Brett that's a pretty strict standard. I don't think I've seen one speaker diy or commercial that can fit that requirement, except maybe Maggies or other electrostats. Do you think combing is a real problem? I always thought it was, but Lynn doesn't seem to bothered with it. This hobby is pretty new to me so I don't really know one way or the other.
Hi dobias,
You can use the second (lower) driver to increase bass and fill in for baffle step loss by driving it via a series connected choke.
If the choke is air-core and slightly lower in value than optimum, you can use a ferrite rod out of an AM radio to adjust its value for the most satisfactory reproduction this combination is capable of.
If you do this, then the comb/phasing problem, which Brett mentions because it becomes apparent in the vertical plane, will then not arise.
Cheers ......... Graham.
You can use the second (lower) driver to increase bass and fill in for baffle step loss by driving it via a series connected choke.
If the choke is air-core and slightly lower in value than optimum, you can use a ferrite rod out of an AM radio to adjust its value for the most satisfactory reproduction this combination is capable of.
If you do this, then the comb/phasing problem, which Brett mentions because it becomes apparent in the vertical plane, will then not arise.
Cheers ......... Graham.
parallel full range speakers
Graham,
I already have a 12" bass only below the 12" full range speaker,
plus an additional 12" bass facing the back. I'm using two 4.2mH air core inductors for the bass units. The front bass sees one coil & the back bass has both coils in series for a lower crossover.
My question was, aside from the reenforcing bass speakers, what advantages or problems would I encounter with two full range speakers (operating full range). They would be in a vertical stack & as close together as possible. Since they're identical units, I didn't think there would be any negative effects, but I'm not certain.
As Brett cautioned,"Once the centre-centre distances are > 0.25 wavelength, cancellation (combfiltering) will occur." I can only say, "Huh?". I admit I'm out of my league with this group's knowledge on the subject.
dobias
Graham,
I already have a 12" bass only below the 12" full range speaker,
plus an additional 12" bass facing the back. I'm using two 4.2mH air core inductors for the bass units. The front bass sees one coil & the back bass has both coils in series for a lower crossover.
My question was, aside from the reenforcing bass speakers, what advantages or problems would I encounter with two full range speakers (operating full range). They would be in a vertical stack & as close together as possible. Since they're identical units, I didn't think there would be any negative effects, but I'm not certain.
As Brett cautioned,"Once the centre-centre distances are > 0.25 wavelength, cancellation (combfiltering) will occur." I can only say, "Huh?". I admit I'm out of my league with this group's knowledge on the subject.
dobias
Post #3113
Hi Dobias,
This is something best understood through personal experience.
Set your FM tuner (if it does not mute) so that you can listen to interstation hiss.
If your front loudspeakers are connected in parallel full-range with a centre distance of say 13", where the wavelength frequency is 1kHz, you are going to hear considerable upper-mid and treble level changes as you move your head up and down about their common axis.
With sine driving, these amplitude peaks and troughs will be in different places at different frequencies as you move up and down (comb effect) and be closer together with increasing frequency.
(Or turn your LS on its side and listen to the effect as you walk past it.)
This is why larger loudspeakers are generally not used for mid frequencies - the output from both sides of the cone destructively interfere as soon as you go off axis, thus the HF/mids fall away quite notably. There can also be a central beaming effect unless countered by other aspects of design.
Cheers .......... Graham.
Hi Dobias,
This is something best understood through personal experience.
Set your FM tuner (if it does not mute) so that you can listen to interstation hiss.
If your front loudspeakers are connected in parallel full-range with a centre distance of say 13", where the wavelength frequency is 1kHz, you are going to hear considerable upper-mid and treble level changes as you move your head up and down about their common axis.
With sine driving, these amplitude peaks and troughs will be in different places at different frequencies as you move up and down (comb effect) and be closer together with increasing frequency.
(Or turn your LS on its side and listen to the effect as you walk past it.)
