Most important is the back directly behind the driver.
This is to try and prevent reflections to exit the cab through the cone with obvious deleterious effect.
It is also important to leave a clear path between woofer and port.
In your case it is a bit harder to reconcile the two.
If I see this correctly the port curls up the back panel. I would use 1 or 1.5" foam to cover the bottom and up to where the port ends and the back but leave a gap between the two to let the port work as it should.
I would think that if you make the gap near the port equivalent to port area you pretty much add the foam thickness to the port length so I would shorten it by that amount.
You can probably use thinner foam on the sides and I wouldn't bother with the baffle at all.
I use this stuff to fix foam to panels:
Everbuild 90805 Everproof DPM 908 5L: Amazon.co.uk: DIY & Tools
It's a rubberised bitumen compound usually used for damp-proofing.
Can be a bit messy and smells vaguely of a freshly tarmac'd road but it works well and is water-based so no nasty fumes.
May be I'm kinky but somehow I like the idea of having the inside of my cabs coated in rubber. ;-)
This is to try and prevent reflections to exit the cab through the cone with obvious deleterious effect.
It is also important to leave a clear path between woofer and port.
In your case it is a bit harder to reconcile the two.
If I see this correctly the port curls up the back panel. I would use 1 or 1.5" foam to cover the bottom and up to where the port ends and the back but leave a gap between the two to let the port work as it should.
I would think that if you make the gap near the port equivalent to port area you pretty much add the foam thickness to the port length so I would shorten it by that amount.
You can probably use thinner foam on the sides and I wouldn't bother with the baffle at all.
I use this stuff to fix foam to panels:
Everbuild 90805 Everproof DPM 908 5L: Amazon.co.uk: DIY & Tools
It's a rubberised bitumen compound usually used for damp-proofing.
Can be a bit messy and smells vaguely of a freshly tarmac'd road but it works well and is water-based so no nasty fumes.
May be I'm kinky but somehow I like the idea of having the inside of my cabs coated in rubber. ;-)
Ha, that sounds like a good idea actually. Amazon is amazing, I'll get some of that shipped out forthwith. Got every other piece of material I need, and I'll post pics of progress and completed project if anyone is interested.
This tiny cab will be perfect for me with a terrible back. Then the heaviest thing I'll have will be my Upright Bass.
I only have two things left I am considering since you guys have been kind enough to provide me with help, suggestions and answers to the rest of my questions.
1.) Use Duratex on the outside of the box, rubber stackable corners just in case I decide to make a second one to stack on top. I'm putting two neutrik speakon parallel jacks in the back.
2.) Make a really unique pretty box by using really light pallet wood and putting it on the outside everywhere (except the baffle) and sanding it down and staining it, putting corners on it and possibly one piece of solid wood for the baffle? This is something someone I play with suggested because they thought it would make a pretty box, and true it wouldn't add to the weight much or size, and would look incredibly unique while protecting the integrity of the box beneath, but solid wood (Oak, Cherry, Mahogany) on the baffle? I know it is a complete no-no to build a box with solid wood due to flexing etc and cracks along with ability to handle humidity etc, I feel like this is a bad idea and good old Duratex is prolly the way to go. Any thoughts?
On second thought maybe I will just find a pretty piece of birch plywood and forget any other type of wood as a veneer.
I just love woodwork and the look of it, I refinished a 74 Gibson Grabber and did 16 coats of Tung Oil, finishing with Micromesh 12000 grit, my god it looked so pretty, like glass on the outside magnifying every grain with a soft warmth.
This tiny cab will be perfect for me with a terrible back. Then the heaviest thing I'll have will be my Upright Bass.
I only have two things left I am considering since you guys have been kind enough to provide me with help, suggestions and answers to the rest of my questions.
1.) Use Duratex on the outside of the box, rubber stackable corners just in case I decide to make a second one to stack on top. I'm putting two neutrik speakon parallel jacks in the back.
2.) Make a really unique pretty box by using really light pallet wood and putting it on the outside everywhere (except the baffle) and sanding it down and staining it, putting corners on it and possibly one piece of solid wood for the baffle? This is something someone I play with suggested because they thought it would make a pretty box, and true it wouldn't add to the weight much or size, and would look incredibly unique while protecting the integrity of the box beneath, but solid wood (Oak, Cherry, Mahogany) on the baffle? I know it is a complete no-no to build a box with solid wood due to flexing etc and cracks along with ability to handle humidity etc, I feel like this is a bad idea and good old Duratex is prolly the way to go. Any thoughts?
On second thought maybe I will just find a pretty piece of birch plywood and forget any other type of wood as a veneer.
I just love woodwork and the look of it, I refinished a 74 Gibson Grabber and did 16 coats of Tung Oil, finishing with Micromesh 12000 grit, my god it looked so pretty, like glass on the outside magnifying every grain with a soft warmth.
