IMO the WO24 paper version has a rather flexible cone and sounds a little soft in the midbass. The textreme version is night and day better if you care about transient response. The bigger Seas drivers are also excellent. The U22REX-P is one of my favorite extended range 8" woofers. It can cross at 2k + with little work.
Thanks Profiguy!
How is the tone when crossed on 500hz with textreme version?
I Have tw29txn tweeter and it is smooth sounding so im not extremely worried, but still thought to ask..
How is the tone when crossed on 500hz with textreme version?
I Have tw29txn tweeter and it is smooth sounding so im not extremely worried, but still thought to ask..
Thr best simple description for the WO24TX is accurate, but a bit laid back.
It would probably be my first choice for a medium sensitivity woofer for a 3 way.
It would probably be my first choice for a medium sensitivity woofer for a 3 way.
These high sensitivity 3" beat every 6,5" out there. There are a few PA midrange which can produce the same SPL but non of them get the resolution and details of the 3" domes. Which leads to a "naturalness" of the midrange when implemented right.
I prefer to keep off axis sound linear and do some EQ correction when you need a "softer" sound - which is done in PA very often. 1-4kHz is a little lower as I prefer, center frequency around 2,5-3kHz. 2dB already change a lot.
Had been hesitant to mate such a wide tweeter to the D7608, but I think I'll just go for it. Think I'll use the SB26STCN because I already have a pair, and profiguy has told me in dms the distortion profile matches up pretty well.
Shooting for a crossover point of 3KHz, I wonder if I should space the drivers according to the Kimmosto rule? (1.2 wavelength for CTC)
This would give me a 1" gap between the edges of D7608 and SB26STCN, so I wouldn't be taking advantage of the latter's small size
Shooting for a crossover point of 3KHz, I wonder if I should space the drivers according to the Kimmosto rule? (1.2 wavelength for CTC)
This would give me a 1" gap between the edges of D7608 and SB26STCN, so I wouldn't be taking advantage of the latter's small size
I'd go with 1.2 x WL spacing. Thats a good happy medium and provides the most functional lobing compared with other spacing strategies.
2 strategies.
Getting drivers as close as possible and crossover as low as possible - that's what I do.
Or choosing a higher crossover and going 1.2 x WL. This works very well in a typical listening distance and typical room height.
That's probably a good approach. In this particular instance I am interested in using most of the bandwidth the D7608 has to offer, and 3KHz looks like a good starting point just looking at graphs. Also, I've read the tweeter I'm using sb26stcn starts to complain below 3k, I think from profiguy. I'm still very much a newbie to this stuff, but intuitively it makes sense to me to give as much of the midrange as you can to one driver. I think I'd use your go to method though if I ever do a 2 way with a super robust tweeter. Got some Peerless CD's I will probably implement in that fashion
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I haven't mentioned something rather important in my previous post concerning the mid dip crossover strategy.
Using offset filters will adjust phase relationship to some degree, but when the phase is offset evenly at both ends of the stop band (with ie. 2nd order network) through a specific percentage larger value series coil on the mid and smaller tweeter cap, the phase will track correctly (given that it's been verified in simulations and modeling). The resulting filter slope shapes will be somewhat "elliptical" shape, providing the correct phase relationship and sum/track predictably.
You can of course use LCRs to do the job just as well, but it requires more crossover components. I prefer to use a multi position switch with different resistor values to choose the mid attenuation level amount. For example, a series LCR of roughly 0.35 - 0.4 mH, 3.3 - 3.9 uF and 2/4/8 ohm 10 - 15W attenuation resistors (placed parallel right at each driver) will get you close to the target center frequency. You'll of course need one LCR per mid and tweeter, plus I recommend modeling the LCR to suit average driver impedance, as the driver itself may need its own exact LCR component values. The ones I mentioned will get you close though and they don't need to be of highest caliber grade being connected in parallel with the drivers. Polyester caps, thin gauge (18+ awg) air core coils and standard wire wound resistors are totally acceptable. That's given you account for built in coil DCR when choosing resistor values.
Using offset filters will adjust phase relationship to some degree, but when the phase is offset evenly at both ends of the stop band (with ie. 2nd order network) through a specific percentage larger value series coil on the mid and smaller tweeter cap, the phase will track correctly (given that it's been verified in simulations and modeling). The resulting filter slope shapes will be somewhat "elliptical" shape, providing the correct phase relationship and sum/track predictably.
