If I only knew then what I know now...
My name is Daniel and I am an audio forum addict...
I lurk, a lot.
On multiple forums. And I recognize many of you as contributors from other places.
This thread strikes me as intimately relevant for most of our home listening environments, so I check in regularly.
And I have collected more drivers, horns etc. than I care to admit.
I think we all fall into a similar trap; paralysis of analysis, letting perfect get in the way of good (didn't someone just say this somewhere recently ?). There is so much music at our fingertips these days, and the ultimate goal should be the act of using our ears.
If i sold all of my audio bits-n-pieces and was starting from scratch, I am 99% certain I would buy or clone the JBL 1400 Array. Not technically a 2 way, but...
My name is Daniel and I am an audio forum addict...
I lurk, a lot.
On multiple forums. And I recognize many of you as contributors from other places.
This thread strikes me as intimately relevant for most of our home listening environments, so I check in regularly.
And I have collected more drivers, horns etc. than I care to admit.
I think we all fall into a similar trap; paralysis of analysis, letting perfect get in the way of good (didn't someone just say this somewhere recently ?). There is so much music at our fingertips these days, and the ultimate goal should be the act of using our ears.
If i sold all of my audio bits-n-pieces and was starting from scratch, I am 99% certain I would buy or clone the JBL 1400 Array. Not technically a 2 way, but...
According to Dr. Geddes IMD is over stated by some and I think he means within proper design technique you'll not have an issue...We've had a few people chime in not too long ago in this thread who have the jbl m2 and no complaints of IMD...though I am not certain if they had there systems tuned flat to 30hz as I intend...The Strauss also is accepted by mastering engineers with no subwoofer as Mr.. Strauss pushes the idea to not use one, as more drivers cause more issues....
So how do I feel? I think that with a large enough woofer vs a low enough playback (Domestic?)....IMD is not an issue...I feel that for compression drivers IMD seems to be less of an issue concerning domestic levels...as I can play the Axi2050 with no crossover and levels reached loud enough while distortion figures raised though I never found xlim...with or without horn....I have not idea where xlim is and I am glad that it is beyond the dynamic needs of domestic volume. Its hard to say when or where IMD may have become an issue because we all know that there is resolution in directivity and with my horn attached directivity is raised.
Plenty more experimenting needs to be done, on my end. Understanding how to get it to play best is a good focus and no one has ever argued against lowering excursion lol
I know I didn't need a subwoofer per say and I have dual sets of 18's but this system is meant to be a flagship model. Decreasing excursion is the goal period...I like bass too, so outside of analytical work (sound engineering) I enjoy movies and video games as well and the tactile experience of bass is fun.
I've personally never heard a large 15" horned twoway outside the Altecs which aren't made for sub bass
I think one would do well with a 15" + Horn
Hindsight? maybe two 12m's in a MTM for tops sitting on a large woofer
I feel my theory of small horns being the midpoint between horn/waveguide is correct. A 350hz or smaller horn seems to have a small enough resonate that playing down to tuning is not detrimental on that level but I set myself up to succeed by buying the largest Sd compression I could afford. Tuning is a more sophisticated thing than at first glance..I think two different sized 2" horns could be tuned to a certain note and the resonate character will still be unique so maybe I am blessed to have come across the e-tractrix? My 350hz jmlc horns are much larger....a long line is going create decay no different than a long undamped transmission line but I have not yet converted them to 2" (they are 1.5") I could use it without a horn and cross lower than one would think is how I feel at the moment (for nearfield)....without a waveguide I cannot comment too much on that aspect but I would think a waveguide would help tame the impedance swings I seen measuring it with nothing on it.
During modelling I purposely design most things are one channel with the idea that if I strived for the desired system performance in one channel, that 2 channels would be the nail in the coffin....I did not realize how well this approach would work vs what type of loudness potential I was creating thats for sure...I am slowly but surely building the cabs...so the grand view of this system is not available of yet....
I learned the most studying TL, debating here and with Martin King on his Fb group. I also learned why the circle of confusion exist still to this day after sharing what I'd learned here on a mastering group and getting banned for 9 days only to return (more politely) and still be gaslighted for several threads until other more intelligent mastering engineers show'd up and confirmed my knowledge of design....sad thing is I am no expert....and I embarrassed several professionals trying to push their weight around for no reason other than wanting to be right. These things are recorded in text.....Truth will stand and a lie will always fall.
