Front firing passive radiator, rear firing woofer?

[Muzak + Klipsch]

So I am new to Klipsch, (first owned system: Jan 03 ) but not to HT. Now I admit that I am not the most knowledgeable person on this subject (I'm asking the question aren't I...or atleast getting to it?) I used to think that Bo$e was a kickn' system, and my actual dream system for while was the

Lifestyle 50. Anyways, after I heard the first note played by the Commercial Audio Series/Installed Products/IN-CEILING IC-6T speaker I was hooked. I am an Account Executive for Muzak (Hence the name: Muzak + Klipsch) Muzak is the exclusive commercial retailer for Klipsch. Mainly, we are their key ingredient to working with companies like Red Lobster, McDonalds, Harley Davidson, etc. That's Muzak's core business, and we've been doing it for 70 years. Goto: www.muzak.com for more info on this legend in sound.

Anyways...to my question....

Passive radiator, rear firing woofer? What's the concept,how does it work, so on and so forth?

If you have any additional questions that you want ask about Muzak, I will be happy to answer them. NOTE: I recently dislocated/broke my shoulder "OUCH!", and also had major surgery on it . I have one hand to type with (It took me atleast 45 mins for all this) If you really want a good answer say so, and give me a day or two!

I appreciate the knowledge that you all bring to the table, and look forward to your insight on this question.

[JohnA]

You must be asking about some of the new subwoofers. The passive radiator produces the deepest frequencies. Having it forward may reduce the higher frequencies produced by the woofer. When used correctly (crossover below 100 Hz) it won't matter which end faces forward.

[WMcD]

Ouch.

Years ago I fell on some ice while jogging at the Chicago lakefront. Broken the right wrist from trying to break the fall. As you say, typing slows down. I survived some meetings by taking notes on an HP-200 LX palmtop.

What you're asking about goes by a few terms. Passive radiator or drone. It is typically put on the back of a system simply because that is where there is some available space.

The use of passive radiators is somewhat a recent development. However, it is a variation on the ported or bass reflex system, which has been around for at least half a century.

The main "woofer" works over a wide range of bass (low) frequencies. The mid and tweeter take over at higher frequencies. Let's just assume the woofer is working from 60 Hz to 700 Hz. We'd like to make the system, overall, work down to 40 Hz.

There is some engineering and physics to it. The short story is that the passive radiator/drone, or port, can use the energy from the back of the woofer (which is otherwise trapped in the box) and radiate it over a small range of frequecies. So it fills a gap at the bottom end. In my example, 40 to 60 Hz.

Gil

[Muzak + Klipsch]

So basically it's an additional subwoofer, or a dual sub enclosure with one sub accenting the other?

[Professor.Ham.Slap]

----------------

So basically it's an additional subwoofer, or a dual sub enclosure with one sub accenting the other?

----------------

Not really... The passive radiator has no magnets. It just uses the compression and decompression of the air in the sub box created by the active woofer to move the passiver radiator.

[Muzak + Klipsch]

I see...so the woofer(radiator) acts as the port in a way, but instead of allowing the air(energy) to just die the radiator continues to move it, and allow the lower frequencies to be produced? If that is right, why not just have a long port instead?

[Professor.Ham.Slap]

First of all there is absolutely no port noise, and unless I'm mistaken, it also ups sensitivity.

[JohnA]

The passive radiator is just a substitute for the port. One big advantage is that it limits the max excursion of the woofer below resonance where a port cannot.

[arena]

sorry to go a little off subject, but i bought a pair of rp3s off ebay over a year ago, and absolutely love them. my friend was so impressed he bought a pair of rp5s off ebay a few months ago.

initially i expected to be more impressed with the bass response of the rp5s, which extend down to 25hz, vs the rp3s which only go to 27hz, as i though one or two hz at this low frequency would be really noticable.

however, when i actually heard the rp5s, the bass didn't sound as tight as the rp3s, but instead sounded loose and less controlled, even "coughy" or thuddy in the lower frequencies. when i realized the rp5s employed ported bass (after hearing them i went over to the cabinet to check things out), i attributed this decrease in bass quality to the ported cabinets.

is this a reasonable assessment of the situation? if so it seems that porting a cabinet is kind of like "cheating" a few extra hz at the bottom end, so that porting is a compromise between bass extension and quality. is there any truth to this?

if so perhaps passive woofers are the solution to this problem.

[Strabo]

The bass tightness will also depend on what amp is driving the speakers. You may be hearing differences in the amps.

[dougdrake]

arena - Possibly several factors at play here. Placement will affect the sound quality of the bass. So will the room - standing waves and whatnot. Unless you listen to them both in the same room, in the same place, it's kind of hard to make a 1:1 comparison.