This is why larger loudspeakers are generally not used for mid frequencies - the output from both sides of the cone destructively interfere as soon as you go off axis, thus the HF/mids fall away quite notably. There can also be a central beaming effect unless countered by other aspects of design.
Cheers .......... Graham.
I have had the Tone Tubby Alnico 12's on test baffles of 24"^2 for a couple days now, and am pleased to report that these drivers are stunningly musical for prerecorded music, completely captivating presentation, and I can vouch for them easily, as midbass drivers. In fact, with some form of treble augmentation, they would sound great pretty much just as they are. Magnetar reports great success with the rather inexpensive B&C DE-10 compression driver, and Eminence APT waveguide.
I am sorely tempted to cut dust caps and make for phase plugs, but, the Tubbys, STAY!
I am sorely tempted to cut dust caps and make for phase plugs, but, the Tubbys, STAY!
Hi Doc,
How do the Tubbys compare to the Coral 12" drivers?
My most recent OB configuration uses the Fostex FE208Sigmas (got them for free from Nelson Pass at the "Burning Amp" event, thanks Nelson!), and has two 15" woofers (with active EQ and horizontally aligned) on each OB. This combination does a much better imitation of real concert sound than my other OB projects using smaller FR drivers. I just participated in two performances of Carmina Burana last week, with ~ 240 singers on the stage and a full orchestra. When I played the Ozawa 1965 recording of this music through the OB speakers, I was quite happy to discover that the OB speakers actually were able to give a decent hint of the real sound, including the weight of human voices and the impact of the bass and percussion.
Cheers,
Kurt
How do the Tubbys compare to the Coral 12" drivers?
My most recent OB configuration uses the Fostex FE208Sigmas (got them for free from Nelson Pass at the "Burning Amp" event, thanks Nelson!), and has two 15" woofers (with active EQ and horizontally aligned) on each OB. This combination does a much better imitation of real concert sound than my other OB projects using smaller FR drivers. I just participated in two performances of Carmina Burana last week, with ~ 240 singers on the stage and a full orchestra. When I played the Ozawa 1965 recording of this music through the OB speakers, I was quite happy to discover that the OB speakers actually were able to give a decent hint of the real sound, including the weight of human voices and the impact of the bass and percussion.
Cheers,
Kurt
Magnetar: I appreciate the condolences! Sucks but in the end I got drivers that rock so it's all good. 
The Seleniums sound great to me! Adding them has taken the system to whole other place. I'm feeling quite privileged, the entire system sounds astonishingly good. I don't think many people ever get to hear recorded music presented at this level. Thanks for blazing a trail I could follow, for sure I owe you some beers.
Lynn: Thanks for the lengthy reply! I do realize time alignment and rapid decay are two different things, just one got me thinking about the other. Two thinks I suspected are, I believe, confirmed. 1) We have almost no idea how important time alignment is. 2) Any attempt at absolute time align is compromised at best.
The link to your site provided lots of interesting reading. I especially enjoyed the short history of hi-fi. Interesting how audio consumers have been lead around by the nose going exactly where the big money players want us. I've been in the same position you mention auditioning a SS amp with a group and being the only one who thought it was horrid! That was years ago and it was kind of lonely. I realized much later that a pair of La Scalas and a Crown DC-300A drove me away from listening to recorded music for several years.
During the same time period there was a serious push to sell SS to guitarists. Thankfully I have no memory of a group of players raving over the latest SS turd.
The Seleniums sound great to me! Adding them has taken the system to whole other place. I'm feeling quite privileged, the entire system sounds astonishingly good. I don't think many people ever get to hear recorded music presented at this level. Thanks for blazing a trail I could follow, for sure I owe you some beers. Lynn: Thanks for the lengthy reply! I do realize time alignment and rapid decay are two different things, just one got me thinking about the other. Two thinks I suspected are, I believe, confirmed. 1) We have almost no idea how important time alignment is. 2) Any attempt at absolute time align is compromised at best.