Can a two way cover the full spectrum at high volume? Define high volume and full spectrum and low distortion lol....In a domestic setting? Nearfield? If you will accept higher thd then 1-2% at the bottom yes.....I'm still sand bagging!...looking at simulation in half space...looking at one channel simulations of sealed enclosures....of dual 15m and single 18H+
Whats left on the table? Room gain...the second channel...higher efficiency of vented design
If you throw farfield in there then things get more difficult but my design is for nearfield which is why I focused to hard at getting below KA=2 XO
With a design like this large two way on top of subs....its 3 channels...removing the heavy lifting from the now midbass woofer yet increasing efficiency down low with large sd subwoofers and if a large format 2 way is just getting by....this is exceeding all expectations.
I keep forgetting some people have lower bass expectations...playing to 20hz while doing midrange will probably expose the weakness of having sub bass and mid range on the same driver...
I made those assumptions above with 30hz in mind which is about all you need for most music
Adding the “to 20hz” expectations....No....you cannot cover 20-20khz, high volume, low distortion with a 2 way
Two different full spectrums
Flat to 30hz yes
Flat to 20hz no
I’m still making educated guesses but I think this answer will be found acceptable by the people I’ve learned from here. Because if the nature of bass (excursion, higher power response) it just makes sense to want to keep that part of the signal away from anything touching midrange. I feel like a top shelf, large diaphragm, 2” exit, compression driver along with crossing over low on a horn to a large sd woofer....is the cheat sheet to plug and play high sq (Strauss 2.1) as long as FIR and time alignment of all drivers are apart of the recipe
Buying all “all star” drivers definitely is good idea though this may be a trait of ACOUSTIC ELEGANCE
While simulating with the 15m a single 18h+ I had the feeling that John designed these drivers to be mated. The Axi2050 may be one the best compression drivers of our time but I’m just new purchase biased right? I only found two reviews of it before my purchase, they both left it for the radian950BE...I have since heard others say it is in another league above Radian regarding smoothness of midrange response....having ideas to try and build a large horn to see if I can cross at 200hz.....the first two reviewers already confirmed it plays lower than the radian950BE so it suits me.
I made those assumptions above with 30hz in mind which is about all you need for most music
Adding the “to 20hz” expectations....No....you cannot cover 20-20khz, high volume, low distortion with a 2 way
Two different full spectrums
Flat to 30hz yes
Flat to 20hz no
I’m still making educated guesses but I think this answer will be found acceptable by the people I’ve learned from here. Because if the nature of bass (excursion, higher power response) it just makes sense to want to keep that part of the signal away from anything touching midrange. I feel like a top shelf, large diaphragm, 2” exit, compression driver along with crossing over low on a horn to a large sd woofer....is the cheat sheet to plug and play high sq (Strauss 2.1) as long as FIR and time alignment of all drivers are apart of the recipe
Buying all “all star” drivers definitely is good idea though this may be a trait of ACOUSTIC ELEGANCE
While simulating with the 15m a single 18h+ I had the feeling that John designed these drivers to be mated. The Axi2050 may be one the best compression drivers of our time but I’m just new purchase biased right? I only found two reviews of it before my purchase, they both left it for the radian950BE...I have since heard others say it is in another league above Radian regarding smoothness of midrange response....having ideas to try and build a large horn to see if I can cross at 200hz.....the first two reviewers already confirmed it plays lower than the radian950BE so it suits me.
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A nice summary of your experiences so far, camplo!
The following doesn't apply to you
Regarding the thread title, I think it is certainly possible with the acceptance of some minor compromises.
A compromise has to be made between low freq. extension and crossover frequency. In conjunction it should be determined to which extent excursion can be limited.
Personally, I am a supporter of the view that a decent 15" low Xmax (mid)woofer provides enough low freq. extension for an average (European) room. So I won't look for "flat to 30Hz or below".
Forget it, if only for room modes that may spoil the low-end party.
-3 dB around 50 Hz seems a nice target > a gradual downward slope from about 100-150Hz, depending on the compression driver and horn. In general you'll end up with an in-room response down to at least 40Hz and most likely (much) lower. In practice, depending on the enclosure (which cannot be tiny), the 15" cone should vibrate instead of move, thus minimizing all kinds of undesirable artefacts (IMD, port resonances/ringing etc.).
The crossover frequency must be somewhere between 500 and 1000Hz. But you should consider the woofer's response > 500Hz. If the impedance starts to get wobbly, that specific woofer might not be the best candidate for the job.
These are just a few general considerations and there's obviously much more to the design of an efficient 2 way, such as directivity, phase etc. etc.
