Test baffle v2
Here are the schemes and the simulation (for the FR) of the design v2 of my test baffles, with measures.
They will be in 18mm plywood. There will be wings for the woofers, with composite panels to allow me to try (and measure) the following configurations:
1. front woofer, wing L 33cm, wing R 14cm
2. front woofer, wing L 14cm, wing R 14cm
3. front woofer, wing L 33cm, wing R 28cm
4. side woofer (external), wing front 33cm (this is the front baffle, that u see in the picture), wing back 14cm
5. side woofer (external), wing front 33cm, wing back 28cm
6. side woofer (internal), wing front 33cm (this is the front baffle, that u see in the picture), wing back 14cm
7. side woofer (internal), wing front 33cm, wing back 28cm
I dont think that firing the woofers in the center of the scene is the best idea. I havent seen it realized anywhere. But for the sake of curiosity I will try it.
I may not try all seven setups, if one appears particularly bad, making the wings shorter or longer wont change much - the numbers are small.
Thanks to Rudolf's help, I decifrated MJK formula to calcolate the U-frame resonance. I dont have a top panel, but with the shorter wings i can also lie over the short panel and see if imroves things. My guts tells me that I'm better off a top panel for the u-frame, so I dint order those panels.
Because of this air, the resonance will be very weak probably to the point that I wont need to damp or equalize at all.
The crossover point is estimated at 200hz. It is obvious that up to 300hz the FR drivers will need some boost and i'll do that in digital.
Another thing about woofers is that I'm going to get a couple of absorbing panels to put on the back walls from 0 to 60cm. Because they sell a box of 8 panels and I need only two, I'm looking for a group buy.
http://www.vicoustic.com/produtoInfo.asp?Id=39
This product has very good specs and should fix the fact that the back walls are only 50-60cm behind the woofers.
If not I still have the the ripole card to play
Here are the schemes and the simulation (for the FR) of the design v2 of my test baffles, with measures.
They will be in 18mm plywood. There will be wings for the woofers, with composite panels to allow me to try (and measure) the following configurations:
1. front woofer, wing L 33cm, wing R 14cm
2. front woofer, wing L 14cm, wing R 14cm
3. front woofer, wing L 33cm, wing R 28cm
4. side woofer (external), wing front 33cm (this is the front baffle, that u see in the picture), wing back 14cm
5. side woofer (external), wing front 33cm, wing back 28cm
6. side woofer (internal), wing front 33cm (this is the front baffle, that u see in the picture), wing back 14cm
7. side woofer (internal), wing front 33cm, wing back 28cm
I dont think that firing the woofers in the center of the scene is the best idea. I havent seen it realized anywhere. But for the sake of curiosity I will try it.
I may not try all seven setups, if one appears particularly bad, making the wings shorter or longer wont change much - the numbers are small.
Thanks to Rudolf's help, I decifrated MJK formula to calcolate the U-frame resonance. I dont have a top panel, but with the shorter wings i can also lie over the short panel and see if imroves things. My guts tells me that I'm better off a top panel for the u-frame, so I dint order those panels.
Because of this air, the resonance will be very weak probably to the point that I wont need to damp or equalize at all.
The crossover point is estimated at 200hz. It is obvious that up to 300hz the FR drivers will need some boost and i'll do that in digital.
Another thing about woofers is that I'm going to get a couple of absorbing panels to put on the back walls from 0 to 60cm. Because they sell a box of 8 panels and I need only two, I'm looking for a group buy.
http://www.vicoustic.com/produtoInfo.asp?Id=39
This product has very good specs and should fix the fact that the back walls are only 50-60cm behind the woofers.
If not I still have the the ripole card to play
Attachments
The woofers arrived!
***
First impressions
As rugged as they may be brand new on the floor, the bass is already punchy, and willing all voice range is within them with not clear ringing. Stellar price/performance ratio imo. Not that I have experience with many woofers, but I remember for instance the 2 10" pairs used in the Orions and I believe these are better.
They are being powered by the main posts of my Classé which has all the juice they need. Playing at moderate SPL for today. I planned to do the opposite phase trick and use pink noise, but instead i'm enjoying them playing! So they'll get music all the day and by the time i'll get the baffles, they should be burned in.
