Nice work MV Angel, they look good. I'm with Sploo here though, I would have mounted the drivers from the front (particularly the tweeter). Did you sim the low end reponse in Winisd or something similar? That should help you get the best tuning for the enclosure.
Next project, a mid horn using a couple of toilets?...I'm sure someone has already done it 😀
Next project, a mid horn using a couple of toilets?...I'm sure someone has already done it 😀
MV...
Nice enclosure..I think out of the box thinking on enclosure structures is very refreshing.
On the problem of enclosure volume, couldn't you invert a second structure to double the volume?
Yes it is starting to look familiar and I think this shape is "common" but it might be doable?
What do you think?
_________________________________________________Rick........
Nice enclosure..I think out of the box thinking on enclosure structures is very refreshing.
On the problem of enclosure volume, couldn't you invert a second structure to double the volume?
Yes it is starting to look familiar and I think this shape is "common" but it might be doable?
What do you think?
_________________________________________________Rick........
Attachments
Ok, on the design consideration again:
In order to make sure I don't missus the driver and any "bad" sound comes from the ceramics I've copied the original mounting position of the drivers:
In the original ELAC EL 50 enclosure the drivers were recessed also and the mounting options with the rubber sear are actally made to internal mounting. This was teh reason to widen the hole for the tweeter and create a rounding on the opening. I could create the same for the woofer if it makes a difference...
On the same picture you could also see the original damping used in the ELACs. I'be reused it also. I was thinking to spray a thin layer of the polyurethane foam that would easily stick t the surface of the ceramic, has good on paper damping parameters 🙂
Yes, I've actually thought on such "double" shape but my criteria for not selecting it for the first attempt were purely based on of the feasibility of my design ideas. I was difficult enough to mix wood and ceramic on a smaller scale, so doubling the trouble was too much for the beginning 🙂 Now on the practicality, I my simulations by putting the same woofer in 20l instead of 10l I did not get too much of a improved response: instead of 70 it went to 50 Hz on the same level. Simulation was done with Bassbox.Yellow is 20l and blue is the current 10l internal volume.
So it was not work the double effort to create a 20kg + enclosure, more difficult to create and most of all not able to support itself standing 🙂 I guess this will be the next project.
now back to all your suggestions:
1. Recessed drivers: I could try to modify the baffle to flush mount them. However, due to the back mounting of the drivers, this would not leave any space for the bolts to screw the driver in place so no go for now...
2. Bigger enclosure from ceramic: only worth it with better driver (known T/S parameters for starter matching the 20 l volume) and again, if the ceramic has any future as experiments target.
I'll try to find some quiet place to do proper measuring of the speaker to determine whether its worth proceeding next.
In order to make sure I don't missus the driver and any "bad" sound comes from the ceramics I've copied the original mounting position of the drivers:
An externally hosted image should be here but it was not working when we last tested it.
In the original ELAC EL 50 enclosure the drivers were recessed also and the mounting options with the rubber sear are actally made to internal mounting. This was teh reason to widen the hole for the tweeter and create a rounding on the opening. I could create the same for the woofer if it makes a difference...
On the same picture you could also see the original damping used in the ELACs. I'be reused it also. I was thinking to spray a thin layer of the polyurethane foam that would easily stick t the surface of the ceramic, has good on paper damping parameters 🙂
Yes, I've actually thought on such "double" shape but my criteria for not selecting it for the first attempt were purely based on of the feasibility of my design ideas. I was difficult enough to mix wood and ceramic on a smaller scale, so doubling the trouble was too much for the beginning 🙂 Now on the practicality, I my simulations by putting the same woofer in 20l instead of 10l I did not get too much of a improved response: instead of 70 it went to 50 Hz on the same level. Simulation was done with Bassbox.Yellow is 20l and blue is the current 10l internal volume.
So it was not work the double effort to create a 20kg + enclosure, more difficult to create and most of all not able to support itself standing 🙂 I guess this will be the next project.
now back to all your suggestions:
1. Recessed drivers: I could try to modify the baffle to flush mount them. However, due to the back mounting of the drivers, this would not leave any space for the bolts to screw the driver in place so no go for now...
2. Bigger enclosure from ceramic: only worth it with better driver (known T/S parameters for starter matching the 20 l volume) and again, if the ceramic has any future as experiments target.
I'll try to find some quiet place to do proper measuring of the speaker to determine whether its worth proceeding next.
