Hey I'm new to this forum and new to the speaker building scene.
I've really only designed 2 pairs of speakers, a open baffle mid speaker and standard 2 way main speakers, so really not that much experience in building. I have however modify alot of speakers, not that they sounded that good.
I have a bit of knowledge as I work for a electronic company and have worked in various hifi stores here in Aus.
I built a Pro series 3 poweramp from Jaycar a few years ago and wanted a decent pair of speakers to suit.
So I went looking on the net and found Fostex full range drivers.
Going on price I really didnt want to spend anymore than Aus$300.
So I ended up with the 4"103E.
I didnt know what I was going to do for a box until the speakers turned up, they had a slip included in the box with a loaded horn design. It looked like a challenge, so I started it.
Aus$90 for the cuts and 16mm MDF and $120 for the speakers.
Here is the pics of my build process.
I dont have a finish on the box yet, it will be vaneered with redgum.
Please tell me what you think.
I've really only designed 2 pairs of speakers, a open baffle mid speaker and standard 2 way main speakers, so really not that much experience in building. I have however modify alot of speakers, not that they sounded that good.
I have a bit of knowledge as I work for a electronic company and have worked in various hifi stores here in Aus.
I built a Pro series 3 poweramp from Jaycar a few years ago and wanted a decent pair of speakers to suit.
So I went looking on the net and found Fostex full range drivers.
Going on price I really didnt want to spend anymore than Aus$300.
So I ended up with the 4"103E.
I didnt know what I was going to do for a box until the speakers turned up, they had a slip included in the box with a loaded horn design. It looked like a challenge, so I started it.
Aus$90 for the cuts and 16mm MDF and $120 for the speakers.
Here is the pics of my build process.
I dont have a finish on the box yet, it will be vaneered with redgum.
Please tell me what you think.
These should be very enjoyable.
In case no one else says this, go easy on the stuffing or begin with a minimal amount.
Your basket treatment is interesting. It looks less messy than using
putty on the legs. However I can't see the seam. How was the foam cut and held in place.?
In case no one else says this, go easy on the stuffing or begin with a minimal amount.
Your basket treatment is interesting. It looks less messy than using
putty on the legs. However I can't see the seam. How was the foam cut and held in place.?
Putty on the basket legs and foam padding serve two very different purposes. The putty mass loads the legs thereby damping internal resonances. The foam blanket absorbs reflections bouncing around in the cabinet. My personal opinion is that 1/4-1/2" of putty is not going to do much, if indeed resonances in the legs is a problem to begin with. Also, if you put a reasonable amount of stuffing behind the driver, there is little in the way of reflections left to absorb at the driver.
Your treatment looks nice and I'm sure it does no harm, but it appears to be a solution in search of a problem.
YMMV
Bob
Your treatment looks nice and I'm sure it does no harm, but it appears to be a solution in search of a problem.
YMMV
Bob
Thanks for your comments.
The Putty I'm using is a speaker sealant from Jaycar, Ive used that in between the magnet and case. The foam I'm using is a honeycomb material sound absorbent mat, it has self adhesive backing.
I used as its easy to work with.
The Putty I'm using is a speaker sealant from Jaycar, Ive used that in between the magnet and case. The foam I'm using is a honeycomb material sound absorbent mat, it has self adhesive backing.
I used as its easy to work with.
Hey Bob you make a good point about the reflection and dampening on the speaker material I have used.
I was going of what I have seen and studied from the Net. Never thought about the property's of what there doing.
I wouldn't have thought the putty would make a difference being on a 4" driver, as there is not much going on compared to a 10" or 12".
This is all new to me, so your opinions are very welcome.
The speakers sound great to me, however when there is a person with a large voice comes on it becomes very ear piercing, almost to much top end or it cant handle the top end, I really dont know.
I mentioned this to an acquaintance who know's abit about speakers and suggested I do some testing with a parametric equalizer. Once i have the correct value use a notch filter to set in stone.
I was going of what I have seen and studied from the Net. Never thought about the property's of what there doing.
I wouldn't have thought the putty would make a difference being on a 4" driver, as there is not much going on compared to a 10" or 12".
This is all new to me, so your opinions are very welcome.
The speakers sound great to me, however when there is a person with a large voice comes on it becomes very ear piercing, almost to much top end or it cant handle the top end, I really dont know.
I mentioned this to an acquaintance who know's abit about speakers and suggested I do some testing with a parametric equalizer. Once i have the correct value use a notch filter to set in stone.
shporsche said:
I'm not sure what you mean by a person with a large voice, but I do know that this driver has a strong peak at 7kHz. This is right where the sibilance is with spitty singers. Put a 6dB cut at 7kHz and see how that sounds.
Bob
Bob Brines said:
Thanks Bob, I will try that now.
In regards to the large voice, I mean a powerful singer.
i.e Radney Foster, Elton John, Christina Aguilera all have powerful voices.
When they are really singing, right on there vocal limit it can sound piercing.