Another good thing is that my SMALL spades fit into the hole for wire/banana on the posts so I didn thave to buy adapters or new cables. I plan to use silver cables which I will build following a design that I have in mind, but now i dont have the time nor the money.
From now and then I'm adding also the FRs to give some more hours, but the frequence overlap without XO on the woofers is way too much. To make it acceptable, i'm using about -6db in the midrange and +6 at LF and +3 at HF. There is a slight sound pressure unbalance that favours the woofers about 2db (no big deal).
I can imagine that things will sound really good when everything will be setup. Unless the XTZ subamp is a piece of crap, but i doubt that
Next week will be busy but very interesting.
Pictures (they are now more further apart and closer to the baffles):
***
First impressions
As rugged as they may be brand new on the floor, the bass is already punchy, and willing all voice range is within them with not clear ringing. Stellar price/performance ratio imo. Not that I have experience with many woofers, but I remember for instance the 2 10" pairs used in the Orions and I believe these are better.
They are being powered by the main posts of my Classé which has all the juice they need. Playing at moderate SPL for today. I planned to do the opposite phase trick and use pink noise, but instead i'm enjoying them playing! So they'll get music all the day and by the time i'll get the baffles, they should be burned in.
Another good thing is that my SMALL spades fit into the hole for wire/banana on the posts so I didn thave to buy adapters or new cables. I plan to use silver cables which I will build following a design that I have in mind, but now i dont have the time nor the money.
From now and then I'm adding also the FRs to give some more hours, but the frequence overlap without XO on the woofers is way too much. To make it acceptable, i'm using about -6db in the midrange and +6 at LF and +3 at HF. There is a slight sound pressure unbalance that favours the woofers about 2db (no big deal).
I can imagine that things will sound really good when everything will be setup. Unless the XTZ subamp is a piece of crap, but i doubt that
Next week will be busy but very interesting.
Pictures (they are now more further apart and closer to the baffles):
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
rj...
the OBs are empty--I moved into a much smaller place and packed the drivers up.
The Spirit of Orion speakers are my attempt at an augmented OB design, Jordan JX92s drivers and a 12" M&K sub and 180 Watt/channel plate amp per speaker, as I presented in Affordable$$Audio some time ago.
Still love the JE Labs OB, just no space now...
here's a picture of the Spirits, when they still had some Altec drivers in them
the OBs are empty--I moved into a much smaller place and packed the drivers up.
The Spirit of Orion speakers are my attempt at an augmented OB design, Jordan JX92s drivers and a 12" M&K sub and 180 Watt/channel plate amp per speaker, as I presented in Affordable$$Audio some time ago.
Still love the JE Labs OB, just no space now...
here's a picture of the Spirits, when they still had some Altec drivers in them
Attachments
baffle v2 impressions
Lets start from the facts.
After two weeks during which I tinted the several little pieces of plywood, sanded and finally lacquered, 3 days ago I finally mounted the drivers in the baffles v2.
The panels were made exactly as designed by a very capable carpenter, which is now "my carpenter". As a first I put the longer wings, which are 33cm long, exactly as the front. Two of them (visible on the left speaker) have holes, which are filled by discs, taped in the inside. They were made this way to allow me to mount the woofers on the side.
But after I powered the speakers, the bass was so overwhelming and "right" that I'm not going to try a side-mounting. The issues of the back wall are way less than i have been told. Distance is only 70cm and CANNOT be more due to room furniture and listening position (center sear of a couch, at 1,9m).
At the same time, I cleared all the space behind the speakers. The Linns are in the right corner, which is a bit resonant area, and I think they help a bit like a bass trap.
Anyway measurements are still on the way: I tuned the speakers ALL by ear.
Below you see the picture of the current setup.
So, how they sound? Did the baffles v2 improved the Hemps?
You bet!
Let's start from the fullrange. The distortion is way lower. The ones who said that the pressed cardboard was culprit of most of it was right. Also, the EQ that i based on some measurements posted by a guy on diyaudio, NOW sounds right and they seem to fix most of the inherent non-linearities of the hemps.