Many relevant topics were discussed previously and I'll probably dump some additional in-depth literature about specific topics in the near future.
The following doesn't apply to you
Regarding the thread title, I think it is certainly possible with the acceptance of some minor compromises.
A compromise has to be made between low freq. extension and crossover frequency. In conjunction it should be determined to which extent excursion can be limited.
Personally, I am a supporter of the view that a decent 15" low Xmax (mid)woofer provides enough low freq. extension for an average (European) room. So I won't look for "flat to 30Hz or below".
Forget it, if only for room modes that may spoil the low-end party.
-3 dB around 50 Hz seems a nice target > a gradual downward slope from about 100-150Hz, depending on the compression driver and horn. In general you'll end up with an in-room response down to at least 40Hz and most likely (much) lower. In practice, depending on the enclosure (which cannot be tiny), the 15" cone should vibrate instead of move, thus minimizing all kinds of undesirable artefacts (IMD, port resonances/ringing etc.).
The crossover frequency must be somewhere between 500 and 1000Hz. But you should consider the woofer's response > 500Hz. If the impedance starts to get wobbly, that specific woofer might not be the best candidate for the job.
These are just a few general considerations and there's obviously much more to the design of an efficient 2 way, such as directivity, phase etc. etc.
Many relevant topics were discussed previously and I'll probably dump some additional in-depth literature about specific topics in the near future.
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Joseph Crowe developed a 2 way that would comply with this thread.
It's based on RCF drivers, that I have also come to appreciate.
The woofer is a bit heavy duty for my taste, but at least η0 > 2.5 %, what I consider a kind of benchmark value for mid-range suitability and fitness for low power amps.
A SET or low power Class A amp won't breathe life into an inefficient woofer.
It's the exception rather than the rule that the response matches the one in the specsheet, despite the fact that the horns are completely different. The few subtle resonances can probably be further reduced by a simple Crowe-mod: putting a small amount of 30ppi open-cell foam into the rear chamber so that it gently presses on the center of the diaphragm.
It's based on RCF drivers, that I have also come to appreciate.
The woofer is a bit heavy duty for my taste, but at least η0 > 2.5 %, what I consider a kind of benchmark value for mid-range suitability and fitness for low power amps.
A SET or low power Class A amp won't breathe life into an inefficient woofer.
It's the exception rather than the rule that the response matches the one in the specsheet, despite the fact that the horns are completely different. The few subtle resonances can probably be further reduced by a simple Crowe-mod: putting a small amount of 30ppi open-cell foam into the rear chamber so that it gently presses on the center of the diaphragm.
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Thank you for appreciating this thread and chiming in! I looked at the 1400 Array BG was like "just when you thought you'd seen it all" different common models slip by me all the time.... I'm glad people chose to share things like this here.
I think you are thinking with sense...this system is meant to be sorta gaudy in effort to exaggerate the price to performance ratio of DIY in the shadow of the great oppression of some manufactured speakers...its funny that people think I have waivered on my design...Did I really waiver or did I turn this thread into a book of "what ifs"...this thread represents the power of collective intelligence along with some guidance of some of the brightest minds...any new DIYer could read this thread and know so much and go on to build something similar. You should know I purposely designed this thread as you see it, trying to cover every crazy "what if" I could think of. After reading a thread like this I think one could basically have a mini session of analysis paralysis through my eye and save themselves a trip or two or four lol. I am trying to not finish this system and think later....why didn't I think of that!...this is inevitable surely but on what level?
When I started this thread, I wanted a completely sealed system. Thats what I am assembling....I did my best to try and convince myself to do anything but, as a way to prove sealed is what I really wanted. I made the connection between vented and essentially 2 sources that gave the output (for SQ purposes) I wanted down low and then added another 18h+ to replace the vent, in order to remain sealed and achieve that output. From there I struggled to find a way to fit all sources as close as possible and on the front baffle until the PPSL configuration emerged solving more problems than I asked it too while creating a few others not related to SQ.
I agree that the ears are at play, but for what this system is leveled at I intend to use it for mastering music. The saying goes ears lie measurements don't
Thanks Ro808 for Joseph Crowe ES600 link & picture. I want to mount the 1200-17khz horn outside the Bass box. 22XT. I cannot lift 94 pounds onto stands, had to hire somebody to do that to my SP2-XT. So separate HF horn has been done by others. The box doesn't have any effect on the HF horn - as I suspected. Messy crossover wiring is a plus, IMHO. The burglar that stole the SP2-XTs 2600 LP's and 100 lb electronics parts left all my point to point wired amp projects.
