Member
Joined 2009
Im confused on your point. A 3-way design is not extremely detailed and lacks imaging?? I always thought my 3-way design (Neopro5i, PHL1120, TD12S) was extremely detailed. More so then any paradigm or B&W speaker I have owned.
Let's assume a 2-way with an 8" woofer and a dome mid. This is SPEAKER1. The woofer will have wide dispersion in the lower frequencies, then it will narrow in the midrange. At the crossover frequency the tweeter will have a very wide dispersion that will narrow towards the high frequencies. The dip/peak at the midrange and crossover will cause problems so for the sake of simplicity let's say this 2-way won't sound great in a typical living room. It will sound pretty good but not great.
Let's add a 4" midrange driver and make this a 3-way and call it SPEAKER2. With the mid the wide dispersion will stay through midrange and only start to narrow at the frequencies covered by the tweeter. The 3-way SPEAKER2 will sound better than the 2-way SPEAKER1.
Now, let's consider a SPEAKER3 which is a 2-way with an 8" woofer and a waveguide on the tweeter. SPEAKER3 is designed with Constant Directivity in mind so the dispersion is wide at the lows, narrow at the mids and all the way through the highs. Typical implementations are Mark K's ER18DXT and the Behringer B2030 monitors. SPEAKER3 will interact with room less in the mids where the ear is most sensitive.
Under typical conditions and all other parameters similar, SPEAKER3 > SPEAKER2 > SPEAKER1. Because the drivers in SPEAKER2 operate in their optimal range however, generally the system as a whole would have the best resolution. Also with the appropriate understanding SPEAKER2 and the room can be optimized to have the same favorable quality associated with the Constant Directivity of SPEAKER3. SPEAKER3 is more versatile and flexible with positioning.
That makes sense to me now.
I thought the only major advantage with a waveguide is less beaming at higher FQ.
But you say it also interacts with the room less, so less reflections.
Got ya.
My design will stay as a 2-way, Selenium D220ti and Delta 12LFA.
They are now in a sealed enclosure (70L, QTC=0.8) to save space and I can apply some Linkwitz transform EQ with the MiniDSP.
Next question, glue or screws?
I thought the only major advantage with a waveguide is less beaming at higher FQ.
But you say it also interacts with the room less, so less reflections.
Got ya.
My design will stay as a 2-way, Selenium D220ti and Delta 12LFA.
They are now in a sealed enclosure (70L, QTC=0.8) to save space and I can apply some Linkwitz transform EQ with the MiniDSP.
Next question, glue or screws?
Member
Joined 2009
Gainphile: S15 - Econowave DSP
This build sounds much like what you are after. I think there is a thread about it here on diyaudio as well.
Reflections are not necessarily bad but it's critical that the sound projected towards a reflective boundary has a flat frequency response. Another critical item is the time it takes for the sound to travel from the source to the reflecting object. I'm not too clear on that part but the general guideline of >2' from the sidewalls and >3' from the backwall works for me.
This build sounds much like what you are after. I think there is a thread about it here on diyaudio as well.
Reflections are not necessarily bad but it's critical that the sound projected towards a reflective boundary has a flat frequency response. Another critical item is the time it takes for the sound to travel from the source to the reflecting object. I'm not too clear on that part but the general guideline of >2' from the sidewalls and >3' from the backwall works for me.
Yes I am familiar with that incarnation of the Econowave, the S15 is what inspired me to build me own.
I did start out with a 120L ported enclosure but it was way to wide and ugly (wife would not approve), or to tall (unstable around the kids). So I settled on a smaller 70L sealed enclosure.
I read that 29 page document that "Brett" posted up and it was quite digestible and made sense. Thanks.
I must admit the MiniDSP makes it much easier to play around with cross over’s and different types of speaker design, I started with MJK open baffle speaker and have since taken it apart as it was to big and to ugly and impractical, but I had a lot of fun building and listening to them.
I am looking forward to getting these Econowave speakers finished.
I did start out with a 120L ported enclosure but it was way to wide and ugly (wife would not approve), or to tall (unstable around the kids). So I settled on a smaller 70L sealed enclosure.