Attachments
OK....So the internal volume is almost exact, would preclude trying anything further ....Curious you are making this structure yourself from the ground up??
Cool, can you make any finish you want??Perhaps you could apply a painted wood grain type finish?? I was thinking a Burlwood type. I've seen them paint such appearances at a Auto Body shop I worked next to once upon a time.
The resonances of a porcelian like this must be very high....Don't you think?
Strike it gently with something metal.....I would say 700 Hz or so...As it has so much mass I doubt the drivers could possibly excite the enclosure into resonance. Myself I would line the inside with 1/8" cork material, with a suitable adhesive. Set up on stands or located on a bookshelf chin high would be great. A complimentary subwoofer & you'd be set!
______________________________________________Rick.........
Cool, can you make any finish you want??Perhaps you could apply a painted wood grain type finish?? I was thinking a Burlwood type. I've seen them paint such appearances at a Auto Body shop I worked next to once upon a time.
The resonances of a porcelian like this must be very high....Don't you think?
Strike it gently with something metal.....I would say 700 Hz or so...As it has so much mass I doubt the drivers could possibly excite the enclosure into resonance. Myself I would line the inside with 1/8" cork material, with a suitable adhesive. Set up on stands or located on a bookshelf chin high would be great. A complimentary subwoofer & you'd be set!
______________________________________________Rick.........
Attachments
No I am not making the ceramic shell, but rather re-using a easily available and affordable shape:
so called semi pedestal:
Semi Pedestal
The structure itself is very rigid , about 3 cm tick with
No I am not making the ceramic shell, but rather re-using a easily available and affordable shape:
so called semi pedestal:
Semi Pedestal
The structure itself is very rigid , about 3 cm tick with double walls even and I could not hear any ringing or audible resonance once it was closed. Still, let me check with some measuring tools to see what I cannot hear...
I hesitating to glue anything to the internal walls as this is going to reduce further the internal volume. Still searching around for the best option.
I have done the first preliminary measurements and I would like to share them with the community and ask for feedback.
The test setup is as follows:
1. Receiver Marantz SR-5400, set to stereo mode and only right channel connected. Setting for Large stereo speakers (full signal without crossover to the front speakers)
2. Source, my home theater PC, external USB creative SB live! connected via optical cable to the receiver
3. Measurements via audioTester: a very nice shareware tool
AudioTester
Measurements methodology:
I've disconnected the left channel and hooked up the speakers to the right only, as I was interested only at one speaker at a time, and the tool did not seem to work nicely for one speaker measurements only.
I would measure first my permanent speakers, Kef Q1, then swap them with the ELAC EL 50 in the original enclosure and then the ELAC EL 50 in my cerаmic DIY design.
Here are the results:
KEF Q1 reference measurements:
ELAC EL 50 in the original enclosure
ELAC EL 50 with ceramic enclosure
Before making my final conclusions, I would like to ask the following questions:
1. How do the measurements look like? Does this look ok? I know my living room is not the best measurements test bed, so I'be measured the KEF Q1 in order to see how a "normally good" speakers look like, but for me without any experience, the ceramic enclosure looks as good as the original enclosure.
2. What other measurements would I need to make in order to understand better the effect of the ceramic enclosures? I see the audioTester has distortion and impulse measurements, but what useful information would this give me?
3. How can I improve at this stage the results by looking at the graphs?
The test setup is as follows:
1. Receiver Marantz SR-5400, set to stereo mode and only right channel connected. Setting for Large stereo speakers (full signal without crossover to the front speakers)
2. Source, my home theater PC, external USB creative SB live! connected via optical cable to the receiver
3. Measurements via audioTester: a very nice shareware tool
AudioTester
Measurements methodology:
I've disconnected the left channel and hooked up the speakers to the right only, as I was interested only at one speaker at a time, and the tool did not seem to work nicely for one speaker measurements only.
I would measure first my permanent speakers, Kef Q1, then swap them with the ELAC EL 50 in the original enclosure and then the ELAC EL 50 in my cerаmic DIY design.
Here are the results:
KEF Q1 reference measurements:
An externally hosted image should be here but it was not working when we last tested it.
ELAC EL 50 in the original enclosure
An externally hosted image should be here but it was not working when we last tested it.
ELAC EL 50 with ceramic enclosure
An externally hosted image should be here but it was not working when we last tested it.
