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Author Topic: BC218  (Read 25871 times)

Ivan Beaver

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Re: BC218
« Reply #40 on: August 25, 2015, 07:54:41 am »

Ivan, when you say 4 cabinets do you mean 4 of the single boxes (2x18) or 4 "sets" of paired cabinets?
I was talking about 4 single cabinets.

The design of the BC218 was to be used with a "mating cabinet"-but can be used by itself.

So 2 cabinets is more than "twice one"-if that makes any sense.

It is "looking for" the loading of the second cabinet to get full performance.

But they work very well in singles, just better in doubles.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Ivan Beaver

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Re: BC218
« Reply #41 on: August 25, 2015, 07:59:18 am »

It could be. If you have 16 double 18 vented subs,  like electrovoice, they are 96 db efficient. They will gain around 12 db in eff and around 15 from power increase. They have around 3000watts and around 133 db continous. So all in all they will have around 138-140 db at 10 meters

People aren't rational. We're not thinking machines, we're - we're feeling machines that happen to think. Peter Watts
You HAVE to look at more than just a simple SPL number.

You HAVE to consider the freq at which that SPL number was being referenced to.

Most subs have nowhere near flat response, so the SPL number (continuous or peak) could be at any freq.

Looking at the calibrated UNPROCESSED freq response (processed hides much of the useful information) gives a MUCH better idea of what is really going on.

Some companies are very good with their specs, and some are VERY deceiving with their specs-even with the TOP manufacturers.

You HAVE to make sure you are comparing the same things.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

radulescu_paul_mircea

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Re: BC218
« Reply #42 on: August 25, 2015, 08:33:59 am »

I was talking about 4 single cabinets.

The design of the BC218 was to be used with a "mating cabinet"-but can be used by itself.

So 2 cabinets is more than "twice one"-if that makes any sense.

It is "looking for" the loading of the second cabinet to get full performance.

But they work very well in singles, just better in doubles.
So the measurements from the specs sheet are made using a single or using a pair and then put the specs from only one?

People aren't rational. We're not thinking machines, we're - we're feeling machines that happen to think. Peter Watts

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radulescu_paul_mircea

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Re: BC218
« Reply #43 on: August 25, 2015, 08:37:04 am »

You HAVE to look at more than just a simple SPL number.

You HAVE to consider the freq at which that SPL number was being referenced to.

Most subs have nowhere near flat response, so the SPL number (continuous or peak) could be at any freq.

Looking at the calibrated UNPROCESSED freq response (processed hides much of the useful information) gives a MUCH better idea of what is really going on.

Some companies are very good with their specs, and some are VERY deceiving with their specs-even with the TOP manufacturers.

You HAVE to make sure you are comparing the same things.
I was refering to EV because I've measured them with a calibrated mic two years ago, and they were at an average of 113 db at 10 meters with 20% distortion at 37 hz

People aren't rational. We're not thinking machines, we're - we're feeling machines that happen to think. Peter Watts

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radulescu_paul_mircea

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Re: BC218
« Reply #44 on: August 25, 2015, 09:13:44 am »

This is what happens when you compare the "simple numbers".

You HAVE to look at not just the SPL numbers but ALSO the freq response.

Yes the J1 has a HUGE amount of bass output (one of my favorite cabinets), but it does not go as low the BC415.

Depending on styles of music, you could need 4 or more BC415/BC218s to "keep up" with J1.  On other styles it is more like 2:1.

Yes the Caleb (J5) has 12x 18" woofers, but it is VERY different than the J1 in several ways.

Because we were not interested in the Caleb going real low, we used lighter weight (than the J1 or BC218) 18" woofers, that gave us more output where we really needed it.

Also they are loaded on a much shorter horn than the J1.

The idea for the J1 was to have a single full range cabinet that could be used for most normal types of music without a sub.

The Caleb would probably always be used with subs in a larger situation-so it did not need to go as low.

Off hand I don't know low low the Caleb maintains its pattern control-but we (not me) have done the measurements and will be getting the data into our DIRECT modeling program soon.