I'm still considering finding better drivers for the task, but I dont feel the urge to anymore.
Now, the most amazing surprise. The bass. FANTASTIC. Much, much more that I expected. I started with the longer wings. Maybe I shouldnt have. I had to immediately reduce 8db on all the range (20-300hz) covered by the Beymas. Then, I also had to reduce the lowshelf @20hz of 10db to 8db. Whoever said that bass doesnt work in open baffle is an idiot.
I'm sure that my room compensate for most of the OB rolloff from 60 to 150hz and beyond. With the XTZ amp, i will probably not need any bass boost via software. Or i'll use just the latter, whichever sounds best.
Drivers on the floor play much softer, it is obvious, but the change has been dramatic also on the quality, the fullness. You need to look beyond the speakers to notice that there is no (closed) box. The bass is tight, fast, tuneful, as you would expect from the best speakers you can find.
Lastly, the blend between woofers and FR also improved from the positioning. The XO point remained at 300hz and I do not really feel a solution of continuity. A friend of mine told me that after I measure many things will change and the sound will improve. Curious to see which mistakes my ears have done
Next steps:
1) Measure everything
2) Improve the XO (try other stuff such as acourate) and DSP
3) Treat the back wall
For now, I'm just enjoying the music. For the first time in a LONG time, I can listen without earplugs.
Lets start from the facts.
After two weeks during which I tinted the several little pieces of plywood, sanded and finally lacquered, 3 days ago I finally mounted the drivers in the baffles v2.
The panels were made exactly as designed by a very capable carpenter, which is now "my carpenter". As a first I put the longer wings, which are 33cm long, exactly as the front. Two of them (visible on the left speaker) have holes, which are filled by discs, taped in the inside. They were made this way to allow me to mount the woofers on the side.
But after I powered the speakers, the bass was so overwhelming and "right" that I'm not going to try a side-mounting. The issues of the back wall are way less than i have been told. Distance is only 70cm and CANNOT be more due to room furniture and listening position (center sear of a couch, at 1,9m).
At the same time, I cleared all the space behind the speakers. The Linns are in the right corner, which is a bit resonant area, and I think they help a bit like a bass trap.
Anyway measurements are still on the way: I tuned the speakers ALL by ear.
Below you see the picture of the current setup.
So, how they sound? Did the baffles v2 improved the Hemps?
You bet!
Let's start from the fullrange. The distortion is way lower. The ones who said that the pressed cardboard was culprit of most of it was right. Also, the EQ that i based on some measurements posted by a guy on diyaudio, NOW sounds right and they seem to fix most of the inherent non-linearities of the hemps.
I'm still considering finding better drivers for the task, but I dont feel the urge to anymore.
Now, the most amazing surprise. The bass. FANTASTIC. Much, much more that I expected. I started with the longer wings. Maybe I shouldnt have. I had to immediately reduce 8db on all the range (20-300hz) covered by the Beymas. Then, I also had to reduce the lowshelf @20hz of 10db to 8db. Whoever said that bass doesnt work in open baffle is an idiot.
I'm sure that my room compensate for most of the OB rolloff from 60 to 150hz and beyond. With the XTZ amp, i will probably not need any bass boost via software. Or i'll use just the latter, whichever sounds best.
Drivers on the floor play much softer, it is obvious, but the change has been dramatic also on the quality, the fullness. You need to look beyond the speakers to notice that there is no (closed) box. The bass is tight, fast, tuneful, as you would expect from the best speakers you can find.
Lastly, the blend between woofers and FR also improved from the positioning. The XO point remained at 300hz and I do not really feel a solution of continuity. A friend of mine told me that after I measure many things will change and the sound will improve. Curious to see which mistakes my ears have done
Next steps:
1) Measure everything
2) Improve the XO (try other stuff such as acourate) and DSP
3) Treat the back wall
For now, I'm just enjoying the music. For the first time in a LONG time, I can listen without earplugs.