I read that 29 page document that "Brett" posted up and it was quite digestible and made sense. Thanks.
I must admit the MiniDSP makes it much easier to play around with cross over’s and different types of speaker design, I started with MJK open baffle speaker and have since taken it apart as it was to big and to ugly and impractical, but I had a lot of fun building and listening to them.
I am looking forward to getting these Econowave speakers finished.
They are now in a sealed enclosure (70L, QTC=0.8) to save space and I can apply some Linkwitz transform EQ with the MiniDSP.
Next question, glue or screws?
If you have clamps then just screws. If you do not have enough clamps then screws are just fine
btw, how does the Eminence woofer measure with 70L and LT EQing??? I have some builds down the road with the deltalite/DE250/QSC HPR152i and I would love to have a 70L box.
Besides sound pressure there is no reason to use a 12" in a two way so what so what level are you thinking off at 1 Watt. And witch cutoff frequency. Or what maximum spl do you need.
Other wise you can consider 10" or to increase sound pressure 3dB more 2X10" is a option. For a two way design.
Here a 70liter 2way 30Hz-17kHz 92dB 1Wmtr -3dB ,25Hz-20kHz -10dB. Passive filter.http://www.diyaudio.com/forums/multi-way/193513-project-monitor-xl-reference-values.html
It is a t the limit what you can do of bandwith and lowcutoff frequency and soundpressure at that size.
And detail is made in the midrange 200-10000Hz I searched it in the past HF with super tweeters, that was wrong micro-detail is made in the midrange we are very sensitive to. There you need the highest quality. BG makes dipoles in that range Stigerik use them he is very satisfied and has much experience in building loudspeakers. To do better then those BG will be hard I gues.
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So a three way would be better to choose a good driver from 200Hz up. 18sound has a very good 6" 93dB 1wmtr.
That one with a 12" and a small horn like the ME10 would be nice to create average sound pressure of 94-95dB 1Wmtr. With a 12" woofer I guess passive this means 50Hz cutoff in 70liter BR-enclosure.
To minimize horn coloration I choose a smaller horn like the ME10 and let the 6" go up to 3khz.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=294-618
That one with a 12" and a small horn like the ME10 would be nice to create average sound pressure of 94-95dB 1Wmtr. With a 12" woofer I guess passive this means 50Hz cutoff in 70liter BR-enclosure.
To minimize horn coloration I choose a smaller horn like the ME10 and let the 6" go up to 3khz.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=294-618
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The most important reason to combine a 12" with a large waveguide is that of matching directivity. At frequencies between 1 and 2 kHz the beamwidth of the 12" matches the beamwidth of the waveguide. This will result in a smooth power response, which is desireable.
A 6" does not beam enough to match the directivity of the econowave waveguide at a crossover between 1 and 2 kHz.
Ok did not think of that thanks.
Here a sim. of the eminence 12LF. Like my guess it does in 70Liter 94dB 50Hz. The 18sound http://www.eighteensound.com/index.aspx?mainMenu=view_product&pid=243
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You hit the nail in the head
In fact, let's observe the same econowave being crossed at different frequencies:
XO point 2.5khz:
XO point 1.5khz
XO 1khz:
These were taken indoor, so not as accurate as some of my other measurements, but you get the idea
I think Helmuth is just point out that IF he is going 3 way then why not maximize the 3 way design by eliminating the issues of XO the horn too low and XOing the 12" woofer to high.
No doubt directivity is changed but I would like to see the charts of the 6.5" + Horn vs 12" + Horn. Then I welcome anyone to hear the two in a 3 way.
FWIW, I use a 12" (TD12M) in a three way myself but my CD can handle a lower XO (ie....looks like your 1KHz XO chart).
In the end I choose Sound Quality over directivity below 2KHz. Directivity isnt all that important at 1KHz or even 2KHz, IF we are sacrificing sound quality. The 6" will not colapse the directiivty either (narrowing it), it will create a wider band up to the XO which is not a bad thing at all since 99.9% of all other designs do that anyways.
No doubt directivity is changed but I would like to see the charts of the 6.5" + Horn vs 12" + Horn. Then I welcome anyone to hear the two in a 3 way.