The link to your site provided lots of interesting reading. I especially enjoyed the short history of hi-fi. Interesting how audio consumers have been lead around by the nose going exactly where the big money players want us. I've been in the same position you mention auditioning a SS amp with a group and being the only one who thought it was horrid! That was years ago and it was kind of lonely. I realized much later that a pair of La Scalas and a Crown DC-300A drove me away from listening to recorded music for several years.
During the same time period there was a serious push to sell SS to guitarists. Thankfully I have no memory of a group of players raving over the latest SS turd. hi Kurt,
The Tubbys are pretty much in a league of their own. The hemp vibe is just magnified it seems, by the addition of the Alnico magnet, whose properties pretty much defy a written explanation, other than Lynns' description, of "low level delicacy," which addresses it nicely. They are stunningly musical. Giant Lowthers with balls. A 2 wat SET provides scary dynamic capability.
Are you using the Dayton 15-IB woofers?
The Tubbys are pretty much in a league of their own. The hemp vibe is just magnified it seems, by the addition of the Alnico magnet, whose properties pretty much defy a written explanation, other than Lynns' description, of "low level delicacy," which addresses it nicely. They are stunningly musical. Giant Lowthers with balls. A 2 wat SET provides scary dynamic capability.
Are you using the Dayton 15-IB woofers?
Hello,
I am sorry for the slight off-topic. I have a question I am sure have adressed here but I don't find it with the search function:
What is the program Bjorno uses in the simulations above?
Thank you!
dmason,
it's great you can offer a feedback on the tubby's. The selenium woofers seem to be a safe bet too.
I am sorry for the slight off-topic. I have a question I am sure have adressed here but I don't find it with the search function:
What is the program Bjorno uses in the simulations above?
Thank you!
dmason,
it's great you can offer a feedback on the tubby's. The selenium woofers seem to be a safe bet too.
Hi Dan,
Glad to hear that you like the Tubbys that much.
I am acutally going to San Diego around the end of this month. Perhaps I can stop by to say hello? I'll PM you.
I am not using the Dayton 15" IB woofers. Just some clearance-sale 15" subwoofer drivers I got from PartsExpresss several years ago. I've set a policy for myself to try to use the drivers I already have (too many already) before buying new ones. Someday when I have finally settled on an "ultimate" OB design, I'll consider buying better drivers to build that design. Let's see if the Tubbys will become part of that design.
Cheers,
Kurt
Glad to hear that you like the Tubbys that much.
I am acutally going to San Diego around the end of this month. Perhaps I can stop by to say hello? I'll PM you.
I am not using the Dayton 15" IB woofers. Just some clearance-sale 15" subwoofer drivers I got from PartsExpresss several years ago. I've set a policy for myself to try to use the drivers I already have (too many already) before buying new ones. Someday when I have finally settled on an "ultimate" OB design, I'll consider buying better drivers to build that design. Let's see if the Tubbys will become part of that design.
Cheers,
Kurt
Hi SunRa,
See page 30 posting #47:
http://www.diyaudio.com/forums/showthread.php?threadid=100392&perpage=25&pagenumber=30
b
See page 30 posting #47:
http://www.diyaudio.com/forums/showthread.php?threadid=100392&perpage=25&pagenumber=30
b
Just to draw attention to the previous posts - the simplest version of what I've blathering about for almost a year would be:
Some kind of compression-driver HF - at the minimum, a B&C DE25 with one of the waveguides that Magnetar and others have suggested, the 18Sound XD125, or any of several other 1" plastic-film compression drivers.
Midbass - the 12" Tone Tubby, with or without EQ, to personal taste. In terms of EQ, there's a lot less to EQ than a Lowther or Fostex (which both have much rougher response), far higher power-handling, no midrange "shout" thanks to no whizzer cone, and just as much delicacy thanks to an old-school paper VC former and an Alnico magnet. Listen to the TT, you won't go back to drivers with whizzers - and I'm including the Feastrex here.
