Ported Blueprint 1503

[Bent]

Greetings:
I sent Kyle at Acoustic Visions a M.O. today - he'll return the favour in kind shortly by sending me a shiny new BP 1503 driver...
(Thanks for your patience, Kyle)

He (Kyle) indicated to me that the BP 1503 would work well in a 85 liter box, and ported in a 142 litre box. (I'm not doubting you Kyle, but what would a larger box do for me, assuming I set the port length(s) to suit?)
I ran the T/S parameters (minus the inductance values, 'cause I don't have them) through my download of Unibox and came up puzzled... ( I certainly didn't think Unibox was that in-depth, so there is a lot of stuff in it that goes way over my head). Where can I realistically expect my lower cut-off freq. to be at?

I intend to drive the BP with a amp in the 1kw neighborhood, but I'm thinking that that may be too much power in a ported box (I've settled on a ported design).

Can anybody offer any suggestions as what would power this unit the best?

Oh, I had one more question, how much volume will the '1503 occupy in the box so I can optimize my box size?

Ben.

[ThomasW]

Just copy this design or this design you'll find they are quite similar, and provide very good performance

[Bent]

Thomas, I was hoping the 1503 would work in a similar enclosure as the AS-15, as my reaction to viewing it the first time a number of months ago was almost X-rated!

The AS-15 wound up being very heavy, do you think you went overboard with the internal bracing, or does a driver like a BP 1503 require such ridgidity?

[ThomasW]

If I had it to do all over again I'd use Baltic ply instead of MDF for everything other than the front baffle. Unfortunately that won't have much impact on the weight.

The BP1503 needs the same cabinet construction as the HE-15. They're both high excursion drivers, that can handle tons of power.

If you want low weight built a tube sub.

[Bent]

Thanks for the reply - It has to/must be a box - so I'll have to deal with the high weight, I guess it's just the nature of the beast!!!

I'm getting very much wound up about this project.
I'll get a plate amp before I do any cutting of any lumber.

[Bing Fung]

Cool on the BP1503 Ben :T

Thats going to make one nice sub :yesnod:

Sorry I haven't got the landed cost to you yet as I haven't received my CC statement yet. No matter it seems as you just went with it :lol:

[Bent]

Yup, I got into a panick thinking the last one may go to someone else, so I ordered.

I'm going to build a copy of the AS-15 above, only out of cardboard!!! ROTFLOL.

[JonMarsh]

Yup, I got into a panick thinking the last one may go to someone else, so I ordered.

I'm going to build a copy of the AS-15 above, only out of cardboard!!! ROTFLOL.

Well, cardboard will be a lot easier to build, and to move around initially, but the first time you turn it on, it will probably turn itself into lot's of little peices flying all over your HT room!

Seriously, the AS-15 is a lot of work; helped Thomas a little with that one, but it one really sweet, wide range sub. We got the best out of it by using an inline Eq and getting it flat in the top and bottom end (the HE-15 rolls a bit prematurely in the top), then it worked quite well regarding overall integration with pretty much any crossover frequency choice, even 100 Hz.

My normal recommendation for it, depending on your mains, is between 60 and 80 Hz.

Have fun! BPD1503's are killer drivers, especially for the money. Being space limited, I picked up 1203's.

~Jon

[Bing Fung]

I'm going to build a copy of the AS-15 above, only out of cardboard!!! ROTFLOL.

:laughat: A person after my own heart :B Touch'e Ben :rofl:

Image not available


That AS-15 is one killer design, and I think that 1503 in there is going to be nice :yesnod: I was thinking of building one based on the 1203...


Jon, how are you using your 1203's? Maybe I should purchase another one to either build 2 individual AS-12 style subs, or one bigger box with both drivers (sealed). To make up for the less than 15" sub?

However I was wanting to wait until you guys finalized the Atlas's or what ever the XLB^2 ones will be named.

[Andrew Pratt]

Sounds like you're going to have one smoking sub Ben :T I'm not sure what my Tumult box weighs but I know the small 1203 box I built for George ended up bing 117 lbs all said and done and it was much smaller then what we're building

[Kyle Richardson]

I'm not doubting you Kyle

Yeah, yeah whatever..... Just kidding.
Its always great to get other people's opinions and you shouldnt hesitate to ask. Also, the nice thing about DIY is that you can pick and choose how you want YOUR sub to sound and perform (to a certain extent). So, what alignment may be great for one person may not for another so its always good to get a variety of opinions.