You can of course use LCRs to do the job just as well, but it requires more crossover components. I prefer to use a multi position switch with different resistor values to choose the mid attenuation level amount. For example, a series LCR of roughly 0.35 - 0.4 mH, 3.3 - 3.9 uF and 2/4/8 ohm 10 - 15W attenuation resistors (placed parallel right at each driver) will get you close to the target center frequency. You'll of course need one LCR per mid and tweeter, plus I recommend modeling the LCR to suit average driver impedance, as the driver itself may need its own exact LCR component values. The ones I mentioned will get you close though and they don't need to be of highest caliber grade being connected in parallel with the drivers. Polyester caps, thin gauge (18+ awg) air core coils and standard wire wound resistors are totally acceptable. That's given you account for built in coil DCR when choosing resistor values.
I'd cross at 3k as well. A little higher if you want better HF (mechanical) power handling. It will allow for a lower order filter (I prefer 2nd order). You can of course go even lower and steeper, but then you're throwing away mid response and maybe gaining more linear directivity.
@Bryguy The issue with going as close CTC possible can be ending up with unfavorable vertical lobing. I'd verify a given CTC before committing. It can significantly negatively affect the speaker's performance, depending on how much value is placed on the vertical listening window.
Ill make a test baffle first. I have a software on my computer which basically simulates vertical lobe, with inputs for crossover frequency and CTC. I don't know how well it translates to real world applications, or if it has a z axis input. I'll find the name of the software next time I'm at my computer
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And I do the opposite from profiguy - I would NEVER cross the T34A at 3K 😎
This tweeter is a beast, no need to cross extra high and get directivity from your mid dome. Until you WANT uneven directivity and less acoustical power in that frequency range in your room.
It's always hard to predict what a driver can deliver at high SPL levels, you need to do proper measurements. Also the baffle influences the transition and needed filter. But I'm often surprised how low you can cross these modern tweeters without any THD penalty.
For extreme SPL a 1" would be needed to cross at 3k (music content goes down above that frequency) but T34A can put out at least 6dB more.
@IamJF We definitely disagree on the T34A/B HP. A.good number of speaker designers would side with you on this one, but I won't. In an elaborate way of putting things, here's why....
My big beef with lower tweeter HP points is I can hear the tweeter do things I don't like even though the HD measurements on paper. The T34B doesn't sound good to me under 3k... at least my own personal ones don't. Same is true with many other larger domes. Just because they're large domes doesn't make them capable of playing lower/louder without some form of audible issues, even if the HD data says to the contrary. There are many possible reasons for this, not just related to a large diaphragm.
A big issue with large domes is they tend to do non linear things which can't be easily observed with the common driver testing methods and devices. Laser interferrometry can detect this, but its not a very accessible test method to most designers. Simply put, I don't like a single suspension driver moving alot. Thats why I prefer the most emissive surface area possible with the least diaphragm movement. "Low enough" HD isn't "good enough" to me, which is still noticeable with specific musical content. This is unlike tone/pink/white noise bursts or static test signals which don't exactly/fully represent all of the possible negative performance traits and behavior from a driver. There are some things we can't detect with typical measurment gear and methodology.
Next issue for me is crossing a driver in a sensitive region, denying its full bandwidth potential with flatter phase trend, specifically having a single driver delivering the entire sensitive range uninterrupted. This is a huge benefit on a 3 way, likely the biggest benefit of all. Sticking a crossover point in there, especially with a steep filter that throws the phase around is exceptionally destructive to imaging, phantom center and soundstage. Percussive transients will suffer as well,.depending on how accurate they're preserved in the recording.
Directivity isn't everything in the real world to me and its not as critical as one would think - certainly not worth negating all the benefits I listed above. People make such a huge deal about this, it becomes an obsession. You can still have good (non-optimal) off axis performance using the tricks I suggest and reap the rewards of a more time domain accurate speaker without the need for DSP or hammer fisted, sharp filter cutoffs. Yes, you can have phase correct filters this way, but there's no free lunch ie. pre-ringing and artifacts related to processing errors.
The way a speaker performs playing back music is significantly different than reproducing test signals. Specifically transient IMD isn't well represented with just a few test frequencies. The full audio spectrum from music is a far more accurate indicator of IMD in every way. Yes, chances are, if there are problems in the usual test signal domain, there will be even more issues with complex music containing countless harmonic structures and their relationships.