Bass-fill - Good to hear the 15" Seleniums are working out. They certainly have more appealing specs than many guitar speakers - more Xmax, quite usable Qts, and higher efficiency as well. I'd use two of them side-by-side at floor level, with the TT directly above them.
The higher power handling, efficiency and cone area of the Seleniums are very desirable in an OB system. The problem with the great majority of OB's is simply not enough power-handling for the task, which is what I heard at the RMAF. If you economize on cone area and efficiency, you get thin and scrawny sound. Get the dynamics right, and the other virtues of OB can shine out.
Crossover - there's no reason the HF and midbass can't use a straightforward passive crossover in the 1.5~2.5 kHz region. The bass-fill drivers can be independently driven with a 100~200W prosound transistor amplifier, with a prosound crossover/parametric equalizer. Note if you use a digital crossover/EQ, there will be a latency delay between input and output, depending on the amount of signal processing you do.
I would strongly urge that you do NOT pass the mid and HF signal through the pretty marginal sounding electronics of the crossover/EQ unit, and use high-quality amplification for the mid and HF units.
I consider Class AB, D, and T amplifiers on the lower bound of hifi, since all of them have significant rises in distortion with increasing frequency - fine for bass, not so fine for the highest quality mid/high applications. By avoiding switching artifacts (inherent in Class AB, B, D, and T) in the forward signal path, true (thermal) Class A amplification has better performance at lower levels and higher frequencies.
I like direct-heated triodes for the way they sound and their extremely low inherent distortion, but other folks like solid-state Class A - which require astonishingly large heat-sinks if the amplifier is true thermal Class A. Dynamic sliding-bias Class AB isn't really the same as true Class A (despite marketing claims to the contrary), but it does sound (a little) better than plain old-fashioned thermal-tracking Class AB.
Some kind of compression-driver HF - at the minimum, a B&C DE25 with one of the waveguides that Magnetar and others have suggested, the 18Sound XD125, or any of several other 1" plastic-film compression drivers.
Midbass - the 12" Tone Tubby, with or without EQ, to personal taste. In terms of EQ, there's a lot less to EQ than a Lowther or Fostex (which both have much rougher response), far higher power-handling, no midrange "shout" thanks to no whizzer cone, and just as much delicacy thanks to an old-school paper VC former and an Alnico magnet. Listen to the TT, you won't go back to drivers with whizzers - and I'm including the Feastrex here.
Bass-fill - Good to hear the 15" Seleniums are working out. They certainly have more appealing specs than many guitar speakers - more Xmax, quite usable Qts, and higher efficiency as well. I'd use two of them side-by-side at floor level, with the TT directly above them.
The higher power handling, efficiency and cone area of the Seleniums are very desirable in an OB system. The problem with the great majority of OB's is simply not enough power-handling for the task, which is what I heard at the RMAF. If you economize on cone area and efficiency, you get thin and scrawny sound. Get the dynamics right, and the other virtues of OB can shine out.
Crossover - there's no reason the HF and midbass can't use a straightforward passive crossover in the 1.5~2.5 kHz region. The bass-fill drivers can be independently driven with a 100~200W prosound transistor amplifier, with a prosound crossover/parametric equalizer. Note if you use a digital crossover/EQ, there will be a latency delay between input and output, depending on the amount of signal processing you do.
I would strongly urge that you do NOT pass the mid and HF signal through the pretty marginal sounding electronics of the crossover/EQ unit, and use high-quality amplification for the mid and HF units.
I consider Class AB, D, and T amplifiers on the lower bound of hifi, since all of them have significant rises in distortion with increasing frequency - fine for bass, not so fine for the highest quality mid/high applications. By avoiding switching artifacts (inherent in Class AB, B, D, and T) in the forward signal path, true (thermal) Class A amplification has better performance at lower levels and higher frequencies.