FWIW, I use a 12" (TD12M) in a three way myself but my CD can handle a lower XO (ie....looks like your 1KHz XO chart).
In the end I choose Sound Quality over directivity below 2KHz. Directivity isnt all that important at 1KHz or even 2KHz, IF we are sacrificing sound quality. The 6" will not colapse the directiivty either (narrowing it), it will create a wider band up to the XO which is not a bad thing at all since 99.9% of all other designs do that anyways.
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Hi gainphile,You hit the nail in the head
In fact, let's observe the same econowave being crossed at different frequencies:
These were taken indoor, so not as accurate as some of my other measurements, but you get the idea
What mls-program is that that makes a sonogram?
Helmuth,
Andi (Gainphile) uses Arta. I know that because I know Andi, and also because it's on the charts!
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You could do a 3 way and still get CD. With a 6" if you cross at 2k to a 6" waveguide with 90 deg dispersion then you can get CD above that point fairly well. The advantage is that you can use tweeters that may not handle a lower xo point, perhaps a ribbon might handle it, although in that case you have different dispersion.
With the 3 way you can have a dedicated mid and woofer, and each of those drivers will see a narrower bandwidth and less power. Choices also open up regarding the mid driver. With 6" mids you can have just about any driver material, even metal drivers. By the time you get to larger drivers, it's all paper. I don't know of any 12" aluminium mids!
Andi (Gainphile) uses Arta. I know that because I know Andi, and also because it's on the charts!
---
You could do a 3 way and still get CD. With a 6" if you cross at 2k to a 6" waveguide with 90 deg dispersion then you can get CD above that point fairly well. The advantage is that you can use tweeters that may not handle a lower xo point, perhaps a ribbon might handle it, although in that case you have different dispersion.
With the 3 way you can have a dedicated mid and woofer, and each of those drivers will see a narrower bandwidth and less power. Choices also open up regarding the mid driver. With 6" mids you can have just about any driver material, even metal drivers. By the time you get to larger drivers, it's all paper. I don't know of any 12" aluminium mids!
real 3 way
I think that many of the econowave and other 2 way horn builders are missing something significant. Horns are decade devices, above that they act more like transmission lines and this brings about all sorts of audible stuff (when you have heard the difference once, there is no going back.
This means a 400Hz horn can cause "trouble" above 4K, a 1K horn trouble above 10K. There are also considerations of the drivers needed for upper midrange lower highs and UHF.
I feel that the Econowave is a great start (if very deep bass is not the goal), but the next step is not the midrange, rather UHF above 10K. The next step is a 4 way - with sensible efforts for playback below 80Hz.
I think that many of the econowave and other 2 way horn builders are missing something significant. Horns are decade devices, above that they act more like transmission lines and this brings about all sorts of audible stuff (when you have heard the difference once, there is no going back.
This means a 400Hz horn can cause "trouble" above 4K, a 1K horn trouble above 10K. There are also considerations of the drivers needed for upper midrange lower highs and UHF.
I feel that the Econowave is a great start (if very deep bass is not the goal), but the next step is not the midrange, rather UHF above 10K. The next step is a 4 way - with sensible efforts for playback below 80Hz.
Attachments
Please share with us some measurements of the "trouble" that horns have when used beyond 1 decade of design frequency. Are you talking about frequency response artifacts, distortion artifacts, phase artifacts, or directivity artifacts?
XRK971,
the trouble as I see it covers quite a bit of issues.
When a horn is asked to reproduce above the decade, it turns into a transmission line with serious resonance issues. As we are talking about a horn, the acoustic length varies with frequencies - smearing the problem over a great frequency range (above the decade). I find it impossible to integrate the artificial UHF pressure to the HF.
Distortion is a big subject and I am not convinced that it as a number correlates to what we hear.
Phase is also a subject that is not well understood - otherwise there would not be so many terribly misaligned speakers out there. In any case, due to horn gain, we have to EQ something out to extend the response. This most certainly causes audible phase artifacts in the pass band.
