Greetings fellow Bass-Heads,
I just couldn't wait any longer so here are a couple of pics of my first DIY Speaker project.
I'll be doing an extensive write up as well as posting plans after AES/BAF.
Please don't post links to this on other forums just yet.
-Matt
I just couldn't wait any longer so here are a couple of pics of my first DIY Speaker project.
I'll be doing an extensive write up as well as posting plans after AES/BAF.
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.
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.
Please don't post links to this on other forums just yet.
-Matt
more pics
Here is a few more images:
Transfer function with filter settings from WinISD
Cabinet rear with acrylic cover to show the guts and for smoke turbulence testing.
In this prototype version I didn't make an internal flare and did not cover the expanding foam void filler.
Clay molded "plug" for the external flare
Port mold__________________________________^
Here is a few more images:
Transfer function with filter settings from WinISD
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.
Cabinet rear with acrylic cover to show the guts and for smoke turbulence testing.
In this prototype version I didn't make an internal flare and did not cover the expanding foam void filler.
Clay molded "plug" for the external flare
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.
Port mold__________________________________^
An externally hosted image should be here but it was not working when we last tested it.
Smaart measurements
Here are some measurements I took in my garage (read very echoic) with a 50ohms sense resistor for impedance and A DBX reference mic for the frequency response both using a macbook pro, presonus 1818, a demo of smaart 7. Pink is impedance, blue is on axis in the ground plane at about 2 feet, and green is on axis at the mid point between the woofer and the port 16" away.
The large ripples in the freq. response are mirrored 1 octave up so I assume they are standing waves/room modes.
The impedance plot puts the Fb between 33 and 34, So great success there especially considering I made the port by hand and I was expecting it to be off by a much larger margin. I wonder what the response would look like with out room gain but that's hard for me to get as I live near the freeway in San Francisco.
Please post any comments, questions, and suggestions. I've been in the sound biz for a while, but this is my first build.
Here are some measurements I took in my garage (read very echoic) with a 50ohms sense resistor for impedance and A DBX reference mic for the frequency response both using a macbook pro, presonus 1818, a demo of smaart 7. Pink is impedance, blue is on axis in the ground plane at about 2 feet, and green is on axis at the mid point between the woofer and the port 16" away.
An externally hosted image should be here but it was not working when we last tested it.
The large ripples in the freq. response are mirrored 1 octave up so I assume they are standing waves/room modes.
The impedance plot puts the Fb between 33 and 34, So great success there especially considering I made the port by hand and I was expecting it to be off by a much larger margin. I wonder what the response would look like with out room gain but that's hard for me to get as I live near the freeway in San Francisco.
Please post any comments, questions, and suggestions. I've been in the sound biz for a while, but this is my first build.
port 2.0
The port for Prototype B is coming along.
An externally hosted image should be here but it was not working when we last tested it.
The port for Prototype B is coming along.
Oops...
Doh! Wrong link in last post. Here are the images
Doh! Wrong link in last post. Here are the images
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.
Matt,
Interesting that your cabinet seems to have a more pronounced port resonance than my Lab 2x12" box:
FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems
My outdoor (mic on ground 2 meters from cabinet front) plot below with yours for comparison. Other than the port resonance, response looks very similar.
Why did you make the cabinet front arced?
Art
Attachments
Hi Art,
I'm really glad you chimed in and shared your results in this thread for comparison. The results are very interesting. I'll take some time comparing these results with our design dimensions as I'm sure there is some valuable insight there. My initial thoughts are that your ports are greater than a 1/4 wavelength apart for 290Hz-350Hz so the response should vary with distance in that range. My ports are just inside a 1/4 wavelength apart (center to center) for 300 so the resonance effects are couple probably coupling.
In this prototype I didn't install an internal flare due to time constraints and there is a sharp edge at the top inside of the port. I suspect the turbulence coming from this would tend to excite any resonances greatly. I really need an outdoor measurement to get a better idea of whats going on, but I'm pretty close to completing the second prototype and I live in a very noisy area so that will have to wait.