Before making my final conclusions, I would like to ask the following questions:
1. How do the measurements look like? Does this look ok? I know my living room is not the best measurements test bed, so I'be measured the KEF Q1 in order to see how a "normally good" speakers look like, but for me without any experience, the ceramic enclosure looks as good as the original enclosure.
2. What other measurements would I need to make in order to understand better the effect of the ceramic enclosures? I see the audioTester has distortion and impulse measurements, but what useful information would this give me?
3. How can I improve at this stage the results by looking at the graphs?
Attachments
The measurements of the KEF look to be suffering badly from comb filtering. This is usually caused by reflections from the side walls, floor and ceiling - basically, you need to do the following:
1) Perform the measurements where reflections will be reduced (perhaps outside), AND/OR
2) Perform the measurements with the mic closer to the speaker (and gate the data so that it discounts anything it picks up after the time it would take for the sound to travel from speaker to mic - i.e. to remove reflections). Note that this won't work well for bass frequencies.
The dip around 2kHz for the ELAC measurements are quite severe (>15dB). Again, I'd assume (hope) this was a room effect, and not an artifact of the speaker.
Finally, all measurements tail off very quickly by 7kHz. The speakers should be producing sound until around 20kHz. Is the testing program generating sound across the full 20Hz-20kHz range?
Basically, all these measurements look like they're being affected by the room so badly that you really need to change the measurement procedure (note - this is pretty normal for an untreated room).
As for using the readings to improve the speakers - I don't think you can do much with these measurements, but in time, you may find that impulse measurements will be useful. Without any internal damping, I'd expect to see some smearing on an impulse measurement (i.e. the mic measures the impulse from the speaker cone, then you'd see the reflection from the rear of the cone, that's bounced off the back of the enclosure and radiated through the cone material).
1) Perform the measurements where reflections will be reduced (perhaps outside), AND/OR
2) Perform the measurements with the mic closer to the speaker (and gate the data so that it discounts anything it picks up after the time it would take for the sound to travel from speaker to mic - i.e. to remove reflections). Note that this won't work well for bass frequencies.
The dip around 2kHz for the ELAC measurements are quite severe (>15dB). Again, I'd assume (hope) this was a room effect, and not an artifact of the speaker.
Finally, all measurements tail off very quickly by 7kHz. The speakers should be producing sound until around 20kHz. Is the testing program generating sound across the full 20Hz-20kHz range?
Basically, all these measurements look like they're being affected by the room so badly that you really need to change the measurement procedure (note - this is pretty normal for an untreated room).
As for using the readings to improve the speakers - I don't think you can do much with these measurements, but in time, you may find that impulse measurements will be useful. Without any internal damping, I'd expect to see some smearing on an impulse measurement (i.e. the mic measures the impulse from the speaker cone, then you'd see the reflection from the rear of the cone, that's bounced off the back of the enclosure and radiated through the cone material).
thank you sploo for the constructive and useful comments. Here are my answers:
Yep, this is my living room, quite irregular in shape and the speakers were located 30 cm from the rear wall, just next to a CRT TV. I will first try the same measurements in a different location.
The current crossover for the ELAC is at 3.5 kHz according to the manufacturer. Could this be the case also that there is something major wrong with the current drivers/xover setup?
Yes, the test signal was from 20 to 20 000 Hz, and I could hear the very low level avove 10 000 Hz. I would assume this is the problem of the mic. I am using a very basic creative PC mic, that I cannot even find any parameters for it. it could be the case the mic does not capture anything above 11k. As I don't have access to a better mic, I would have to think how to cope with this problem...
The case does have internal damping and the case is very rigid and very, very still. On any knocking there is no resonance nor ringing audible.
Ok, but even with all the comments, could I make a conclusion then that even with 20% less volume (10 liters instead of 12 liters) the ceramic enclosure due to its better rigidness and stiffness is having similar if not better audio quality? This would actually raise the questions if the volumes were equal, would the ceramic enclosure sound 20% better...
Yep, this is my living room, quite irregular in shape and the speakers were located 30 cm from the rear wall, just next to a CRT TV. I will first try the same measurements in a different location.
The current crossover for the ELAC is at 3.5 kHz according to the manufacturer. Could this be the case also that there is something major wrong with the current drivers/xover setup?
Yes, the test signal was from 20 to 20 000 Hz, and I could hear the very low level avove 10 000 Hz. I would assume this is the problem of the mic. I am using a very basic creative PC mic, that I cannot even find any parameters for it. it could be the case the mic does not capture anything above 11k. As I don't have access to a better mic, I would have to think how to cope with this problem...