Directivity considerations are more like religious topics than scientific. Our rooms are not uniformly reflective across a wide band of frequencies, therefore in my book the necessity for uniform dispersion has to consider the environment and listening habits. I personally prefer very wide dispersion at UHF. My ears seem to get more of what I hear in real concert halls - a total randomness of UHF.
Funny enough, all of the things that you mention are things easily solved, but only from the beginning. There is no patch for resonance, distortion, phase or directivity.
Nate,
the horns started life as Faital Tractrix LTH142s. I added a MDF ring roughly corresponding to the LeCleach roundover. I then added 3KG of damping each and then painted them red with a textured roller. I really like what they do and don't do.
Zilch and the rest of the Econowave parents had as a primary design criteria putting less screwed up sound in the hands of the DIYourselfer. They succeeded admirably. Many myths were easily proved as such. Those that actually built them discovered that a good 12" midwoofer is no where as midrange challenged as the yellow cone fraction often paints them. They also discover how wonderful it is to have real acoustic output where music demands it most. They learn that horn honk is an artifact of misuse and not inherent in that topology. The +95dB efficiency all the way down to the midbass gives the owner access to a far greater spread of amplifiers - even true class A. That has considerable advantages too. I can't think of better value for the money! The next step in my opinion is UHF. Once the UHF is properly integrated, it is far easier then to get the LF to integrate - much easier than the other way around!
In my opinion, a 6" midrange is about as contraproductive as it could be for an Econowave. I tried a JBL LE8T2 for about a day with a variety of crossover points and amps - no luck, not even close. If there is a need for improvement in the midrange, this will only happen with a redesign of the entire system. A large horn covering from 150/200Hz to 1K/1.5K is the next logical step, but a big departure from the original design goal. Here is a fine example how this direction could look like:
http://www.lagrandecastine.fr/eng/leconcept.html
the trouble as I see it covers quite a bit of issues.
When a horn is asked to reproduce above the decade, it turns into a transmission line with serious resonance issues. As we are talking about a horn, the acoustic length varies with frequencies - smearing the problem over a great frequency range (above the decade). I find it impossible to integrate the artificial UHF pressure to the HF.
Distortion is a big subject and I am not convinced that it as a number correlates to what we hear.
Phase is also a subject that is not well understood - otherwise there would not be so many terribly misaligned speakers out there. In any case, due to horn gain, we have to EQ something out to extend the response. This most certainly causes audible phase artifacts in the pass band.
Directivity considerations are more like religious topics than scientific. Our rooms are not uniformly reflective across a wide band of frequencies, therefore in my book the necessity for uniform dispersion has to consider the environment and listening habits. I personally prefer very wide dispersion at UHF. My ears seem to get more of what I hear in real concert halls - a total randomness of UHF.
Funny enough, all of the things that you mention are things easily solved, but only from the beginning. There is no patch for resonance, distortion, phase or directivity.
Nate,
the horns started life as Faital Tractrix LTH142s. I added a MDF ring roughly corresponding to the LeCleach roundover. I then added 3KG of damping each and then painted them red with a textured roller. I really like what they do and don't do.
Zilch and the rest of the Econowave parents had as a primary design criteria putting less screwed up sound in the hands of the DIYourselfer. They succeeded admirably. Many myths were easily proved as such. Those that actually built them discovered that a good 12" midwoofer is no where as midrange challenged as the yellow cone fraction often paints them. They also discover how wonderful it is to have real acoustic output where music demands it most. They learn that horn honk is an artifact of misuse and not inherent in that topology. The +95dB efficiency all the way down to the midbass gives the owner access to a far greater spread of amplifiers - even true class A. That has considerable advantages too. I can't think of better value for the money! The next step in my opinion is UHF. Once the UHF is properly integrated, it is far easier then to get the LF to integrate - much easier than the other way around!
In my opinion, a 6" midrange is about as contraproductive as it could be for an Econowave. I tried a JBL LE8T2 for about a day with a variety of crossover points and amps - no luck, not even close. If there is a need for improvement in the midrange, this will only happen with a redesign of the entire system. A large horn covering from 150/200Hz to 1K/1.5K is the next logical step, but a big departure from the original design goal. Here is a fine example how this direction could look like:
http://www.lagrandecastine.fr/eng/leconcept.html
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