Passive Radiators In Car Audio

A brief search on the internet showed many sites where DIY'rs have built home speaker systems using passive radiators. I have read the pros and cons of such systems and was wondering if anyone in this forum has used PRs in a car audio sub enclosure. If so, how did it perform? Do you have pictures or links? Thanks, Mike 2000 F150 Supercab Lariat, Alpine CDA-9831, Polk MMC570 in Doors, One Polk MM2104 Sub, One Polk Carbon C400.4 Amp.

John 3:16

I think some of the bass tubes and all-in-one systems that companies like Bazooka and Infinity make use passive radiators in their design. But I think most DIY'ers stay away from them, mainly because they are hard to incorporate into a system correctly.VEHICLE: 2002 GMC Sonoma ZR2

Alpine CDA-7940

AudioControl EQT x2

JL Audio 1000/1

JL Audio 10W6 (originals) x3

Kicker ZR120

Kicker ZR460

Polk GXR-6 x4

Polk GXR-4 x2

The Infinity basslink's use PR's. Paul

Yeah, they look complicated but seem to work well for enclosures where port tuning is impracticle - i.e. the port becomes longer than the enclosure. I am considering making an enclosure with an 8" sub and a 10" PR. Where would one purchase a good PR? Mike 2000 F150 Supercab Lariat, Alpine CDA-9831, Polk MMC570 in Doors, One Polk MM2104 Sub, One Polk Carbon C400.4 Amp.

John 3:16

all the original Kicker units used a 10" PR and they sounded ok....Kevin Gerry

Certified Electronics Technician

MECP First Class Installer

Owner/Installer

Classic Car Audio

since 1979

I have used them, and it was THE MOST incredible bass I had ever heard in a car. Did someone say DEEP?!?! I had mine in a 2.2 foot enclosure, using an Eclipse Ti 10 (the first generation) with a PR-15 from Adire, weighted for an Fp of 5.2Hz. Anechoic response was flat at 21Hz, and with cabin gain, I was getting 15Hz clean. There were two problems with the system. 1) the surround on the PR would invert TERRIBLY at medium output levels, introducing BAD flappy noises (sounded like one of those fart-can exhaust systems), and 2) the efficiency was not what I was looking for, so I got rid of that setup, went to a sealed enclosure (with the same woofer) and the Eclipse 4000 watt Digital amp. THAT was an output circus! If I had my druthers, though, I would go back to a PR system in the car in a hot second. They are VERY difficult to tune correctly, MUCH moreso than a vented enclosure, and a PR alignment is very sensitive to mis-alignment, much like a band-pass enclosure. Response will SUCK, if slightly mis-aligned, and there is a real probability of damaging both your expensive woofer and your 90 dollar PR. For a good place to locate high quality PRs, check with Kyle at Acoustic Visions. Good prices on great gear, and an AUTHORIZED Adire dealer...It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

"Alignment" - I here that a lot here in this forum but I have not a clue how it applies to speakers. Can you or someone else fill me on on "alignments" in reference to your above post? The bad flappy noises would be very discouraging. Is there any way to avoid such a thing or is it just part of the package when using PRs. I have to believe that those type noises are not par for the course based on the number of home stereo systems that use PRs. Do you have any pictures of your "old" system? Mike2000 F150 Supercab Lariat, Alpine CDA-9831, Polk MMC570 in Doors, One Polk MM2104 Sub, One Polk Carbon C400.4 Amp.

John 3:16

Here's a link that will help explain alignments a little better than I can... The bad flappy noises I was getting was from the surround inverting due to the EXTREME pressure variances exherted (sp?) inside the box when a PR and a driver are in proper alignment (tuning), and you are right... they were VERY discouraging. The only way I can suggest avoiding them might be a driver with an even stiffer surround (wow... good luck finding one of those...) than the Adire PR-15. I will tell you, the PR15 is an awesome PR, and will very likely work for pretty much any OTHER driver out there. The guys at Adire match it to their big woofers with very good results. (Steven, any input here would be appreciated) Unfortunately, there were no pictures taken during or after installation, or at any time during it's very short lifetime. The enclosure was scrapped, and the materials used in it became the materials for my new enclosure... a MUCH smaller, sealed box.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

I tend to steer away from PR in automotive practices purely because they are tuned so low.....they can a wave radius if 50ft! if your not careful!!!Check all advice given with a meter

Wha..? What does THAT mean? 23Hz is about a 50ft wavelength, but it has NOTHING to do with what type of enclosure it comes from... ANY driver making 23Hz is making a 50ft wavelength... I'd be interested to know EXACTLY what it is that you are saying, and what you mean by "they can a wave radius if 50ft! if your not careful!!!"It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."