The case does have internal damping and the case is very rigid and very, very still. On any knocking there is no resonance nor ringing audible.
Ok, but even with all the comments, could I make a conclusion then that even with 20% less volume (10 liters instead of 12 liters) the ceramic enclosure due to its better rigidness and stiffness is having similar if not better audio quality? This would actually raise the questions if the volumes were equal, would the ceramic enclosure sound 20% better...
Cool project!
Btw - Did you know that you can build a very cheap measurement microphone from $1.5 Panasonic electret capsules?
http://www.linkwitzlab.com/sys_test.htm#mic
http://phreakmonkey.com/projects/monkeyphones/
http://www.mp3forkidz.com/mic/mod.html
Btw - Did you know that you can build a very cheap measurement microphone from $1.5 Panasonic electret capsules?
http://www.linkwitzlab.com/sys_test.htm#mic
http://phreakmonkey.com/projects/monkeyphones/
http://www.mp3forkidz.com/mic/mod.html
> Yep, this is my living room, quite irregular in shape and the speakers were located 30 cm from the rear wall, just next to a CRT TV. I will first try the same measurements in a different location.
Without major absorption on walls/ceilings/floors (look up anechoic chambers) you really need to be thinking in terms of meters between the speaker and all surfaces (or use close micing [spelling?] plus a time gate).
> The current crossover for the ELAC is at 3.5 kHz according to the manufacturer. Could this be the case also that there is something major wrong with the current drivers/xover setup?
It's possible, but it would be pretty poor for that sort of dip. I'd hope it would be the room.
> and I could hear the very low level avove 10 000 Hz.
Do you mean you could only hear a low level above 10kHz from the speaker, or from the sound the mic had recorded?
If it's the mic, then you really will need a new one. I've been using a Behringer ECM8000 with their XENYX 802 mixer as a pre-amp.
Alternatively, you could make one from the links that kristleifur posted.
> then that even with 20% less volume (10 liters instead of 12 liters) the ceramic enclosure due to its better rigidness and stiffness is having similar if not better audio quality?
The air inside the box forms a 'spring' that damps the midbass driver, so I'd expect that a 20% in volume difference would have some effect (just how much would probably depend on the driver).
There's a good chance your ceramic enclosure is better than the original in terms of rigidity.
Note that the front baffle size (and location of the drivers of the baffle) may also have an effect. Look up "baffle step" to understand how the baffle causes a drop in sound level at a certain frequency. There are many many factors that affect how a speaker sounds.
Really dumb question - does the baffle seal tightly to the ceramic (i.e. you have no leaks)?
Without major absorption on walls/ceilings/floors (look up anechoic chambers) you really need to be thinking in terms of meters between the speaker and all surfaces (or use close micing [spelling?] plus a time gate).
> The current crossover for the ELAC is at 3.5 kHz according to the manufacturer. Could this be the case also that there is something major wrong with the current drivers/xover setup?
It's possible, but it would be pretty poor for that sort of dip. I'd hope it would be the room.
> and I could hear the very low level avove 10 000 Hz.
Do you mean you could only hear a low level above 10kHz from the speaker, or from the sound the mic had recorded?
If it's the mic, then you really will need a new one. I've been using a Behringer ECM8000 with their XENYX 802 mixer as a pre-amp.
Alternatively, you could make one from the links that kristleifur posted.
> then that even with 20% less volume (10 liters instead of 12 liters) the ceramic enclosure due to its better rigidness and stiffness is having similar if not better audio quality?
The air inside the box forms a 'spring' that damps the midbass driver, so I'd expect that a 20% in volume difference would have some effect (just how much would probably depend on the driver).
There's a good chance your ceramic enclosure is better than the original in terms of rigidity.
Note that the front baffle size (and location of the drivers of the baffle) may also have an effect. Look up "baffle step" to understand how the baffle causes a drop in sound level at a certain frequency. There are many many factors that affect how a speaker sounds.
Really dumb question - does the baffle seal tightly to the ceramic (i.e. you have no leaks)?
I'll try to make one or to borrow a "real mic"
Again, this is my first project, so I am still learning. I thank to you all who helped my in my learning curve. I hope for some more advice on how to improve this as a novice project.
The seal is working. The drivers have a rubber inside seal and the y are secured to the baffle with bolts from the inside.
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