BAMTM build thread

[savage25xtreme]

was ordering my goodies when I got to the tweeters I noticed madi is out of them. I am correct in assuming they are just out of stock and will get more in? SEAS Prestige 27TBFC/G madi part number H1212 is the correct tweeter right? any insight or alternate vendors would be appriciated.

Thanks

[ThomasW]

https://www.htguide.com/forum/showthread.php?t=33148

[savage25xtreme]

Thanks again Thomas. I will get some pics posted of the enclosure this weekend :T

[savage25xtreme]

quick update: ordered the crossover parts from madisound, the tweeters from meniscus, and the rest of the parts from partsexpress including Dayton binding posts and Acousta-Stuf and with shipping for everything to 73533 it came out to $300.74 if anyone else is interested is building these.

[HareBrained]

quick update: ordered the crossover parts from madisound, the tweeters from meniscus, and the rest of the parts from partsexpress including Dayton binding posts and Acousta-Stuf and with shipping for everything to 73533 it came out to $300.74 if anyone else is interested is building these.

You must have gotten the last pair of the 27's, Meniscus now lists it as out-of-stock.

[savage25xtreme]

I will consider myself lucky :W

I will put them to good use!

[cheno848]

I have a single H1212 if anybody only needs one.

Keep us updated on the build savage, I built a pair of these and love them.

[savage25xtreme]

I got all my MDF cut today, I am doing the 1cu-ft sealed like what is on Zaph's page. couple of questions. the baffle on the PE enclosure is 1/2" and mine is 3/4" can I do a 3/4 round over on the edge? or will it hit the drivers cut out? how big are the holes in the brace? spacing for holes in the brace? I did some research and found that binding posts are suppose to be 3/4" on center for spacing. I am going to do a 45 chamfer on the back of the driver cut outs, should I just do about the back 1/2" of the cut out? I downloaded the drivers spec sheets, are those really close on the holes sizes and flange thickness? should I use those measurements or wait til my drivers get here and measure myself?

Ill throw some pics in here tomorrow.

Thanks in advance,
Gavin

[savage25xtreme]

I found the drawing on the PE's website that has most of my answers.

[ThomasW]

should I use those measurements or wait til my drivers get here and measure myself?

One should always wait until the drivers are in hand...

[savage25xtreme]

ok, will do. how much of the back of the driver opening should i put a 45 degree on if my baffles are 3/4 thick? can you comment on that? I think I have found answers to all my other questions thus far.

[ThomasW]

Different drivers but the idea is the same...

[savage25xtreme]

So I called Meniscus today because my order still said "processing" and they said they are actually on back order there, probably for another week or two :evil: . could anyone point me in the direction of another vendor?

[drab]

I must have bought the last ones then. :twisted:

I ordered them last Monday from Meniscus and received them on Friday. :

Mike

[drab]

ThomasW

Is it ok to roundover the inside of the drivers' holes or
is it better to chamfer them?

Mike

[ThomasW]

http://www.zalytron.com/seas.html

chamfer or round-over, either one is fine.

[drab]

chamfer or round-over, either one is fine.

Thanks! :T

[savage25xtreme]

thanks for the link Thomas, got some routering and gluing done last night... I have a new respect for you guys that build perfect cabinets

I also learned the hard way to put the pivot pin for the circle jig down into your work bench so when you cut the last of the work piece it doesnt grab the side of your brace and go crazy... atleast I figured this out before I started on the baffles.

[savage25xtreme]

just called Zalytron and they had them in stock, you saved the day Thomas, and they were 20 cents cheaper 8) thanks again.

[savage25xtreme]

got my baffles and one of my cabinets done last night minus the sanding. on the baffle, once I glue it on I was going to round the edges over with a 3/4 round over so it will follow the cabinet profile perfectly... right now its a little big (about 1/16th all the way around). this will basically put the round over to within 1/4" of the edge of the driver cutouts. is that OK? would it be better to just do a 1/2 round over like the PE cabinets have? also my baffle is only 3/4 thick verses 1 inch thick on the PE cabinet.

any advice would be much appreciated on a rookies first build :T

[savage25xtreme]

also... would this be a better inductor to use for L2? with its much lower DCR for about the same price?

http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=266-902&ctab=1#Tabs

[ThomasW]

Buy a flush trim bit. It has a roller bearing on the bottom. Use it to make the edges flush with the panels.

!/2" vs 3/4" round-over isn't important

Do you really have a 3/4" roundover bit? Those only come with a 1/2" shafts.

Unless he screwed up (unlikely) Zaph calculated the resistance of the inductor into his design, so no don't change it.

[savage25xtreme]

in his options section he models this inductor with 3 different DCR values... as the resistance gets lower the sensitivity of the woofers gets better... and the least resistance value he plotted was .15 ohms. the one he specs out is .47ohms which has the worst sensitivity.

http://www.zaphaudio.com/BAMTM-modeled-L2DCRoptions.gif

I told some advice from Jim Holtz and all my bits are 1/2 shaft and whiteside. I have been extremely pleased with them thus far.

[drab]

He does have different dcr values as an option for L2. Lowering the dcr directly affects the Qts and sensativity.
He has measurements posted for different dcr values under options. You have to decide if it's worth the money.
For me it was worth the extra few bucks for my own mental stability.

Mike

Edit: You already knew this. :roll:

[savage25xtreme]

it was 16 dollars for the madisound sidewinder I got... the one in the link above is only 17 something...