The curved baffle came from my thoughts on making a medium-large array out of small cabinets. My concern is that increased low end from clustering would drown out the frequencies near the top of the subs band. One of of balancing this would be to increase the baffle area of the array to increase the directionality of the top end and level the response a bit towards the audience. I thought that perhaps using an arc instead of a plane would give me the area I needed with out increasing the size of the box. So when arrayed the arcs could align by angling adjacent in. This would also reduce the distance between the woofer radiating surface and might add to the coupling of the higher frequencies. I started modeling it in sketchup and really became attached to the look of the stacks. Then I did some math and it appeared that the effects I was hoping for would probably be negligible =(. But it still had a unique attractive appearance so I figured I would try it out.
I have run horn loaded subs like the TH-115 and the Bassmaxx Trip angled in with the mouths together and was pleased with the sound so my hopes are it won't make things worse. The setup with 6 per side ground stacked 2x3 with the mains on top will really stand out from all the other system in my area; I'm pretty excited about it.
-Matt
I'm really glad you chimed in and shared your results in this thread for comparison. The results are very interesting. I'll take some time comparing these results with our design dimensions as I'm sure there is some valuable insight there. My initial thoughts are that your ports are greater than a 1/4 wavelength apart for 290Hz-350Hz so the response should vary with distance in that range. My ports are just inside a 1/4 wavelength apart (center to center) for 300 so the resonance effects are couple probably coupling.
In this prototype I didn't install an internal flare due to time constraints and there is a sharp edge at the top inside of the port. I suspect the turbulence coming from this would tend to excite any resonances greatly. I really need an outdoor measurement to get a better idea of whats going on, but I'm pretty close to completing the second prototype and I live in a very noisy area so that will have to wait.
The curved baffle came from my thoughts on making a medium-large array out of small cabinets. My concern is that increased low end from clustering would drown out the frequencies near the top of the subs band. One of of balancing this would be to increase the baffle area of the array to increase the directionality of the top end and level the response a bit towards the audience. I thought that perhaps using an arc instead of a plane would give me the area I needed with out increasing the size of the box. So when arrayed the arcs could align by angling adjacent in. This would also reduce the distance between the woofer radiating surface and might add to the coupling of the higher frequencies. I started modeling it in sketchup and really became attached to the look of the stacks. Then I did some math and it appeared that the effects I was hoping for would probably be negligible =(. But it still had a unique attractive appearance so I figured I would try it out.
I have run horn loaded subs like the TH-115 and the Bassmaxx Trip angled in with the mouths together and was pleased with the sound so my hopes are it won't make things worse. The setup with 6 per side ground stacked 2x3 with the mains on top will really stand out from all the other system in my area; I'm pretty excited about it.
-Matt
I must say I have been following the threads your into and other things are just not as interesting anymoreBut these are not horns
Just so my comments not taken out of perspective I will clarify. "Not as", as in other things have been catching my eye lately. Theres good reason I'm following this thread, I am interested and enthusiastic about it, theres some nice work being done here. Apologies if I have detracted detracted from you thread Matt.
Yes this is not a horn
Dan,
I only referred to the angled configuration with horns to provide more back ground on where my idea's came from. Having stacked speakers like this before got me thinking and I came to some conclusions based on what I think reasonable logic. My comments quoted above are my attempt to put this in to perspective as I wouldn't want others to mistakenly take what I wrote as fact.
So to summarize, I got the idea of the curved baffle/array from angling horns towards each other, I have some thoughts on potential benefits to the sound in this vented design, but in the end it was an aesthetic decision to use it.
I think I was unclear and a bit wordy so I can understand your misinterpretation.
Blossom,
no apologies necessary and thanks for the encouragement. I've spent a long time reading up on this forum (and others) but didn't post much because I felt I should do more research. I have to admit I was a bit intimidated. I finally have something I want to share with the community I learned from, but with 750 views and only a few replies to go off of, I'm not sure what people think. So it's nice to have you show your support.
I'll be starting a full build thread with plans the first week of November. I just wanted to put this up as a bit of a sanity check between my first and second prototypes. So Dan's reply isn't exactly uncalled for, though I was hoping for more like Art's.
Oh and here's a new model:
Dan,
I only referred to the angled configuration with horns to provide more back ground on where my idea's came from. Having stacked speakers like this before got me thinking and I came to some conclusions based on what I think reasonable logic. My comments quoted above are my attempt to put this in to perspective as I wouldn't want others to mistakenly take what I wrote as fact.
So to summarize, I got the idea of the curved baffle/array from angling horns towards each other, I have some thoughts on potential benefits to the sound in this vented design, but in the end it was an aesthetic decision to use it.