Last edited:
Going by your use of measurements I assume you are in North America.
Don't know if you can get that stuff there but there is bound to be something similar at your local builders merchant.
As for the finish of your box I'd say it depends on what kind of gigs you do.
If you're in a Rockabilly outfit playing riotous yet dingy clubs Duratex is the obvious choice but if you're in a jazz band playing lounge bars wood would be nice.
Since you edited while I was typing (slowly) I'd say go with nice ply.
Don't know if you can get that stuff there but there is bound to be something similar at your local builders merchant.
As for the finish of your box I'd say it depends on what kind of gigs you do.
If you're in a Rockabilly outfit playing riotous yet dingy clubs Duratex is the obvious choice but if you're in a jazz band playing lounge bars wood would be nice.
Since you edited while I was typing (slowly) I'd say go with nice ply.
I for one would greatly appreciate your experiences once the thing is finished.
It just so happens that a good friend of mine is a bassplayer with a bad back who plays upright and electric.
It's either a small world or the bloody things are too heavy to play them for thirty years without getting back problems. ;-)
Ok, one last comment, and one way or another I am getting wood today and starting
From the source I have, here are the types of high-quality, very low void plywood I have available to me:
Cherry
Baltic Birch
White Oak
Red Oak
Walnut
Hickory
Maple
Alder
I decided I am going to end up staining the box, and I know everyone tends to recommend Baltic Birch, is it just simply the best so go with it if you can get it?
From the source I have, here are the types of high-quality, very low void plywood I have available to me:
Cherry
Baltic Birch
White Oak
Red Oak
Walnut
Hickory
Maple
Alder
I decided I am going to end up staining the box, and I know everyone tends to recommend Baltic Birch, is it just simply the best so go with it if you can get it?
Baltic birch ply tends to be high quality, void-free and cheaper than veneer-faced ply.
However they can have holes in the individual layers which will have been cut out and filled.
Veneer-faced ply should have an outer layer without these repairs which would show up if you stain. If the rest of the ply is of similar quality to baltic birch (ie lack of voids, number of layers) I'd go for that.
Another option is what is called 'Marine Ply' around here which is used for boat building (Surprise, surprise). It is also void-free but more expensive than baltic birch.
They use better, sea-water resistant glues for that.
However they can have holes in the individual layers which will have been cut out and filled.
Veneer-faced ply should have an outer layer without these repairs which would show up if you stain. If the rest of the ply is of similar quality to baltic birch (ie lack of voids, number of layers) I'd go for that.
Another option is what is called 'Marine Ply' around here which is used for boat building (Surprise, surprise). It is also void-free but more expensive than baltic birch.
They use better, sea-water resistant glues for that.
Fortunately found an amazing wood dealer 40 minutes away from me, better than previous sources (Much higher quality)
Shew Prices are in:
3/4" Void Free Top Grade 15 ply Baltic Birch - 66.66 4'x8' sheet (A lot cheaper than I thought it would be)
3/4" Void Free A-1 Grade African Mahogany (Mahogany Core) - 121.18
3/4" Void Free A-1 Grade Hickory Pecan (Hickory Pecan Core) - 78.45
3/4" Bamboo Strand Face/ Vertical Core Bamboo Plywood - 245.38
3/4 Cherry A-1 PS VC - 74.83
Currently, because I find it to be beautiful I am leaning towards African Mahogany. Although a Brindle Bamboo is exquisite, it is quite expensive.
Shew Prices are in:
3/4" Void Free Top Grade 15 ply Baltic Birch - 66.66 4'x8' sheet (A lot cheaper than I thought it would be)
3/4" Void Free A-1 Grade African Mahogany (Mahogany Core) - 121.18
3/4" Void Free A-1 Grade Hickory Pecan (Hickory Pecan Core) - 78.45
3/4" Bamboo Strand Face/ Vertical Core Bamboo Plywood - 245.38
3/4 Cherry A-1 PS VC - 74.83
Currently, because I find it to be beautiful I am leaning towards African Mahogany. Although a Brindle Bamboo is exquisite, it is quite expensive.
Pick the one you can justify to your wallet or wife. ;-)
That said the Mahogany seems reasonable but the bamboo not so much.
Although with bamboo you could claim that technically you made your bass cab out of grass but I'm not sure that a cheap joke would justify the price.
That said the Mahogany seems reasonable but the bamboo not so much.
Although with bamboo you could claim that technically you made your bass cab out of grass but I'm not sure that a cheap joke would justify the price.