Bob Brines said:
Please ignore my ignorance, how do I achieve a 6db cut at 7kHz?
With a choke, notch filter?
If Notch what do I require? caps, coils, resistors.
What values do they need to be?
Thanks guys for your help.
shporsche said:
OK. This sounds like clipping or cone break-up. Hard to diagnose half a world away from a verbal description. It could be that you are over driving your amp, the speakers, or it could be just crappy CD's. Does the distortion go away when you back the volume down? Are you corner loading your speakers?
Bob
shporsche said:
You will need a notch filter -- cap, coil and resistor in parallel. Designing this trap will require some measurements and simulations. Perhaps you can locate someone who has already tackled this driver.
Bob
Bob Brines said:
Thanks Bob,
I did quite abit of searching on the net and found quite a few simple converters to give me the values I need.
I played with what I had last night, and found its dulling the sound to much. So I will play with some different values tonight.
I used a 33uf non pol crossover cap, 2R7 1 watt resistor and 0.82mH inductor.
And so it begins
🙂
Bob Brines said:
Yes its crappy CD and MP3 I'm using, the speakers are sitting in front of a big pair of 15" dual concentric Tannoy's.(sorry about the name dropping, but I love the Tannoy's)
A friend from work has a 200w bar radiator resistor (I think that's what its called) and send some signal through the notch to get a smooth curve and the exact value I need.
That may not make sense, sorry.
Ive played with the 103e extensively. It does not need any electrical filtration if properly setup. Instead it can be a remarkably flat driver in the midrange to top end. Of course, it is a very revealing driver, and you will likely find yourself working out problems in much of the rest of your system.
I would try first yanking off all of the foam damping etc from the back of the cone. just leave it all bare bones. Instead using the little foam gasket included with the driver between the driver frame and baffle. This will take care of the majority of resonances in the driver frame.
Then back the driver mounting screws off a twitch too if they are down really tight. you want just enough torque there. too much and you will pull the frame itself to a higher resonant frequency.
Prettymuch, damping is a double edged sword, and a balanced approach is best when considering back loaded horns. What you are likely currently experiencing is a broad spectrum "suckout" in frequencies from having used too much damping. This damping is not affecting all frequencies in the same way, and the 7k bump might be a "leftover" of what the driver is supposed to be doing heard at normal amplitude compared to all the rest of the attenuated frequencies from your damping implimentation.
In general with damping, you will take care of certain frequencies and anomolies, but you will simultaneously hurt the sound in other ways. I am not familiar with the wood, glue or enclosure design you are using etc so I would just say trial and error for finding the right damping amount, type and placement.
It will take a patient approach. You won't buy your way out of this one 🙂
cheers,
Clark
I would try first yanking off all of the foam damping etc from the back of the cone. just leave it all bare bones. Instead using the little foam gasket included with the driver between the driver frame and baffle. This will take care of the majority of resonances in the driver frame.
Then back the driver mounting screws off a twitch too if they are down really tight. you want just enough torque there. too much and you will pull the frame itself to a higher resonant frequency.
Prettymuch, damping is a double edged sword, and a balanced approach is best when considering back loaded horns. What you are likely currently experiencing is a broad spectrum "suckout" in frequencies from having used too much damping. This damping is not affecting all frequencies in the same way, and the 7k bump might be a "leftover" of what the driver is supposed to be doing heard at normal amplitude compared to all the rest of the attenuated frequencies from your damping implimentation.
In general with damping, you will take care of certain frequencies and anomolies, but you will simultaneously hurt the sound in other ways. I am not familiar with the wood, glue or enclosure design you are using etc so I would just say trial and error for finding the right damping amount, type and placement.
It will take a patient approach. You won't buy your way out of this one 🙂
cheers,
Clark
Hey Clark,
Thanks for your input, I have got the speakers finished now.
I gave these to a freind who has alot of experiance with speakers.
He ditched the filter I made and went back to the box, playing with dampening.
He got me to listen to them for hours while he played around with dampening.
They sound exactly how I want them, no more pitchy voice.
My conclusion is they sound great on classical, blues, jazz and slow rock.
House, dance, techno, rock, heavy metal and pop sound flat.
They certainly dont have much bass but when the bass is there its very tight.
Here is a few pics of them finished.
Thanks for your input, I have got the speakers finished now.
I gave these to a freind who has alot of experiance with speakers.
He ditched the filter I made and went back to the box, playing with dampening.
He got me to listen to them for hours while he played around with dampening.
They sound exactly how I want them, no more pitchy voice.
My conclusion is they sound great on classical, blues, jazz and slow rock.
House, dance, techno, rock, heavy metal and pop sound flat.
They certainly dont have much bass but when the bass is there its very tight.
Here is a few pics of them finished.
Fantastic work those look great!
I am glad you were able to get the sound right for you. indeed, the drivers are not perfect for everything, but what they do is wow city.
Later,
Clark
I am glad you were able to get the sound right for you. indeed, the drivers are not perfect for everything, but what they do is wow city.
Later,
Clark
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