An externally hosted image should be here but it was not working when we last tested it.
at least they will not autodestroy collapsing the basket, like my audionirvana did when opened the windows and the experimental baffle went to the floor... 
now i'm drinking to forget and waiting for the markaudio, to come... really difficult to get something over the continents when you brother living abroad is too lazy...
now i'm drinking to forget and waiting for the markaudio, to come... really difficult to get something over the continents when you brother living abroad is too lazy...telstar which is the sensitivity of the fullrangers? does one woofer suffice for bass augmentation? if yes any particular reason about choosing the beyma? as clearly visible i'm in italy too and i have also some trouble finding the eminence or the goldwood drivers, not to talk of the pyles...
Sorry, I dint see this message before.
The estimated sensitivity of the hemps is 94db in my setup.
In a small room, under 20sq meters, one 12" is enough, yes. I have searched and evaluated woofers parameters (mostly 12") and as well tried to contain costs being this my first project. The Beymas are excellent drivers. One alternative is the Tone tubbies available in UK at a good price (but still much higher than my woofers). Models up in the Beyma range are also excellent.
I have to say that you cannot have very high SPL in the low-bass with a single driver in dipole/u-frame/h-frame. Equalization helps, but up to a point. Over 10db and the sound gets more dirty, I prefer less low-bass to that. For this reason I'm thinking of adding a pair of closed-box subwoofers to cover the first octave.
I'm not really sure what you could accomplish with other setups, but it seems to be general consensus to have 2 or 3 woofers per speaker to achieve high SPL at very low frequencies with dipole.
Update: No more updates
The subject means that basically the Hempatics project finishes here. I dont see margins of improvements that wont require the replacement of the Hemp drivers themselves, making the name void.
I'll make a new thread when will be the time.
I can sum up the balance, though.
Plus:
+Very low cost
+Sound quality like commercial speakers of 5-10 times more the cost
+Excellent bass from my POV
+Better transparency than ANY speaker I have ever heard, not considering price. (this thanks to direct connection to amps and software crossovers)
+Easy, seamless integration between the Beymas and the Hemps, both drivers are recommended, knowing their characteristics.
Minus:
-Fullrange drivers not particularly undistorted and with an annoying energy storage around 3k which hasnt been easy to tame
-Limits in reproduction of high harmonics
-Low SPL in the very low bass (under 60hz)
-Air/ambience could be improved with speakers with higher freq extension
-Wings size a bit too much that creates a little resonance around 250hz (can be fixed cutting the wings).
The future steps will be replacing the FR with unconventional widerange midrange transducers (top secret for the moment) + Heil AMT (Mundorf or Precide models) and the addition of a pair of closed-box subwoofers with peerless XXLS 10" to augment the very low bass (up to 50-60hz).
And obviously new baffles, with better finish, smaller wings and narrower on the top!
The reason for delays is that I'm waiting to get a state of the art DAC that will help me evaluate the new speakers that will come. I can only say that the name will be crazy.
Stay tuned.
The subject means that basically the Hempatics project finishes here. I dont see margins of improvements that wont require the replacement of the Hemp drivers themselves, making the name void.
I'll make a new thread when will be the time.
I can sum up the balance, though.
Plus:
+Very low cost
+Sound quality like commercial speakers of 5-10 times more the cost
+Excellent bass from my POV
+Better transparency than ANY speaker I have ever heard, not considering price. (this thanks to direct connection to amps and software crossovers)
+Easy, seamless integration between the Beymas and the Hemps, both drivers are recommended, knowing their characteristics.
Minus:
-Fullrange drivers not particularly undistorted and with an annoying energy storage around 3k which hasnt been easy to tame
-Limits in reproduction of high harmonics
-Low SPL in the very low bass (under 60hz)
-Air/ambience could be improved with speakers with higher freq extension
-Wings size a bit too much that creates a little resonance around 250hz (can be fixed cutting the wings).
The future steps will be replacing the FR with unconventional widerange midrange transducers (top secret for the moment) + Heil AMT (Mundorf or Precide models) and the addition of a pair of closed-box subwoofers with peerless XXLS 10" to augment the very low bass (up to 50-60hz).
And obviously new baffles, with better finish, smaller wings and narrower on the top!
The reason for delays is that I'm waiting to get a state of the art DAC that will help me evaluate the new speakers that will come. I can only say that the name will be crazy.
Stay tuned.
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