I have been looking at your build pics drab, do you have a build thread somewhere?

[savage25xtreme]

quick update: my tweeters wont be here til lext tuesday but i got one of the cabinets done and one of the crossovers done and both baffles minus the tweeter holes of course.

45 degree i put on the back of the woofer holes



clamping the side and brace in





after the first woofer hole was cut i test fit a driver and it was too loose for my liking so i broke out the calipers and micrometer and got the next 3 holes to within .005 of the diameter of each driver.



how does this crossover look? inductors should be good according to the chart I saw somewhere.



having a blast :T

[Smokinghot]

after the first woofer hole was cut i test fit a driver and it was too loose for my liking so i broke out the calipers and micrometer and got the next 3 holes to within .005 of the diameter of each driver.

Sweet.... ;x(

[drab]

Wow! You're a better cabinet builder and photographer than I am. ;x(
Keep the pictures coming.

Mike

Ps: Nice bike. :T

[ThomasW]

45 degree i put on the back of the woofer holes

Thing is you need to leave enough 'meat' for the driver mounting screws.... that's why I posted this picture a while back...

[savage25xtreme]

kind of hard to see in the pic but I left about .3" on the front flat... with no 45 and the way it looks to me I will have a little over a half inch of meat. If it does not hold I have enough scrap to do 2 more baffles. Its all a learning process.

thanks for the kind words drab and smokinghot.

the bike is absolutely covered in MDF dust :P

Gavin

[savage25xtreme]

how do I know if they will hold? if with the gasket tape in there the drivers suck down to tight? any other signs I should look for?

I also just noticed my inductors ARE facing the wrong way.... DOH I'll fix it when I get home.

[HareBrained]

how do I know if they will hold? if with the gasket tape in there the drivers suck down to tight? any other signs I should look for?

I also just noticed my inductors ARE facing the wrong way.... DOH I'll fix it when I get home.

I believe Thomas is referring to the scalloped relief on his baffle verses the continuous chamber of yours. Behind the screws, his have a full baffle depth of holding power while yours is shallower.

[JonMarsh]

Really nice tight fit on for the drivers and baffle rabbet, but what if you want to paint the baffles? What then? :W

[savage25xtreme]

ya i realize what he is talking about, I just wasn't sure if mine will hold or should I start over?

[savage25xtreme]

Really nice tight fit on for the drivers and baffle rabbet, but what if you want to paint the baffles? What then? :W

I was going to put a coat black primer in the cut out then mask it off for painting the rest....will that not work?

[ThomasW]

I believe Thomas is referring to the scalloped relief on his baffle verses the continuous chamber of yours. Behind the screws, his have a full baffle depth of holding power while yours is shallower.

Those are baffles from one of Brandon's projects. You're correct about the scalloping, that's why I posted the pics.

[drab]

ya i realize what he is talking about, I just wasn't sure if mine will hold or should I start over?

I think it will hold just fine.

I was going to put a coat black primer in the cut out then mask it off for painting the rest....will that not work?

I think that will work too. :dancenana:

Mike

[savage25xtreme]

I got one of the crossovers done and mounted and got my tweeters in Friday so I decided to clamp one of the baffles on and set the drivers in there to make sure I wired everything right.... I was VERY pleased with how they sounded and I was way to close to the speaker and I only had one going... cant wait til they are both done :T





For these sealed enclosures should I put a bead of silicone around the inside to make sure they are sealed good?

[ThomasW]

For these sealed enclosures should I put a bead of silicone around the inside to make sure they are sealed good?

I usually do that. Instead of silicone I use a siliconized latex caulk. It's cheap, cleans up with water, and doesn't off-gas anything nasty.

[savage25xtreme]

I usually do that. Instead of silicone I use a siliconized latex caulk. It's cheap, cleans up with water, and doesn't off-gas anything nasty.

good deal I think I have some of that left over from a bathroom job. :B

[Mornlith]

Hey all..I've surfaced from my bathroom reno...now I can return to figuring out what to build.

Savage: What are you going to use the BAMTM's for? HT? If so, what are you going to do for a CC? Just curious. Build looks sweet so far. I noticed some Polk's in one of your pics and would be curious to hear how the "budget" speakers compare.

[savage25xtreme]

I am probably going to put the BAMTMs in the garage with a CD player... and build some Statements for my HT room. I will be sure are write a full review when I get both build, but they are going to blow my lil polks away. I picked those polks up for 200 bucks at Fry's on sale one day... they just barely make enough noise to be called speakers haha

I have a very hard time turning my one BAMTM off last night, so much fun to hear little details I have not heard. and i found that one of my burned copies of Tool 10,000 Days was a horrible copy, horribly staticy that I never heard on the polks. I feel this first DIY speaker build is the beginning of the end for me. I am hooked.

[savage25xtreme]

got the cabinets caulked up last night and both crossovers are now done and mounted. I used one screw right in the middle to mount them which holds them really well, and I don't think it will bother the inductors, or am I wrong? tonight I will stuff the cabinets and drill pilot holes for the drivers in the baffles then glue them on and start the finishing process.

one sack of AcoustaStuf should be enough for both cabinets right? any advice on how to put it in? on Zaph's website is just says stuff liberally and stay 5 inches from the midwoofers.

[savage25xtreme]

glue stuffing to the sides by that baffles? who knows?

[ThomasW]

glue stuffing to the sides by that baffles? who knows?

No need to do that. What you have done is fine.