Also, if you have the time and patience its sometimes a good idea to build a couple different test boxes to see how it performs in them and then pick the one you like best to finish completely.

[Kyle Richardson]

Oh, I forgot to add...figure the 1503 occupying about 6-7 liters of airspace.

[Bent]

(I think I'll call mine the "BP-AS-15-03", if nobody minds).

Well guys, I'm having a tiny bit of trouble figuring the panel dimensions of the AS-15, as the resolution of the photos in the link above make it tough for me to see where the box seams are (not that I'm complaining). After doing a search on the BP-1503 and finding a link where the AS-15 was mentioned - and someone who was replying was really having a hard time grasping the fact that he was to build the box and port it to match the box volume and not for the parameters of the driver... - also made mention of some CAD drawings being available. Is there any chance that these drawings are still available for download (or purchase?).
I'd like to have a cabinet maker do my cuts and having some good drawings for him to go by would likely be a big help. (I understand that the driver cut-out as well as the cut-outs to support the 6" port will require both items ahead of time)
Oh, any reason I can't have the flared ends of the ports milled from MDF as well, or will it not hold up to that sort of work?

According to Kyle the '15 incher is now paid for and should ship tomorrow!!!

[ThomasW]

Sorry no CAD drawings ...... I literally make these things up as I'm building them. So there were no plans, there are no plans, just a couple little drawings on pieces of scrap paper.

Why are the seams important? You can see them in the pictures.

Your cabinet maker should be able to fabricate the box from the info below and additional info on the website.

From the website.

The outside dimensions of the box are 18" wide, 29" tall, 35" deep. All the walls are doubled 3/4" MDF except the front baffle, it is 3 layers of 3/4" MDF.

There are 4 routed internal braces. These are spaced as follows. The first is 4.5" back from the from the front baffle. The rest are placed every 6" thereafter. The cutouts for the routed braces are 13.5" dia. for the area directly behind the woofer and 6.5" dia. for the port.

Yes the front flare can be made from MDF. The outside diameter of the flare is 9". I'm not sure how one fabricates a rear flare out of MDF.

Think of a ported box like a empty pop bottle. You blow over the top and it makes a sound. That sound is the tuning frequency of the bottle.

In the case of a ported box, the box itself is tuned to a specific frequency (this is a function of the size of the box and the size of the port). That tuning is independent of the driver being used. Now one can fine tune a box using all the T/S parameters, but for most situations it's not necessary.

Also the pertnant T/S parameters for the BP and the HE are similar enough to be insignificant. Also since the AS-15 box was used to create Pete's ported tube sub, and there are 2 of that design in use, I know that the BP will be fine in the AS-15 box.

BP1503

Fs=26.8Hz
Qms = 7.90
Qes = 0.32
Qts = 0.30
Cms = 143.45 uM/N
Vas = 132.80 liters

HE-15

Fs: 26 Hz
Qms: 6.0
Qes: .345
Qts: .326
Vas: 106.7 L
Cms: .145 mm/N

[Andrew Pratt]

Sorry no CAD drawings ...... I literally make these things up as I'm building them

Nice to know I'm not the only one that wings it most of the time My CAD drawings are all just sketches on scraps of paper...though I did try to make some nicer plans for the Tumult box I'm building but they got trashed when we learned the wood I wanted to use wasn't wide enough so it was back to the scrap paper and pencil anyway...serves me right for planning ahead

[JonMarsh]

I started some for the AS-15 project, but don't recall finishing them (never built another one).

I'll take a look around and see what state they're in... maybe they can be updated and completed for the most part- at least, something more conrete to start with.

I'm more insterested in doing as AS-12 for my BPD1203's.


Regards,

Jon

[PiDD]

The outside dimensions of the box are 18" wide, 29" tall, 35" deep. All the walls are doubled 3/4" MDF except the front baffle, it is 3 layers of 3/4" MDF.

That is one SERIOUS box!

[Andrew Pratt]

Go Big or Go Home The big advantage of DIY is that you don't have to compromise on size and weight like the comercial guys do.

[ThomasW]

That is one SERIOUS box!