Bottom line is, the SOLE purpose of a 3 way speaker IMO is so the critical midrange from circa 500 hz - 4k can come from ONE single driver. If you split that range, you may as well build a 2 way. Even if you don't have perfect off axis performance with a tighter sweet spot, you can still treat the room properly so it doesn't disrupt soundstage, imaging and phantom center, even with a relatively (on paper) less than ideal power response.
As I said before, unless I'm building a flat sounding monitor or PA speaker (which I'm not), I'm always going to put my priorities first before perfect off axis coverage in multiple, acoustically compromised listening environments. This compromise would involve hacking up other areas of performance which are IMO far more important to enjoyable, non fatiguing, yet convincingly accurate sounding music reproduction for the majority of scenarios and listeners tastes. Yes, I'm mainly approaching this from a psychoacoustic perspective. And I'm not going to quote GL metrics, etc... sorry. Its a bit more complicated that that.
Alot of this obsessive off axis perfection trend is spilling over into PA design. I believe its a big part of why most live concerts sound like **** these days despite all of the so called "advances" in sound reinforcement we've supposedly made. These advances are shifts in priorities that have pushed the most important aspects of SQ aside when it comes to the execution of most modern PAs. Its supposed to be important to provide even, intelligible coverage across the venue, but its come at a huge cost and consequence to the integrity of the actual SQ. Its far from actually delivering transient correct, truly low distortion sound that doesn't make peoples ears bleed. Then there's the LF... thats a whole different mess thats just pathetic. I'm a bassist, and when I go to a concert, I want to be able to discern the individual notes, not have my bowels oblitered with a muddled LF cacophony....
Anyways, there's way more to accurate sound reproduction than mainly even coverage, and certainly not at the cost of increased harshness, fatigue and odd types of distortion which don't exist in even the most primitive 2 way speakers. Combing, smearing and transient distortion from highly diffracting WGs is apparently more acceptable...
I design and build speakers for the purpose of enjoying most types of music, delivering the most convincing accuracy possible while having the lowest possible amount of relative distortion, fatigue and stress to hearing. That doesn't mean putting a smily face EQ on everything and calling it good. Its much more complex than that. There is no cookie cutter formula for this. Specific parameters are more important than others to make this work successfully and convincingly. This is why I look at designing speakers from a wide perspective, not just from gospel coming from engineers wanting to hear themselves talk about how they figured out some special formula that explains it all black and white. Sorry, that simply doesn't exist. Sure, I have my own prejudices and methods of subjective approach, but I try to focus on the most important stuff first. So, is off axis response really that holy grail of speaker design?
Sorry, I had to take the ball and run with this one. I just don't agree and thats why I'm trying to present other options to people who want accurate sound that doesn't offend in other ways. Speakers are like chairs for people... there's one for every @$$.
My big beef with lower tweeter HP points is I can hear the tweeter do things I don't like even though the HD measurements on paper. The T34B doesn't sound good to me under 3k... at least my own personal ones don't. Same is true with many other larger domes. Just because they're large domes doesn't make them capable of playing lower/louder without some form of audible issues, even if the HD data says to the contrary. There are many possible reasons for this, not just related to a large diaphragm.
A big issue with large domes is they tend to do non linear things which can't be easily observed with the common driver testing methods and devices. Laser interferrometry can detect this, but its not a very accessible test method to most designers. Simply put, I don't like a single suspension driver moving alot. Thats why I prefer the most emissive surface area possible with the least diaphragm movement. "Low enough" HD isn't "good enough" to me, which is still noticeable with specific musical content. This is unlike tone/pink/white noise bursts or static test signals which don't exactly/fully represent all of the possible negative performance traits and behavior from a driver. There are some things we can't detect with typical measurment gear and methodology.
Next issue for me is crossing a driver in a sensitive region, denying its full bandwidth potential with flatter phase trend, specifically having a single driver delivering the entire sensitive range uninterrupted. This is a huge benefit on a 3 way, likely the biggest benefit of all. Sticking a crossover point in there, especially with a steep filter that throws the phase around is exceptionally destructive to imaging, phantom center and soundstage. Percussive transients will suffer as well,.depending on how accurate they're preserved in the recording.