ES600 appears to be 5 db down at 50 hz. I want 3 db down as the SP2-XT were specified. More sealed volume, I guess.
ES600 appears to be 5 db down at 50 hz. I want 3 db down as the SP2-XT were specified. More sealed volume, I guess.
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Thanks for posting the link, the solidstate v tube REW spectrographs towards the end of the page are most intriguing.
Theft of private (personal) belongings is an annoying thing to get over.
Are you talking about the the later SP2?
I thought the horns of those are mounted inside the cab.
For a long time I was interested in the first SP series, with the Keele inspired CH2 horns (attached).
Are you talking about the the later SP2?
I thought the horns of those are mounted inside the cab.
For a long time I was interested in the first SP series, with the Keele inspired CH2 horns (attached).
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The MLTL speakers that I designed and built a few months ago are 2-ways that cover the audible spectrum.
The green trace is the average left and right in room response, on the listening axis (so about 20 degrees off the speaker axis) @ 1 meter. The purple trace is before the final PEQ was applied to the miniDSP 2x4 HD active crossover.
The Linaeum TLS (true line source) tweeter is crossed over at 480Hz, and driven by the B&K ST-140 amp. The Dayton Audio RS225P-4A woofers are crossed at 440Hz and driven by the Schiit Audio Vidar. My preamp is an Audible Illusions Modulus 2C.
The Linaeum TLS tweeters are from a model called LS2 made in the early 1990's . The two curved leaves (with fiber tape as damping) are driven by a 5.5" high voice coil etched on a rectangular film sheet, at the center. There are two bar magnets, one on either side. It is about 94-95dB sensitivity. I measured the TS data, and they are about 3.5gm Mms.
The woofers are wonderful - these are the same drivers used in the Alta Audio Alec speakers, which are also transmission line speakers; though they have a constricted terminus - it looks like a port. Mine obviously are a more conventional mass loaded transmission line. The woofer is about 1/3rd of the way from the closed end. The bass clarity and "speed" and power is better than any speaker I have ever heard. It is strongly down into the upper 20's and I am surprised by how often there is low bass in recordings I have listened to many times over the years.
These speakers (and the stock Linaeum LT1000) are my pandemic wonders. I bought a pair of LT1000 speakers from a pawn shop in Danbury CT on March 8th, for $400. My son, after hearing how good they sounded, found the pair of Linaeum LS2 speakers, just a couple of towns away; also for $400. We own the only Linaeum TLS tweeters that were available for sale last year, as far as I know. These are very rare, indeed.
Paul Paddock, who designed this driver, has not stopped developing it. I would LOVE to hear the newest version, called the WBLS (wide band line source). The one model speaker they sell is called the MC Audiotech Forty-10. He has been developing it for forty years, and each speaker uses 10 WBLS drivers - as an array they are crossed over at 100Hz! Each Forty-10 speaker has two 18" pro audio woofers in an open baffle enclosure - so there is NO DOUBT that a 2-way speaker can cover the whole audible spectrum.
I think that a modern MLTL design, with a masterpiece driver like the WBLS, would be the last speaker I would need to own.
The green trace is the average left and right in room response, on the listening axis (so about 20 degrees off the speaker axis) @ 1 meter. The purple trace is before the final PEQ was applied to the miniDSP 2x4 HD active crossover.
The Linaeum TLS (true line source) tweeter is crossed over at 480Hz, and driven by the B&K ST-140 amp. The Dayton Audio RS225P-4A woofers are crossed at 440Hz and driven by the Schiit Audio Vidar. My preamp is an Audible Illusions Modulus 2C.
The Linaeum TLS tweeters are from a model called LS2 made in the early 1990's . The two curved leaves (with fiber tape as damping) are driven by a 5.5" high voice coil etched on a rectangular film sheet, at the center. There are two bar magnets, one on either side. It is about 94-95dB sensitivity. I measured the TS data, and they are about 3.5gm Mms.
The woofers are wonderful - these are the same drivers used in the Alta Audio Alec speakers, which are also transmission line speakers; though they have a constricted terminus - it looks like a port. Mine obviously are a more conventional mass loaded transmission line. The woofer is about 1/3rd of the way from the closed end. The bass clarity and "speed" and power is better than any speaker I have ever heard. It is strongly down into the upper 20's and I am surprised by how often there is low bass in recordings I have listened to many times over the years.