Yeap, around 300+lbs including the driver.......... :E

[Bent]

well that means that any chance of theft is quite unlikely!

[ThomasW]

Yeap, unless it's a smash and grab using a fork lift :wink:

I need to add that although the AS-15 uses 6" flares, the ID of the PVC port used is 5.75". If you use a port material with a 6" ID, the port will need to be longer.

Also you don't need to exactly copy the design of the interior bracing. My 'artistic' side sometime likes to play with stuff. So the bracing and it's design was as much as study in something visually interesting, as it was functional concept.

[Bent]

Yup, I get the part about the port being 5-3/4 inches ID.
Part of what makes this sub special is the massive size port on it - problem will be to just stop my kids from putting things into it... Maybe a 22hz tone burst when they get close to it will stop them, LOL

[Bing Fung]

I'm more insterested in doing as AS-12 for my BPD1203's.

Jon

Yes Jon, I'm interested in you doing a AS-12 for the BP1203 too :W :T

Jon, what is the best ported box size (Internal volume) for the BP 1203?

I try modeling the sub in Unibox and WinISD pro, but it always rolls or dips off at 40 hz. I need to see what you guys state is a good model for this driver, so I can understand how it should be modeled. 70 liters with about 21 hz tune?

I modeled the 1503 and noticed the same thing in Unbox and WinISD Pro :scratchhead:

[Bent]

I modeled the 1503 and noticed the same thing in Unbox and

those were my results too, if doing it via the T/S parameters, but when I used a HUGEer box and ported it to suit a much lower frequency it seemed that all the rules went out the window...

[Bing Fung]

Glad to know it's not just me that feels confused when I model these drivers :scratchhead:

[Kyle Richardson]

Yep, they model up funny in the sims, but just drop them in a bigger box than the programs recommend and as Bing found out they perform admirably.

[ThomasW]

Bing

The Unibox plot you posted for your box with the 1203, looks just what I'd expect.....

I don't have the original AS-15 sim plot to post. I lost the LspCAD data files years ago when my PC crashed and haven't needed them since.

The plot had the stereotypic 'saddle' with it's peak around the ~18Hz tuning frequency, and a dip above that. Room gain fills in the dip.

For a real world example of what happens, look at the measured data from the in-room AS-15 testing and the applied EQ.

[Steve Goff]

Thomas,
What would you use for EQ these days?

[ThomasW]

The big IB has a Symetrix 551, the little IB has a Behringer DSP1124P.

When I use any of the 'portable' subs I use a Behringer with them. It's handy since I keep can individual settings for each sub, and toggle back and forth between them as needed needed.

[Steve Goff]

I use the Rane PE17, which is similar to the 551, but lets you use all five EQs in the sub region. (Am I correct that the 551 only lets you use three in the same area?)

Do you think there is a difference in sound between the analog and digital EQs? I ask in part because I'm thinking about a speaker with woofers like the TC2+ that can go fairly high with a separate amp and EQ up to about a 250 to 300Hz crossover point.

[ThomasW]

The 551 has 5 bands that can be used anywhere, lowest frequency setting is 10Hz.

Nousaine uses a 551, he compounds two filters at 10Hz to provide boost down to 8Hz.

Don't ask me why .......... :B

I've never used EQ for anything other than subs so don't know. There's no audible difference between the Symetrix and the Behringer EQing the IB subs. I wouldn't use low buck digitals for higher frequencies.

[Bing Fung]

Kyle, The sub performs beautifully after EQ'ing it :T

However based on simulations, I would have never picked the 1203 as a candidate, just because of the steady roll off below 40hz. Thats what confuses me. I know a person can expect about a +10dB room gain on the lower end of the response. It's that assumption of the added gain that confuses me, and how to model that in to a driver that starts rolling off at 40 hz. How can it be determined it will work well untill actual measurements?

I just I always thought you want the flatest response you can get from 100hz to 20Hz, independant of room gain, yet all these high excursion drivers break all those rules, yet still work fine. I find it tough to even know what is a good response then if nothing is flat to 20hz... How do I know it will work ou tin the end?

Thomas, yep, that AS-15 looks like the BP1203

What is the 1000 Watt line in Unibox, and why does that seem like the response we are looking for, but actual driver response rolls off before that?

