Hmm, found it has a 5 ohm nominal impedance, so in parallel it would need to drive a 2.5 ohm load, which at a glance I seriously doubt and by the same token have to wonder if it can handle 10 ohms.
Impressive piece of furniture architecture! Regardless, seems best to ask Linn since dealing with onboard electronics.......
Eff. Vs Sens.
Impressive piece of furniture architecture! Regardless, seems best to ask Linn since dealing with onboard electronics.......
Eff. Vs Sens.
Does this mean I would have half the presently available power? So I need a bigger amp?
Sorry, just noticed your post. I believe it's a negative impedance amp to begin with. So I'm thinking over all spl gain.
Sorry, just noticed your post. I believe it's a negative impedance amp to begin with. So I'm thinking over all spl gain.
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Btw, efficiency and sensitivity is not the same thing. Sensitivity figure is typically averaged some 200-2000Hz range or so.
So one cannot say anything about sub/bass efficiency out of typical sensitivity numbers given by thiele small parameters.
Overall bass efficiency and sensitivity is pretty much depending on enclosure type / size. Same driver in sealed enclosure might be 0.2% efficient but when using large horn, efficiency can be as high as 20% or even more!
I had some JBL 2206H's, which has quite good sensitivity number (ofcourse these are pretty efficient drivers too when used properly). I tested these in bass reflex and tapped horn enclosures. Then I swapped it to a heavy coned Impact 12" car subwoofer having much smaller sensitivity number of 88dB, but it was actually more sensitive @ bass frequencies!
So one cannot say anything about sub/bass efficiency out of typical sensitivity numbers given by thiele small parameters.
Overall bass efficiency and sensitivity is pretty much depending on enclosure type / size. Same driver in sealed enclosure might be 0.2% efficient but when using large horn, efficiency can be as high as 20% or even more!
I had some JBL 2206H's, which has quite good sensitivity number (ofcourse these are pretty efficient drivers too when used properly). I tested these in bass reflex and tapped horn enclosures. Then I swapped it to a heavy coned Impact 12" car subwoofer having much smaller sensitivity number of 88dB, but it was actually more sensitive @ bass frequencies!
See if the amp can drive half the load impedance. Probably not because it was built to do what it is doing and not twice the current. You would need an amp that can deliver twice the current because it’s half the load or use another of the same amp.
Since you want more output, we can assume the amp is being driven as hard as it is capable, so would not suggest a lower impedance load.
To increase low frequency efficiency by 3dB would also require doubling the box size when adding another pair of drivers.
The DAISY OUTPUT from the AV 5150 provides a filtered output which could be used to drive an additional amp powering your additional speakers in additional boxes.
what is your opinion on post #18, 19? I could still add an additional amp. Space is an issue. So is output. 6db would do it. I'm a bit intrigued by the potential increase in over all performance with this set up in terms of the decrease in distortion. Could I end up with a cleaner presentation?
Remember if each of the two drivers is driven by different amps you don’t get the additional 3db from halving the load impedance. You only get the 3db from having two drivers doing the same thing.
depending on wavelenght/distance you actually get more.
it is like the gain you get from a near wall (+3dB). you halve the space one driver has to take care of.
Seems to me like you're wanting to chuck more drivers into the same enclosure. You will get more SPL, but not at the lowest frequencies, most likely you'll see the biggest effects above 30-40Hz.
If you make two indentical subs then you get +6db at the expense of adding +3db worth of power, so it's a good solution IMO.
If you make two indentical subs then you get +6db at the expense of adding +3db worth of power, so it's a good solution IMO.
Yes, same idea as opposing woofers for the same reasons, just isobaric. Why would spl not increase at the bottom? This is an often used configuration to improve performance albeit not isobarically. But how does that change it?
As GM wrote, doubling up drivers, i.e. [2x displacement = + 3 dB] +[2x power = +3 dB] = + 6 dB total "available", but only if the enclosure volume is also doubled.
If double the drivers are put into the same size enclosure, the low frequency displacement won't double unless more power than +3dB is used, as the air spring resists the additional driver's low frequency displacement.
The example above illustrates what KaffiMann wrote in post #32.
Art
Just to be clear: You have a box that contains two drivers mounted dual opposed, and want to add another driver isobarically to each of the existing?
You will not gain anything from this, what isobaric effectively does is sacrifice drivers xmax to emulate a bigger enclosure. You gain nothing but become able to make a smaller box at the expense of more drivers and more added power.
Here is an example of 15" drivers where I drew the line at 5mm/40Hz.
If you have a fixed volume, nothing else changes but the box is effectively nearly doubled in size at the expense of twice the power consumption and twice the drivers.