But due to the large mouth, it is much lower than other 40* cabinets.
Ha!
Whenever I think at J1 and J5 i feel like a child looking at a stack of candy :))
Can't wait to work with this products!!
Thanks for the answers

People aren't rational. We're not thinking machines, we're - we're feeling machines that happen to think. Peter Watts

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radulescu_paul_mircea

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Re: BC218
« Reply #45 on: August 25, 2015, 09:16:28 am »

No, I do not have two of these stacks.   That would just cause lobing in the horizontal which I have no need for.   I chose the 5000HD's so that I can get enough "peak room".   Peak, RMS, and Thermal Limiters are set accordingly.
So, now back to you ,sir.
I was waiting for you to tell us what mains are you using...

People aren't rational. We're not thinking machines, we're - we're feeling machines that happen to think. Peter Watts

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radulescu_paul_mircea

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Re: BC218
« Reply #46 on: August 25, 2015, 09:38:22 am »

The TH221 was designed (like it name-the cinimonster) to a high output sub that gets you solid down to 20Hz -without room gain.

With room gain-it is even more.

It does not have as much output as some of our other large subs, but it goes lower.

With bass extension you HAVE to trade something.

It is being used in a number of high end theaters.

The IPAL is an interesting driver.  Just because it "appears" to be better, does not mean it will actually WORK better.

In some designs it might, but Tom has modeled it several times and the big advantage of the IPAL (motor strength) is actually to much for our horn designs. 

So we can actually get better performance with a "weaker" driver-at a lower cost.

So once again-it is not what is "better", but what is "better for a specific usage".

We do this in a number of our designs.  Sometimes the "lessor" driver ends up working better.

That is the reason you model-measure etc, and don't just "stick popular drivers" in cabinets.

It is all about how the different parts of the overall cabinet work together.  Not only the drivers themselves, but also the cabinet, crossover etc.
Yes,indeed you are building real subwoofers fo a real market and it is no need to overkill where it is with no use.
As I was talking on another forum about the posibility of using the M-force driver in your designs, people had given me good arguments on "why NOT to use them"
That driver (and also the I-Pal ) need specific tweaks and designs to work properly, they are (very) expensive and they could be used only in places where cost is no object. Like the Tingpen rotary.
Yes,it would be fascinating to just see what is possible. You could use 20 of them, in 10 VERY VERY large horns and try to sim a real tornado or a rocket, but otherwise, I don't know.
 What is your oppinion on that type of driver and tech.?
For me, powersoft, pkn and speakerPower represents in amp world the same as DSL in speaker world. Except DSL are trying to make a revolution,not evolution ;)

People aren't rational. We're not thinking machines, we're - we're feeling machines that happen to think. Peter Watts

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David Sturzenbecher

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Re: BC218
« Reply #47 on: August 25, 2015, 10:36:42 am »

So, now back to you ,sir.
I was waiting for you to tell us what mains are you using...

People aren't rational. We're not thinking machines, we're - we're feeling machines that happen to think. Peter Watts

No need to derail a perfectly good Danley thread right :) ? Sometimes it's nice when threads stay germane to the topic at hand.  There should be some articles coming out soon.
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radulescu_paul_mircea

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Re: BC218
« Reply #48 on: August 25, 2015, 10:43:33 am »

No need to derail a perfectly good Danley thread right :) ? Sometimes it's nice when threads stay germane to the topic at hand.  There should be some articles coming out soon.
Yes indeed!
Some measurements of those beautiful monsters? :D

People aren't rational. We're not thinking machines, we're - we're feeling machines that happen to think. Peter Watts

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Ivan Beaver

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Re: BC218
« Reply #49 on: August 25, 2015, 12:47:46 pm »

So the measurements from the specs sheet are made using a single or using a pair and then put the specs from only one?

People aren't rational. We're not thinking machines, we're - we're feeling machines that happen to think. Peter Watts
The "simple numbers" are for a single cabinet (NOT the dual pair)

However the spec sheet shows the freq response of both single and duals in both of the normal configurations (standing up and laying down).

As you will notice, the response is different for the different configurations.

Hence the reason for seeing the ACTUAL MEASURED response-and not a "simple number".
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!
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