I could go with a slightly smaller thickness (I didn't go with 1/2 inch because I was worried about having to brace it extensively since it is such a high power driver in such a small enclosure), either way with the ports glued in along the bottom, and the span being no more than 10" and 11" WxD, I think I will crossbrace just in the height section 8 inches up or about halfway. I have decided to finger join the edges of the box, and have decided to go with African Mahogany. Due to this I believe I will flush mount the baffle and just put a speaker grill cover on the 10" speaker leaving as much of the front exposed with a beautiful (I'm leaning towards Tung Oil) finish.
You'll get the most out of bracing if you use a different material and fix it using glue which does not set solid. I'd just use MDF for bracing and the bit which form the port.
In your drawing the baffle is inset. Have you considered setting it on?
(Hope you know what I mean!)
If you then round over the edges it'll give a bit more visual interest to the speaker with nice concentric and un-interupted lines in the corners.
But that's just my taste...
In your drawing the baffle is inset. Have you considered setting it on?
(Hope you know what I mean!)
If you then round over the edges it'll give a bit more visual interest to the speaker with nice concentric and un-interupted lines in the corners.
But that's just my taste...
Ah, I am glad you mentioned that, I actually changed my 3D CAD to reflect that already. I think with just the round grille on the speaker and exposed baffle, you are right, it will look exquisite with rounded corners and flush on every side instead of something inset. I love the way rounded edges look with finger joints too!
Materials and Parts:
African Mahogany 3/4" - $122 sheet 61$ used (enough for two cabs from one sheet)
Faital 10hp1020 - $275
EMINENCE BGH258 Bass Cabinet Super Tweeter - 39.99
Titebond II - I have a lot of this sitting around already but I think it's about 15 bucks for a 32 oz container
Wire - I have tons of this around too, so we will just say $10
Neutrik Speak on Jacks (2xparallel) - $6.75
L-Pad 50 Watt 8 ohm - $10.50
Solen 8 microfarad capacitor - $5.90
ERSE 0.51mH 14 AWG Perfect Layer Inductor Crossover Coil - $18.31
10 inch Speaker Grille - $12
Hinge - $2 (I am going to have a prop up stand underneath it that I make with some scrap hardwood)
Tung Oil - I have a lot of this sitting around too from various wood projects I'll put on about 12 coats and finish with micromesh 12,000 grit (yes 12K) so $20
Sandpaper and Polishing Materials - $10
Total Cost - $ 486.45
Result: 10"x11"x17" Naturally finished with Tung Oil Speaker Cabinet, 700 Watts @ 8 Ohms RMS, 1400 Watts Peak, hopefully sounding great pushin out just a couple hundred watts as well.
Materials and Parts:
African Mahogany 3/4" - $122 sheet 61$ used (enough for two cabs from one sheet)
Faital 10hp1020 - $275
EMINENCE BGH258 Bass Cabinet Super Tweeter - 39.99
Titebond II - I have a lot of this sitting around already but I think it's about 15 bucks for a 32 oz container
Wire - I have tons of this around too, so we will just say $10
Neutrik Speak on Jacks (2xparallel) - $6.75
L-Pad 50 Watt 8 ohm - $10.50
Solen 8 microfarad capacitor - $5.90
ERSE 0.51mH 14 AWG Perfect Layer Inductor Crossover Coil - $18.31
10 inch Speaker Grille - $12
Hinge - $2 (I am going to have a prop up stand underneath it that I make with some scrap hardwood)
Tung Oil - I have a lot of this sitting around too from various wood projects I'll put on about 12 coats and finish with micromesh 12,000 grit (yes 12K) so $20
Sandpaper and Polishing Materials - $10
Total Cost - $ 486.45
Result: 10"x11"x17" Naturally finished with Tung Oil Speaker Cabinet, 700 Watts @ 8 Ohms RMS, 1400 Watts Peak, hopefully sounding great pushin out just a couple hundred watts as well.
Since you are and very much unlike myself so organised we are expecting pictures now!
You've got plenty of time as I'll be away from my computer for 2-3 weeks soon but no pressure! ;-)
You've got plenty of time as I'll be away from my computer for 2-3 weeks soon but no pressure! ;-)
Well, It takes forever for me to formulate these things out in my head, right now I have to go get the plywood (its about 40 mins away) unfortunately I have to get it before 1 pm each day (it's a commercial place, and their customer showroom is only open to 1pm), and I work, so it will be Saturday before I can pick up the African Mahogany.
HOWEVER, that gave me some time to think about wiring. Should I include a Zobel Network? I suppose I had thought about a Notch filter too, which I am more than capable of putting in, but from my understanding I'd really need to test it with a mic in order to properly craft one (after the speaker is installed). So I suppose I can wait and add that in later, after I have someone test the various levels for me. Zobel network though?