[ThomasW]

LspCAD let's you model room gain if you know all the acoustical characteristics of the room. It's a pain to do.

Drivers like the BP with their high Fs start rolling off pretty fast and high. But using a port or LT circuit allows these drivers to perform very well in spite of what the sims show. The reality is that the performance will be very close to that shown in the UniBox 1000 watt SPL plot, even if the inout power is lower.

The 'trick' to getting these to work right is choosing the correct port tuning frequency and knowing that room gain will fill-in the rest.

I find it tough to even know what is a good response then if nothing is flat to 20hz... How do I know it will work out in the end?

You trust the in the force .. and ask here for advise..... :wink:

[Bing Fung]

You trust the in the force .. and ask here for advise..... :wink:

:laughat: It was a leap of faith, that worked out better than expected :T

But Master, when will I too know and feel the force? :W

[Kyle Richardson]

I find it tough to even know what is a good response then if nothing is flat to 20hz... How do I know it will work ou tin the end?

As Thomas stated, some programs will allow you to calculate room gain into the simulation.

The key phrase here is "computer SIMULATION". They give you a good estimate of what it MIGHT perform like but you never know exactly how it will work until you build it and test it in YOUR room. Thats part of the DIY process....build, test, alter, test, alter, etc. Some people just build and place it and call it good where others will test and alter the design multiple times until they get it exactly the way they want. Ultimately it comes down to how you want it!

Some people design their subs with the roll off in place so room gain will result in a flat response down low while others will design so that it sims flat but room gain will actually cause a rise in the low frequencies for the extra sensory impact. How you design it is up to you since you're the one building it and you're the one using it.

I like to tell people that if they have the time to build some test boxes first. Just whip one out quickly and dont finish it or anything and that way they can experiment with different tunings without worrying about ruining their final box. Once they have the design they want then they can take the time to build their final box taking care so they can finish it nicely.

[Kyle Richardson]

It was a leap of faith

Oh, and sometimes that works just as well as anything else

[Bent]

Well guys, it's on it's way.
Status: In Transit

Shipped to: STEINBACH, MB, CA
Shipped or Billed on: 25 Oct 2004



Tracking Number: 1Z Y58 921 68 xxx xxx x
Service Type: STANDARD
Weight: 55.00 Lbs

It's still scheduled to arrive on the 1st.

now I need about another 100 bucks for the ADA 1200 amp...

8)

[Bing Fung]

Kyle, it would seem the case that real world tests is "Proof in the pudding" However it seems also it takes experience to recognise a diamond in the rough

[Kyle Richardson]

Bing, somtimes that is the case especially with some of the higher perfomance drivers.

[Bent]

Well, it arrived in WPG tonight, it is awaiting clearance but UPS gave me the bad new$ - $90.45 in brokerage and tax owing upon delivery Monday. Ouch.

total landed cost (including me getting raped on the exchange rate at the post office) is almost 495 dollars CDN.

It's a good thing Adires' 1200 watt plate amp isn't available just yet - cause I can't afford it for at least a couple of weeks. :cry:

But wow, I'm still pumped about a big new subwoofer!!! :T

B.T.W, Kyle, thanks a bunch -I'd never have gotten the 1503 if you weren't willing to make an exception to your shipping rules - but there was nowhere else I could go for one. I'm going to try to do the best job I can in building this behemoth so I can post some pics and show everyone.

[Kyle Richardson]

No problem about shipping to Canada. Actually, because of you and Bing I'm now going to ship drivers to Canada to whomever wants them but I still wont ship enclosures.

Oh, and sorry to hear about the brokerage and tad fees. Ouch.

[Bent]

I checked on UPS's website, and found this!!!
WTF? to winnipeg, (45 miles away), then back to Minneapolis???
(Did Prince want to see my driver first, LOL).

looks like I'm going to have to wauit just a bit more...


:cry:

(oh, wait, maybe it was just the shipping docs that made it to WPG...)

[Andrew Pratt]

Ben that's typical...I think the system automatically adds in the winnipeg location once the brokerage process gets started...at least I've noticed that in past as well on other items I'm imported.

[Bent]

Well, it's back in WPG again - looks like scheduled delivery is tommorow. :tup

[Andrew Pratt]

Remember to bring your back brace when you go to get it...and always lift with your knee's