I think I was unclear and a bit wordy so I can understand your misinterpretation.
Blossom,
no apologies necessary and thanks for the encouragement. I've spent a long time reading up on this forum (and others) but didn't post much because I felt I should do more research. I have to admit I was a bit intimidated. I finally have something I want to share with the community I learned from, but with 750 views and only a few replies to go off of, I'm not sure what people think. So it's nice to have you show your support.
I'll be starting a full build thread with plans the first week of November. I just wanted to put this up as a bit of a sanity check between my first and second prototypes. So Dan's reply isn't exactly uncalled for, though I was hoping for more like Art's.
Oh and here's a new model:
An externally hosted image should be here but it was not working when we last tested it.
Hi Matt
Curving the array in an inverted arc can widen the radiation pattern at 100Hz.
This reduces the beaming effect compared with a flat array. Maybe that is what you noticed.
Rog Mogale from Void Accoustics has an article on arraying bass cabinets here...
http://www.voidaudio.com//pdf/bass guide.pdf
Nice Build
Regards Martin (Xoc1)
Build decision
Thanks Dan and Martin,
Dan - The purpose of this build was in part to make a small speaker that works well in many situations and also to design and build my first cabinet. While I am pretty ambitious with what I'm trying to tackle, like most beginners are, I opted to gain a bit of experience before tackling a horn design. Rest assured there is one in my future =D.
-Xo Thanks for the link. I had a guild by EV on Bass Arrays but not this one. I love collecting audio pdfs as much as reading them.
-Matt
Thanks Dan and Martin,
Dan - The purpose of this build was in part to make a small speaker that works well in many situations and also to design and build my first cabinet. While I am pretty ambitious with what I'm trying to tackle, like most beginners are, I opted to gain a bit of experience before tackling a horn design. Rest assured there is one in my future =D.
-Xo Thanks for the link. I had a guild by EV on Bass Arrays but not this one. I love collecting audio pdfs as much as reading them.
-Matt
Matt,
Don't know how far you have gone in the curved array build, but the Lab 12s make a lot more bass (and way more upper bass) in a tapped horn than in a ported cabinet.
http://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers.html
You could still curve the Keystone fronts if you like that fiberglass smell
.By the way, testing at 2 meters it is not hard to get above traffic noise and get valid tests outdoors, I find my biggest problem for outdoor testing is wind noise, not traffic or the dogs
.Art
FML
This has gotten ridiculous...
I have put an insane amount time and money into this project and still the second prototype of my speaker isn't done
I didn't go to BAF. I barely spent time at the AES conference, I lost my job(that I hated and was going to quit eventually), I've hardly seen any of my friends or family, and I am in total shock that I am still alive because I'm sure my girlfriend(we live together) has wanted to kill me for a few months now.
Sigh.
I am going to finish and test this speaker tomorrow or die trying. Here's some pics. My attempts to make the fiberglass black kind of suck but oh well. I didn't take the time to resize the pictures so they are probably displayed wrong, but if you click on them hopefully they'll look normal.
-Matt
P.S. I've installed TH-118s in a night club in san francisco and I've used TH-115 extensively. I'm well aware of the benefits of the tapped horn but this if my first speaker I've ever designed and built so I decided to go bass reflex to gain some experience before venturing in to horns. It might save what little sanity I have left if no one else suggests I build a horn. Thanks for understanding.
This has gotten ridiculous...
I have put an insane amount time and money into this project and still the second prototype of my speaker isn't done
I didn't go to BAF. I barely spent time at the AES conference, I lost my job(that I hated and was going to quit eventually), I've hardly seen any of my friends or family, and I am in total shock that I am still alive because I'm sure my girlfriend(we live together) has wanted to kill me for a few months now.
Sigh.
I am going to finish and test this speaker tomorrow or die trying. Here's some pics. My attempts to make the fiberglass black kind of suck but oh well. I didn't take the time to resize the pictures so they are probably displayed wrong, but if you click on them hopefully they'll look normal.
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.
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.
-Matt
P.S. I've installed TH-118s in a night club in san francisco and I've used TH-115 extensively. I'm well aware of the benefits of the tapped horn but this if my first speaker I've ever designed and built so I decided to go bass reflex to gain some experience before venturing in to horns. It might save what little sanity I have left if no one else suggests I build a horn. Thanks for understanding.
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