical drivers (such as the CTS from the paleo-901s) that they only would have to be used for the mid ranges. Of course, using them for tweeters or woofers is sub-optimal, but then so was using them in the original Bose 901 🙂 ... but why couldn't a bigger "ring" of the drivers be used in the woofer band area, you could add a lot more of them due to the much greater distance between mids <> woofers. This would, of course be a three-way Unity | Synergy, just that you'd have identical drivers doing duty in the mid and bass passbands.
What I really have done today:
I am working on the Travesty pair, so I had no choice but to hook up a pair of normal 901s and listen. They are listenable but I already miss my "point source" of the Travesty 2.X !!! Yes, even my ***/2 version of The Master's (Danley or xrk971, I am not sure whom) 🙄
I tried a pair of the "floor sweepings" MCM $3, er, "transducer" is about the only noun I would grant to that abomination 🙂 and to no one's surprise, the results are total disaster. Ten watts per channel my $$$!!! Not even any mid-bass. Yuk.
Further surgery on the 2nd Travesty 2.x to swap out a buzzing CTS driver and put in a good(er) one. I still have three spares so don't have to pillage my healthy 901 cabs just yet 😀
Dreaming dept: I was reading up on BMS drivers last night. Nice web site. The only US importer had some more info. One tidbit I found interesting is that BMS has licenced some manufacturer in the USA but they still have to import the diaphragm from Der Fatterland because the American Co. could not make that part. So just like BMWS, even fine German engineering is nowadays partly made here in Amerika.
I think they've been mentioned some here on DIYAudio, but BMS and no doubt others, offer various "point source" cone or even compression drivers. I am assuming these still need a waveguide; has anyone tried these? Not cheap, but ready made, und mit Deutsche Teknik no doubt a superior product. Rather takes the fun out of DIY tho. 🙁
GM, thanks for the comment. I am barely aware of the MTMW etc. projects since I have yet to meddle in OB or "build a normal speaker" world 🙂
On a sort-of similar track, however, I will probably not build this, but I believe the following is actually true to the Unity patent "180 degree (flat) horn" case:
Being (still) the owner of three working pairs of Bose 901 (I, II) plus various parts therefrom, years ago I'd bought a pair of Selenium ST-200 "super tweeters" intending to mate them to a pair of 901s. Never happened. I have played with them some, but really done nothing. This stupid idea occured to me to day:
You could take a stock "original" 901, disconnect 5 of the 9 drivers, leave one quad wired on the rear. Then stick a small tweeter in the center of it. The center to center distance is ~8 cm -> x-over of about 1075 Hz. Viola. You have a bastard Unity monitor (or a MMMM with a T in the center?); obviously you'd have to rewire the guts of the 901 and have active EQ, two channels of amplification, etc. But wouldn't it be basically a "virtual point source"?
Any venerable (or is that "venerial" 🙂 ) speaker like the 901 that has been around so long has had all kinds of DIY mods, no doubt driven by a desperate audio-fool trying to make the components sound like something other than a 901 🙂 ... My above idea is kind of dumb, I readily admit, but re-using the CTS era drivers in other designs is better recycling. This is, in fact what I did with my Travesty 2.x so far. Another idea that would seem possible, but probably not worth pursuing, would be thus:
No law says that, say if I had a huge collection of identical drivers (such as the CTS from the paleo-901s) that they only would have to be used for the mid ranges. Of course, using them for tweeters or woofers is sub-optimal, but then so was using them in the original Bose 901 🙂 ... but why couldn't a bigger "ring" of the drivers be used in the woofer band area, you could add a lot more of them due to the much greater distance between mids <> woofers. This would, of course be a three-way Unity | Synergy, just that you'd have identical drivers doing duty in the mid and bass passbands.
What I really have done today:
I am working on the Travesty pair, so I had no choice but to hook up a pair of normal 901s and listen. They are listenable but I already miss my "point source" of the Travesty 2.X !!! Yes, even my ***/2 version of The Master's (Danley or xrk971, I am not sure whom) 🙄
I tried a pair of the "floor sweepings" MCM $3, er, "transducer" is about the only noun I would grant to that abomination 🙂 and to no one's surprise, the results are total disaster. Ten watts per channel my $$$!!! Not even any mid-bass. Yuk.
Further surgery on the 2nd Travesty 2.x to swap out a buzzing CTS driver and put in a good(er) one. I still have three spares so don't have to pillage my healthy 901 cabs just yet 😀
Dreaming dept: I was reading up on BMS drivers last night. Nice web site. The only US importer had some more info. One tidbit I found interesting is that BMS has licenced some manufacturer in the USA but they still have to import the diaphragm from Der Fatterland because the American Co. could not make that part. So just like BMWS, even fine German engineering is nowadays partly made here in Amerika.
I think they've been mentioned some here on DIYAudio, but BMS and no doubt others, offer various "point source" cone or even compression drivers. I am assuming these still need a waveguide; has anyone tried these? Not cheap, but ready made, und mit Deutsche Teknik no doubt a superior product. Rather takes the fun out of DIY tho. 🙁
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