Best Sub Driver for small enclosures (1 Viewer)

[Ville Javanainen]

Thomas,
I meant fast bass, like doublebass etc
(I don't know is the right word in english for what i mean )
I'm 90% sure of buying a 1203, when/if they arrive in Europe..
About the box, I don't want to build a cube, more like a REL Storm 3 etc style, so it wont take as much floorspace.
Any suggestions?

 

[ThomasW]

I believe the correct term is quick 'transient response'
The box can be pretty much any shape you want. Sealed are more flexible than ported. With ported designs you're stuck with the length of the port dominating one of the dimensions.

 

[Ville Javanainen]

How about the dimensions of the box? I dont have any simulation software right now installed on computer, so what kind of Qtc would give me tight, low bass? The max size of box should be 50 litres, but the smaller the better

 

[Jack Gilvey]

If you look back at the thread, you'll see that 48 liters was the recommended size to start off with. The actual dimensions are up to you. Without properly eq-ing, though (as was discussed), you will have no low end to speak of.

Install some software, and you can play with the designs and various sizes.

 

[Ville Javanainen]

I found a review of 1503, check it out:
http://www.termpro.com/cgi-bin/ubb/u...c&f=8&t=008349
Hmm.. I don't know if I should start to build the box yet, because I don't know when the Blueprints will be available in Europe and will be the price of 1203..

 

[Ville Javanainen]

Damn.. It looks like i'm not gonna have BP 1203 this christmas, I emailed to BPD, here's the answer...:

Sorry, no new news. We have yet to have an opening order from two UK based

dealers that decided to distribute them. Most people appear to be turned

off by the shipping costs (due to size and weight) nor do they want to order

a pallets worth for freight shipping.

Sorry,

Pat

 

[Ville Javanainen]

How should the 1203 be "broken-in"? (I'm NOT sure if that is the right word.. ) Or how should any new drivers be "broken-in"? Will the t/s parameters change?

 

[Jack Gilvey]

Ville, just using them will break them in ok, although you can run some low-level (!) low-frequency tones to do it a bit quicker. Thomas will know better, but I don't think most change very drastically, maybe a lowering of the Fs when the suspension loosens up.

 

[ThomasW]

Just build the cabinet and play it. The Fs will lower slightly as the tensions between the glued components relax.

 

[Ville Javanainen]

I was just simulating with WinISD an when the box is 48 litres sealed, it has a 0.40 QTC! Shouldn't the QTC be bigger?

The -6b point is at about 46hz.

 

[ThomasW]

it has a 0.40 QTC! Shouldn't the QTC be bigger?

Do you mean higher? If so then no.....
Jon, who's already posted in this thread the all required info for this design, has 40yrs of experience designing speakers. As a matter of fact he just won 1st place in the CLIO-Win design contest For his X-1 SLAMM klones. The article hasn't been uploaded to the clio site yet.
So knock yourself out playing with sims, or trust Jon's advice. He hasn't steered me wrong in the 35yrs we've been co-designing loudspeakers.

 

[Jack Gilvey]

I was just simulating with WinISD an when the box is 48 litres sealed, it has a 0.40 QTC! Shouldn't the QTC be bigger?

Did you read any parts of the thread dealing with the design Jon proposed? EQ to lower the f3 is intrinsic to the design, and is best applied beginning with a low Qtc. The "starting" f3 in 48L is above 80Hz.

 

[Ville Javanainen]

I've received few photos from Pat:
Link Removed
BTW, will 1203 work fine in 40L sealed box? The Qtc would be 0.42
Happy Holidays to Everyone!

 

[Jon Hancock]

In practice, the difference between a Qtc of 0.42 and 0.40 is of little consequence. If you use the smaller enclosure, you can still get this system to work fine- and as long as you stay at or below a Qtc of 0.5, you won't need to use a Linkwitz transform, - just a shelving equalization will do.

However, look at the simulations of the curves, for constant power input. As you make the box smaller, you raise the Fb, and raise the Qtc, and below Fb, the response is lowered, because you have a sharper knee in the response. (from the higher Q). The drawback to this is that you will need more amplifier power and more LF equalization to produce the same acoustical output at frequencies below the box Fb. Running a Qtc of 0.4 produces a response similar to an IB; for this driver, with ideal room placement you could get fairly reasonable response to 40; for the deep bass, you need the EQ. Also, don't forget that becuase of the high voice coil inductance of this driver, the response above 70-80 will have some natural roll off, so unless you plan equalizing it flat before your electronic crossover (we've done that with Stryke drivers as well, using the BFD), you'll probably want to use a 60-75 Hz crossover. This is a good crossover point anyway, because it seems to be the highest Xover point in my expereience that doesn't start to localize the sound of the sub. I.E., if you use 100 Hz, since the filter isn't "brick wall", there's too much stuff coming out of the sub above 100 Hz for the position to not be determined.

Best regards,

Jon

 

[Brian Bunge]

Jon,

I'd like to ask you a question concerning the 1803. On the Blueprint website they mention that the simulations of the 1803 with an LT Circuit don't look very good. I'm a little confused about this and was wondering what your take on this would be. Would I be better off just adding low end EQ with my BFD? I'm looking at the 1803 in about 5ft^3 of airspace after adding stuffing.

Thanks,

Brian

 

[Ville Javanainen]

Thanks for answer Jon!

I'm planning to cross it on 80hz, because I propably buy Denon AVR-3802 av-receiver and keep all the speakers small, so it will cross them at 80hz on music AND movies...

It would be quite nice if the box would be just 30L sealed, so it would take much room at all.. 'cos my room is so little..

But theres nothing new news about the retailer in Europe for BPD..

How much watts rms can 1203 really handle?

 

[Jack Gilvey]

Try it in 30 liters and see how it works out, that's the best way I say, experiment. It will take 1000 watts.

 

[Ville Javanainen]

I e-mailed to Pat about the European retailer and here's the answer..

Blueprint was recently sold and is "moving" to Chicago. Bill (the new owner) will be taking care of the European

distribution as well (I have forwarded him all of the information). In the

meantime (until he gets the site back up with all the 02 application data as

well as the information for the new 01 series with over 16mm of Xmax) I will

continue to answer questions regarding the current product line up.

Cheers,

Pat

 

[Anthony_Gomez]

how sad:frowning:
Must have been too hard for Pat to run it as a one man show....or someone offered him a good deal on the company! I hope the quality does not suffer. I love my BPD's=)