36V/8Ohms = 4.5A
4.5A*8Ohms = 162VA
18V/4Ohms = 4.5A
4.5A*4Ohms = 81VA
If you decide to make another box, giving you two identical subs, you will gain +6dB from drivers surface area and xmax at the expense of +3dB power.
Okay, there's clearly a confusion here. The Linn 5150 is an isobaric vented subwoofer with a pair of 12" drivers mounted in a clamshell config facing downward. I want to cut the tops and add another pair facing upward. This is what GM responded to in post #18.
Then you'll get a result about equal to Weltersys' previous post.
You're using the same volume, it's the same as adding another driver.
I don't understand why people use Isobaric, it's a waste IMO.
If you absolutely must, use a single bigger and badder driver in a too small closed box and force feed it gobs of power. More or less the same end result as adding a ton of drivers that merely flap about and consume about the same amount of power. I'm not an advocate for either solution, but whatever floats your boat.
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The point was that usually you'll end up in much the same place regardless in terms of cost of drivers and power consumption, one big higher xmax driver merely helps to lower build complexity.
You're using the same volume, it's the same as adding another driver.
I don't understand why people use Isobaric, it's a waste IMO.
If you absolutely must, use a single bigger and badder driver in a too small closed box and force feed it gobs of power. More or less the same end result as adding a ton of drivers that merely flap about and consume about the same amount of power. I'm not an advocate for either solution, but whatever floats your boat.
Edit:
The point was that usually you'll end up in much the same place regardless in terms of cost of drivers and power consumption, one big higher xmax driver merely helps to lower build complexity.
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There is a basic issue here - there are 3 aspects of a bass speaker that are mutually "incompatible":
1) deep bass extension
2) high efficiency
3) small size
You cannot benefit one without taking a hit with at least one of the others (assuming your drivers aren't rubbish to start with of course!) So if you want more efficiency with the same frequency response you are pretty much forced to go larger. For instance ported enclosures trade efficiency for the other properties, which is just the other side of the coin.
This is a simplistic rule of thumb, but generally a useful guide. There's going to be some milage in speaker placement and room dimensions of course as the acoustics/resonances of the room have some effect.
Good efficiency is going to push in the direction of larger driver, larger box, basically - or put another way the more efficienct 12" drivers will only be able to drive a large box well.
1) deep bass extension
2) high efficiency
3) small size
You cannot benefit one without taking a hit with at least one of the others (assuming your drivers aren't rubbish to start with of course!) So if you want more efficiency with the same frequency response you are pretty much forced to go larger. For instance ported enclosures trade efficiency for the other properties, which is just the other side of the coin.
This is a simplistic rule of thumb, but generally a useful guide. There's going to be some milage in speaker placement and room dimensions of course as the acoustics/resonances of the room have some effect.
Good efficiency is going to push in the direction of larger driver, larger box, basically - or put another way the more efficienct 12" drivers will only be able to drive a large box well.
Pete,
The "clamshell" isobaric loading halves the Vas of the drivers used, allowing the cabinet volume to be reduced while retaining the same F3, but using double the power to achieve it- classic Hofmann's iron law: low, loud, efficient, pick two.
Like the sealed example in #34, a similar increase in upper response, with LF output at Fb (probably near 15Hz) remaining the same as it presently is will happen if you add another pair facing upward, and provide the same voltage to both pairs of drivers.
You would also want to build a plenum above the upward pair to provide equivalent loading as the lower pair has.
If you like disco era bass, that increased upper bass response may be just what you want, if you want more around Fb, you'll need to build a duplicate cabinet and power it up.
Art
I can't find something online showing the interior of the 5150. However
- You're not going to get more volume driving more woofers from the same amp. Amplifier losses are proportional to current squared IIRC, so very low impedances actually decrease the peak clipping power.
- I don't understand why you're cutting. Are you trying to shove more drivers into the same cabinet? That will not work, it will screw up the alignment.
@KaffiMann has a point, isobarik doesn't get you anything that a different driver might achieve. Well, there can be some distortion reduction due to motion symmetry, at the expense of taking up volume with a second driver.
--> Really lo these many years on, if you want more output without taking up much more space, you should get a new subwoofer with a humongous amplifier.
Since the time of that Linn, loudspeaker design and subwoofers especially has evolved a lot. Nobody's "broken" Hofmann's Iron Law, however what can be achieved within those confines has increased drastically. It's rather like how SUVs couldn't handle or corner worth a darn, but now you can get hyper-SUVs like the Lamborghini which have amazing handling and cornering for their size, based on spending a ton money on tires and wheels and suspension.