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Those are charts of projected plot-not measurements. Ill look harder


Heres the measurement from my mini devastator loaded with 18ds115. The mini has a 20hz port tune.


Here's the close mic sweep.
Orange is natural response, Blue is 20hz 2nd order HPF.
Need to repost that graph with correct scaling, but you get the idea.
Chris
 

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You are correct sir. I thought I was being fair, guess not.
i kind of get where the OP was going..Im seeing alot of these Lavoce 18s and these B&C 18s..ive always been curious how much of an upgrade one of them would be over the PA-460....
 

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i kind of get where the OP was going..Im seeing alot of these Lavoce 18s and these B&C 18s..ive always been curious how much of an upgrade one of them would be over the PA-460....

In general, not one that works. If the enclosure was designed for the PA, the high end drivers are going to have absolutely ridiculous port velocities.

Now if the enclosure was designed for the high end driver, and the PA was substituted to reduce cost, then there will be a significant increase in performance. However, even more performance can be achieved for the money and amplifier power by just adding more PA’s.

Chris
 

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I've always been a big believer in buying better drivers right from the start. Ive never been a "buy a bunch of cheaper drivers to equal one good one" type of guy.
I fully understand why people do it,I personally would just save up a bit longer and get something better.... But that's just me.... And I also run my stuff hard, so there's that... Lol
Ditto.
Things are a bit different if you run things hard and / or have a limited space to work with.
 

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Ditto.

Things are a bit different if you run things hard and / or have a limited space to work with.

Agreed, I’m space limited, and prefer drivers that I can’t damage within reason. Since I tend to push them by nature.
I don’t pretend they’re cost effective though, I’d rather not think about what I’ve spent on them.

Chris
 

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If your are looking for simple way to weed out use Le/Res any keep it under 1ms. If you go to DB and run down the list all the drivers under 1ms are considered good performers and the lower you get the higher up the food chain they are considered.


I can't say how far apart you need to be to notice but I went from drivers with 1.1ms to drivers at .5ms and the difference is audible above moderate levels.
I disagree with this.
It is never as simple as looking at a single point spec. Ever.
Doesn't matter if it is Xmax, power handling, sensitivity, Qts, etc...
Even normalized Le/Res is not a good indicator of the functional inductance of a driver and any variation or offset as the coil moves in the gap. It has to be considered with many other factors such as moving mass and motor strength. The easiest way to compare inductance of drivers is by looking at the impedance curve shape above the highest resonance and the frequency response shape. Even this is greatly simplified.

Some drivers with a lower Le/Res value exhibit greater inductance effects than those with a higher value.
 

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If you compare a single B&C 21 vs a single PA-460, the B&C obviously will win in every regard but price.

But if you compare the price-equivalence of the two, you can buy ~13 PA-460's for the price of 1 IPAL-21, and if you compare those I'm pretty sure the array of 460's will have lower distortion, higher power handling/long-term output, and higher SPL. (Haven't modeled it.)

There may be some box configuration where the IPAL magically out-does it in the low bass or something, but generally that holds true...

The key here is IF you have the SPACE for 13 18's! ;)

For people who have more money than space, an SI-24 or RF-19 or B&C 21 might be the ideal purchase.

If you have lots of money and space, the better drivers will still be better.

Only if you have lots of space and little money (or you are aiming for max-value on a budget), then multiples of the cheaper drivers is the way to go!

A single PA-460 is basically ramen-noodle budget level, everyone should be able to afford at least 1 (and if you can't then you really probably shouldn't be building a HT at-all nor holding an Galaxy/iPhone 9000 for that matter.)
 

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Ignoring fancy box-types and room-influences.

Low frequencies are almost entirely displacement-limited.
Displacement being total-cone-area x excursion.

You need to use just-enough cones and just-enough watts to propel it for your desired listening-SPL/distance.

Mid-bass is a bit different, it is mostly total-cone-area and power-handling / driver efficiency and a few other things (moving-mass etc.)

BL and LE are great too!

Obviously as power levels increase, any extra cooling or excursion can be very beneficial, if not life-saving, especially in terms of keeping things SAFE.

With enough cones and space and amplification you can achieve any objective with any driver (within reason).
32 Sony Xplods vs 1 SI-24/B&C-21 etc... :D
(*as long as the box leaks aren't too extreme and the box is standard +3/4" & braced...)

^^^all of the above is greatly over-simplified of course. But isn't far off...

Now obviously 9000 Bose modules will never equal anything DIY, there ARE limits here! :D
 

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With enough cones and space and amplification you can achieve any objective with any driver (within reason).
32 Sony Xplods vs 1 SI-24/B&C-21 etc... :D

...except the 32 Sonys could handle 3200W (100W per) literally all day, while giving a significantly higher vd and SPL and significantly lower distortion, port velocity, and power compression. So there's that...:)


However the Sonys would take up about 4x the volume in your room. Hoffman's iron law and all that.:(
 
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