These speakers (and the stock Linaeum LT1000) are my pandemic wonders. I bought a pair of LT1000 speakers from a pawn shop in Danbury CT on March 8th, for $400. My son, after hearing how good they sounded, found the pair of Linaeum LS2 speakers, just a couple of towns away; also for $400. We own the only Linaeum TLS tweeters that were available for sale last year, as far as I know. These are very rare, indeed.
Paul Paddock, who designed this driver, has not stopped developing it. I would LOVE to hear the newest version, called the WBLS (wide band line source). The one model speaker they sell is called the MC Audiotech Forty-10. He has been developing it for forty years, and each speaker uses 10 WBLS drivers - as an array they are crossed over at 100Hz! Each Forty-10 speaker has two 18" pro audio woofers in an open baffle enclosure - so there is NO DOUBT that a 2-way speaker can cover the whole audible spectrum.
I think that a modern MLTL design, with a masterpiece driver like the WBLS, would be the last speaker I would need to own.
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So before I do something unwarranted....
To brace these mid cabinets....my thoughts were to run a board the vertical length of the cabinets....maybe three total...one to the back of the woofer...and 2 on the other sides splitting the the space equally.
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ok thanks for the advice....the TL in me says to just divide the cabinet up into different lines...no ones looking to add extra bracing to a TL. I could use the sd of the woofer for a CSA of the brace wall spacing....matrix bracing also is an option...but I was looking for opinions from the board...I'll see if my engineering buddy has access to solid works
No really try to ask to someone using Abakak as they must know if it can. I know Solidworks have a plug in which can perform FEM.
There is a bunch of soft which can perform this kind of sim:
List of finite element software packages - Wikipedia
There is a bunch of soft which can perform this kind of sim:
List of finite element software packages - Wikipedia
ABEC/Akabak is BEM and can give the pressure distribution inside the cabinet but for this type of analysis FEM or FEA is needed, Fusion used to do this for free but not now.
Cabinet bracing is another area where you will find a great of arguing over things studied to death by other disciplines long ago.
Here are some links where analysis is already provided
Speaker Enclosure Bracing Simulations | AVS Forum
Loudspeaker Cabinet Bracing: Finite Element Analysis - Part I | Audioholics
Loudspeaker Cabinet Bracing: A Detailed Look on Do's and Dont's | Audioholics
Cabinet bracing is another area where you will find a great of arguing over things studied to death by other disciplines long ago.
Here are some links where analysis is already provided
Speaker Enclosure Bracing Simulations | AVS Forum
Loudspeaker Cabinet Bracing: Finite Element Analysis - Part I | Audioholics
Loudspeaker Cabinet Bracing: A Detailed Look on Do's and Dont's | Audioholics
Imd = depends on music and volume.
My double 15’s crossed 750hz 24db basically flat below 40hz, tuned to 30hz, you could hear voices warble a bit on the rihanna loveeeee song on the unapologetic album. But that is a tumbler song too, so there is that........
That’s where the 3 way would help, but that is more phase crossover stuff also.
I don’t listen quite that loud though anymore, but the bass massage is invigorating !!!!
I am a big fan of “larger” 2-ways.
My double 15’s crossed 750hz 24db basically flat below 40hz, tuned to 30hz, you could hear voices warble a bit on the rihanna loveeeee song on the unapologetic album. But that is a tumbler song too, so there is that........
That’s where the 3 way would help, but that is more phase crossover stuff also.
I don’t listen quite that loud though anymore, but the bass massage is invigorating !!!!
I am a big fan of “larger” 2-ways.
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A very good point that I always forget to factor...I always have to factor this in...a lot of the people who I admire....don't listen to rap, rnb, edm, stuff with an 808 as the heart of the beat. Drakes - Upset is one of my reference songs for deep bass, has a 808 note around 30hz which is one of the lowest notes I've found amongst rap/rnb.....so approaching things more like a home theater may have been warranted...I am somewhere in the middle, which is perfect for me I think...the 18h+ isn't exactly a home theater subwoofer? Or people may not know what they are talking about as well...but with 4 of them I should be able to move air well enough...I haven't had one person bring up rigidity of the woofer in this thread....so that must be a problem of last generation subs....that would be the thing a more "traditional woofer" might have inconsequence to a higher massed diapragm. Or maybe the lower fs (lower than 29hz apparently)
I always thought bass performance was limited by excursion and nothing else.....
Bill Fitzmaurice approach to bracing leaves little to want for, you guys have not tried this aye?
I always thought bass performance was limited by excursion and nothing else.....
Bill Fitzmaurice approach to bracing leaves little to want for, you guys have not tried this aye?