Right now I was just going to do a simple 2 way 1st order Butterworth HPF
HOWEVER, that gave me some time to think about wiring. Should I include a Zobel Network? I suppose I had thought about a Notch filter too, which I am more than capable of putting in, but from my understanding I'd really need to test it with a mic in order to properly craft one (after the speaker is installed). So I suppose I can wait and add that in later, after I have someone test the various levels for me. Zobel network though?
Right now I was just going to do a simple 2 way 1st order Butterworth HPF
Hi,
You simply only need a 2nd order Butterworth @ 2.5KHz on the tweeter.
You don't need Zobels. Due to the L-pad, you can use a x/o calculator.
5.6uF series, 0.7mH parallel (air core), then L-pad, then tweeter.
A notch filter ? Do do what ?
rgds, sreten.
FWIW no way will that driver handle 700W without a high pass filter.
Bass power handling will about excursion limits, not thermal limits.
You simply only need a 2nd order Butterworth @ 2.5KHz on the tweeter.
You don't need Zobels. Due to the L-pad, you can use a x/o calculator.
5.6uF series, 0.7mH parallel (air core), then L-pad, then tweeter.
A notch filter ? Do do what ?
rgds, sreten.
FWIW no way will that driver handle 700W without a high pass filter.
Bass power handling will about excursion limits, not thermal limits.
Last edited:
I'm with sreten on this one.
Don't overthink things. You're building an instrument speaker, not a studio monitor.
The one case where you can truly say if it sounds good to you it IS good!
If you have a look at the FRs of dedicated electric bass amp speakers they all a have a presence peak just like that Eminence tweeter. With the Lpad you can adjust the severity of that peak. It should have an effect similar to changing drivers if you had ready-made cabs. Keep the rest as simple as possible. The less is in there the less can go wrong.
Don't overthink things. You're building an instrument speaker, not a studio monitor.
The one case where you can truly say if it sounds good to you it IS good!
If you have a look at the FRs of dedicated electric bass amp speakers they all a have a presence peak just like that Eminence tweeter. With the Lpad you can adjust the severity of that peak. It should have an effect similar to changing drivers if you had ready-made cabs. Keep the rest as simple as possible. The less is in there the less can go wrong.
Update:
I managed to take a longer Lunch Break and run to the lumber yard and pick up plywood today. I was really looking forward to a mahogany box, but when I went there despite it being Grade A-1, there were a decent number of small noticeable voids on the cut end. So I picked up a sheet of 15 ply (yeah 15 ply, damn it's heavy) Baltic Birch. I believe I will stain it a little darker to bring out the grain, and then finish it. Going to cut and build either this weekend or next week.
Thank you guys for your advice, I have a tendency to over-complicate and over-think things. I have per your advisement changed my plans to 2nd order Butterworth crossover with the following components:
2 x ERSE 0.70mH 14 AWG Perfect Layer Inductor Crossover Coil
2 x Audyn Cap Plus 5.6uF 800V Double Layer MKP Metalized Polypropylene Foil Crossover Capacitor
and I will use the L-Pad mentioned in a previous post (already have it) for the tweeter.
I have some spare boards but I went ahead and got a PCB from Parts Express as well so it will look all nice and neat (even though noone will see it)
Made a finger-joint rig and am now ready to go with all parts. 🙂.
I'll update as soon as I start with pictures.
PS: By no stretch of the imagination do I need an 800v capacitor, just saw a lot of great reviews for the Audyn caps, so that is what I went with and that was what they had. Why do they do these such high voltage for audio applications, you would have to have a tremendous amount of power going through them.
I managed to take a longer Lunch Break and run to the lumber yard and pick up plywood today. I was really looking forward to a mahogany box, but when I went there despite it being Grade A-1, there were a decent number of small noticeable voids on the cut end. So I picked up a sheet of 15 ply (yeah 15 ply, damn it's heavy) Baltic Birch. I believe I will stain it a little darker to bring out the grain, and then finish it. Going to cut and build either this weekend or next week.
Thank you guys for your advice, I have a tendency to over-complicate and over-think things. I have per your advisement changed my plans to 2nd order Butterworth crossover with the following components:
2 x ERSE 0.70mH 14 AWG Perfect Layer Inductor Crossover Coil
2 x Audyn Cap Plus 5.6uF 800V Double Layer MKP Metalized Polypropylene Foil Crossover Capacitor
and I will use the L-Pad mentioned in a previous post (already have it) for the tweeter.
I have some spare boards but I went ahead and got a PCB from Parts Express as well so it will look all nice and neat (even though noone will see it)
Made a finger-joint rig and am now ready to go with all parts. 🙂.
I'll update as soon as I start with pictures.
PS: By no stretch of the imagination do I need an 800v capacitor, just saw a lot of great reviews for the Audyn caps, so that is what I went with and that was what they had. Why do they do these such high voltage for audio applications, you would have to have a tremendous amount of power going through them.
Last edited:
- Status
- Not open for further replies.