Directivity isn't everything in the real world to me and its not as critical as one would think - certainly not worth negating all the benefits I listed above. People make such a huge deal about this, it becomes an obsession. You can still have good (non-optimal) off axis performance using the tricks I suggest and reap the rewards of a more time domain accurate speaker without the need for DSP or hammer fisted, sharp filter cutoffs. Yes, you can have phase correct filters this way, but there's no free lunch ie. pre-ringing and artifacts related to processing errors.
The way a speaker performs playing back music is significantly different than reproducing test signals. Specifically transient IMD isn't well represented with just a few test frequencies. The full audio spectrum from music is a far more accurate indicator of IMD in every way. Yes, chances are, if there are problems in the usual test signal domain, there will be even more issues with complex music containing countless harmonic structures and their relationships.
Bottom line is, the SOLE purpose of a 3 way speaker IMO is so the critical midrange from circa 500 hz - 4k can come from ONE single driver. If you split that range, you may as well build a 2 way. Even if you don't have perfect off axis performance with a tighter sweet spot, you can still treat the room properly so it doesn't disrupt soundstage, imaging and phantom center, even with a relatively (on paper) less than ideal power response.
As I said before, unless I'm building a flat sounding monitor or PA speaker (which I'm not), I'm always going to put my priorities first before perfect off axis coverage in multiple, acoustically compromised listening environments. This compromise would involve hacking up other areas of performance which are IMO far more important to enjoyable, non fatiguing, yet convincingly accurate sounding music reproduction for the majority of scenarios and listeners tastes. Yes, I'm mainly approaching this from a psychoacoustic perspective. And I'm not going to quote GL metrics, etc... sorry. Its a bit more complicated that that.
Alot of this obsessive off axis perfection trend is spilling over into PA design. I believe its a big part of why most live concerts sound like **** these days despite all of the so called "advances" in sound reinforcement we've supposedly made. These advances are shifts in priorities that have pushed the most important aspects of SQ aside when it comes to the execution of most modern PAs. Its supposed to be important to provide even, intelligible coverage across the venue, but its come at a huge cost and consequence to the integrity of the actual SQ. Its far from actually delivering transient correct, truly low distortion sound that doesn't make peoples ears bleed. Then there's the LF... thats a whole different mess thats just pathetic. I'm a bassist, and when I go to a concert, I want to be able to discern the individual notes, not have my bowels oblitered with a muddled LF cacophony....
Anyways, there's way more to accurate sound reproduction than mainly even coverage, and certainly not at the cost of increased harshness, fatigue and odd types of distortion which don't exist in even the most primitive 2 way speakers. Combing, smearing and transient distortion from highly diffracting WGs is apparently more acceptable...
I design and build speakers for the purpose of enjoying most types of music, delivering the most convincing accuracy possible while having the lowest possible amount of relative distortion, fatigue and stress to hearing. That doesn't mean putting a smily face EQ on everything and calling it good. Its much more complex than that. There is no cookie cutter formula for this. Specific parameters are more important than others to make this work successfully and convincingly. This is why I look at designing speakers from a wide perspective, not just from gospel coming from engineers wanting to hear themselves talk about how they figured out some special formula that explains it all black and white. Sorry, that simply doesn't exist. Sure, I have my own prejudices and methods of subjective approach, but I try to focus on the most important stuff first. So, is off axis response really that holy grail of speaker design?
Sorry, I had to take the ball and run with this one. I just don't agree and thats why I'm trying to present other options to people who want accurate sound that doesn't offend in other ways. Speakers are like chairs for people... there's one for every @$$.
Alot of speakers that have perfect power response still sound bad and need alot of EQ correction to sound non-hostile to most ears (unless you're a deaf drummer).
A good test is cranking up the volume, when playing back a decent big band jazz orchestra recording. Chances are that perfect power response speaker is going to suddenly be hurting alot of people.
Good speakers properly designed for a specific listening environment will sound good at almost any volume level (within the max output capabilities of the drivers as a whole).
There's no such thing as a speaker that sounds good as is in every environment, despite posessimg theoretically perfect power response.
A good test is cranking up the volume, when playing back a decent big band jazz orchestra recording. Chances are that perfect power response speaker is going to suddenly be hurting alot of people.
Good speakers properly designed for a specific listening environment will sound good at almost any volume level (within the max output capabilities of the drivers as a whole).
There's no such thing as a speaker that sounds good as is in every environment, despite posessimg theoretically perfect power response.