I have a pair of Acoustic Research bookshelf speakers with voice coil rub so am going to replace the drivers using speakers from a set of Definitive Technology 5.1 speakers. However, the AR cabs are sealed and twice the size of the DT satellites. The satellites also have a single passive radiator the same size as their driver in each. I’d like to add the PR to the larger cabinets. Most research that I’ve done shows PRs being twice the size of the driver, so should I add 2 to each cabinet?
I haven’t checked the specs in the speakers, but where’s the fun in replacing with the same on this page? I like the idea of PR or 2 (which is different than a port or vent) and since I don’t have any measuring equipment or experience yet, this will just be by ear. I’ll compare the new builds to these pictures as reference. I’ll also try without the sub for full signal test.
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It functions as a vent, but brings an extra, unwanted, resonance. A PR is typically used when the low tuned vent of a small box becomes so large as to be unmanagable.
dave
You might be able to get replacement cones for the ARs, if they're a popular classic model. I've re-surrounded a woofer and we both survived, so it's not that difficult.
Nah, unless I can find them for free that is. Everything I’ve posted so far has come free out of the electronics recycling g bins and reuse it centre here in Banff. I literally just picked up a Klipsch 5.1 system today, the .1 being a powered Pioneer subwoofer. I like the idea of Frankensteining a set of speakers out of free parts. I’ve got an old set of BOSE 501s that needed the woofers reconed, but I’m just going to replace them with clear woofers out of some other pair of speakers and put LED lights behind them so they flash while they play.
As I understand them, PR are similar but better in small speakers that don’t have room for a vent. What I’m trying to find out is, would 2 PRs be better? As most articles talk about the PR having twice as much surface area as the driver. Plus the DT drivers have a nifty looking dust cover, literally looks like the bolts sticking out of Frankenstein’s neck, so I’ll be using those.
I’ll probably clamp the PRs down using bicycle sprockets or something industrial looking.
I’ll probably clamp the PRs down using bicycle sprockets or something industrial looking.
Take care:
If the box is a smaller one doubling the surface of the PR means doubling the mass you have to attach to the PR drivers.
Tuning low then becomes difficult - the PRs can sag and rub if you use real drivers from other boxes.
Try some calculator for passive radiator mass before doubling the surface.
If the box is a smaller one doubling the surface of the PR means doubling the mass you have to attach to the PR drivers.
Tuning low then becomes difficult - the PRs can sag and rub if you use real drivers from other boxes.
Try some calculator for passive radiator mass before doubling the surface.
These are my speakers. The AR cabinet is larger than the single driver satellite speaker. I’m going to scavenge the centre channel speaker as it has 2 drivers and 2 PRs but the cab they’re coming out of is smaller and the rest of the satellites are half the size with a PR firing up. So I’ll be putting at least 1 PR in each of the larger AR cabs with the scavenged driver.
So first I’ll try it without the PR, just the driver, then I’ll add 1 PR to just the left speaker, then I’ll add the second PR. So my only real dilemma was, do I put the PRs on one side asymmetrically or do I put one on each for a balanced look? But I just found a Klipsch 5.1 system with the same size drivers that are sealed, so I could bypass this PR issue all together, but where’s the fun in that
So first I’ll try it without the PR, just the driver, then I’ll add 1 PR to just the left speaker, then I’ll add the second PR. So my only real dilemma was, do I put the PRs on one side asymmetrically or do I put one on each for a balanced look? But I just found a Klipsch 5.1 system with the same size drivers that are sealed, so I could bypass this PR issue all together, but where’s the fun in that
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The box it’s coming out of is small, the cab it’s going into is larger. I’ll mount the PR(s) in the side of the cab even though the single satellites have a single upward firing PR
No, it's some time ago. Had problems tuning in 8 liters a 8 inch PR down to 30 hertz. Adding a lot of weight to a PR is critical and the vibration of a heavy mass exerts vibration to the box, too.
http://mh-audio.nl/Calculators/PassiveRadiator.html
http://mh-audio.nl/Calculators/PassiveRadiator.html
For me it's a myth that a PR is the solution for bass reflex in a small box. Especially if it should be tuned very low
Except that not being actual actve devices, it will be less than with push-push with drivers.
dave