I like direct-heated triodes for the way they sound and their extremely low inherent distortion, but other folks like solid-state Class A - which require astonishingly large heat-sinks if the amplifier is true thermal Class A. Dynamic sliding-bias Class AB isn't really the same as true Class A (despite marketing claims to the contrary), but it does sound (a little) better than plain old-fashioned thermal-tracking Class AB.
Hello,
I was thinking at the importance of the 300-1Khz spectrum of music and I was wondering if two Tone Tubby's per side would have combing/difraction problems.
Why using two? There are a couple of good reasons: around 100dB SPL in this configuration, and so easyer to match with a phenolic or radian CD in a 30cm waveguide, easier support of the highly complex music in this frequency region (a problem especially in open baffle where Sd really counts).
So again, what problems could appear in this configuration, considering a low-pass around 900-1.2Khz?
edit: 2 Lil' Buddys per side would also qualify with the advantage of a smaller offset between their sound centers and with even higher spl. Although the bottom end might not be as good as for the tubby's, nor the sweet alnico sound.
I was thinking at the importance of the 300-1Khz spectrum of music and I was wondering if two Tone Tubby's per side would have combing/difraction problems.
Why using two? There are a couple of good reasons: around 100dB SPL in this configuration, and so easyer to match with a phenolic or radian CD in a 30cm waveguide, easier support of the highly complex music in this frequency region (a problem especially in open baffle where Sd really counts).
So again, what problems could appear in this configuration, considering a low-pass around 900-1.2Khz?
edit: 2 Lil' Buddys per side would also qualify with the advantage of a smaller offset between their sound centers and with even higher spl. Although the bottom end might not be as good as for the tubby's, nor the sweet alnico sound.
Lynn
You just answered a bunch of my questions. I've got the fever after reading about magnetar's latest success. I am considering the Lil Buddy 10" and B&C DE10 because the Tone Tubs are out of my budget. Was also looking at the 15" Seleniums and wondering if 4 are necessary. So now I guss they are. I was going to use an old behringer xo to separate the subs from the mids and understand what you mean about usin the low output only. So are you saying to just put a cap bundle in series with the mid array? If so, how good do they have to be? Will a couple of electrolytics with a quality bypass cap do the trick? And what xo frequency should I aim for?
Thanks, Jon
You just answered a bunch of my questions. I've got the fever after reading about magnetar's latest success. I am considering the Lil Buddy 10" and B&C DE10 because the Tone Tubs are out of my budget. Was also looking at the 15" Seleniums and wondering if 4 are necessary. So now I guss they are. I was going to use an old behringer xo to separate the subs from the mids and understand what you mean about usin the low output only. So are you saying to just put a cap bundle in series with the mid array? If so, how good do they have to be? Will a couple of electrolytics with a quality bypass cap do the trick? And what xo frequency should I aim for?
Thanks, Jon
Jon,
I’m not Lynn but I can also give you my point of view on hi pass caps or any cap on a passive XO…
They are as critical as any other cap on the system and I would never consider lytics, caps should be non polar, my preference goes for good Poyprop and they should be adequate bypass by a combination of smaller caps down to 0.1uf. bypass caps should be the best you can afford. Test for best results.
Amp performance is directly related to its load so the combination of XO + speakers is of prime importance.
My two cents.
I’m not Lynn but I can also give you my point of view on hi pass caps or any cap on a passive XO…
They are as critical as any other cap on the system and I would never consider lytics, caps should be non polar, my preference goes for good Poyprop and they should be adequate bypass by a combination of smaller caps down to 0.1uf. bypass caps should be the best you can afford. Test for best results.
Amp performance is directly related to its load so the combination of XO + speakers is of prime importance.
My two cents.
Two 10" to 12" LS side by side are going to lead to notable voice reproduction anomalies for any listening done off-axis, especially with a combining reflected rear wave.
Its not just the centre to centre spacing, but the overall spacing between outer cone edges which will promote frequency selective interferences.
Cheers ........... Graham.
Its not just the centre to centre spacing, but the overall spacing between outer cone edges which will promote frequency selective interferences.
Cheers ........... Graham.