However, your comment about porting possibly causing some "slop" has merit. A sealed enclosure, like the RP-3, controls the woofer by air compression at the possible expense of spl's and depth. A ported enclosure gains volume/depth but there is no "back pressure" to control the woofer travel, which could lead to boominess/slop. A passive radiator is a compromise between the 2 as it remains virtually a sealed cabinet, but does allow bass pressure to "escape" via the radiator.

Also, you are dealing with 10" cones versus 12" cones, and smaller cones "typically" (but not always) will sound tighter as they are easier to control, in theory.

Or so I've read

DD

[easylistener]

What did Muzak make?

By the way, the shoulder problem, the same thing happened to me at work. I have had three surgreys and they still can't fix it. I have to find another line of work. so good luck and I have been there. Keep up with theripy because it does help in the long run. You will probably have to lift light weights your whole life from now on. As soon has the shoulder gets a little weak it will dislocate agian. What surgry did you have? Maybe I can help you out. I am still looking for a great surgion to try one more time to fix mine.

[arena]

----------------

On 4/30/2003 7:39:47 AM Strabo wrote:

The bass tightness will also depend on what amp is driving the speakers. You may be hearing differences in the amps.

----------------

oh yeah, i forgot, we are both using identical amps: harmon kardon hk3370s.

as to the room size, my room is 11.5 feet wide by 20 feet long, ceiling 8.5 feet high. my friends room is about half that size (same ceiling).

as to the size of the subs, i was under the impression that the additional 110 watts in the rp5 amplifier would help negate the fact that it was pushing a larger woofer.

so if internal compression helps control bass travel for tighter bass, why allow bass pressure to "escape" through a port or passive radiator? just to squeeze out a few hz on the low end or a few more spl?

thanks again for all the info.

[Muzak + Klipsch]

What did Muzak make? I don't know what you mean but my surgery was just a pull together of the shattered fragments of my arm bone. They put my shoulder back in socket and put the bone back in place with screws and then had to staple me up. I wear a sling for 21 days and actually this week I feel a ton better. Fortunately for me, I don't think my injury was as bad as yours because my doctor said that I am healing up well and I have decent mobility now. Thanks for asking, I appreciate it. I hope you get well too!

Not long ago I got my complete 35 series in and hooked up. I think I am one of the first people to hear and own the new 35 series and I tell you what...BAD ***! A definite upgrade needed by any former 3 series owner. You can see by my signature the setup I have. I plan to upgrade my receiver in the next 6 to 9 months so I am looking for some suggestions. Maximum spending limit $1200.00.

Thanks for all your advice,

[Ou8thisSN]

doesnt the SVS subwoofers implement Port designs instead of passive radiators? why do people rave about them?

[TheEAR]

Why do people rave about SVS? Simple

Well designed subs,great performance at a realistic price.

SVS puts money first where it should go first,the woofer(s),then the amp/crossover and finally the cabinet.The cylinder cabinbets are sturdy and inexpensive,most of the money goes on the woofer/amp.Not the cabinet

As for port VS passive radiator

For maximum SPL the port winns,for a music sub the active/passive combination gets my vote.Note a well designed flared port will have minimal noise even at high SPL(if its not underported and flaring is well optmised).

[Ou8thisSN]

well, i was thinking about a two channel system with the PB2+, for that price, should I consider the RSW15 instead? it will be strictly for Musical duties.

[prodj101]

a passive ported enclosure gives you the positives of both a port, and a sealed enclosure. in a ported box, the low end is increased because you can change the length of the port to get the desiered frequency response. the woofer is also allowed to move much farther because it has no resistance from the compression inside of the box. ported boxes however often have port noise at higher volumes, and are less clean sounding.

in a sealed box, the efficiency is decreased considerably and the low end also often suffers, unless you have a very large enclosure. however, the compression inside of the box forces the woofer back to it's orignal position, which gives sealed subwoofers the tight and clean sound they are known for.

In a passive radiator box (with a passive driver, as found in the RSW speakers), the passive woofer is driven by the compression caused by the active woofer inside the box. when the active woofer moves out, it would creat a lower pressure area within the box forcing the passive woofer to be pulled in, so it would look sort of. ->[]-> if the arrow on the left is the passive woofer and the arrow on the right is the active woofer. the passive woofer helps to increase efficiency of the design, and also increases the bass extension, while still maintaining the tightness of a sealed box. also, because there are no ports, they are much less "boomy" and will generate NO port noise.

I hope this answers your questions

[Ou8thisSN]

so... basically, do you recommend the RSW15 for music and the SVS for HT? I want bass that hits hard, but isnt boomy, all the reviews suggest that SVS isnt boomy, but they did find some port noise, but they said the RSW15 comes nowhere close to the performance of the SVS at lower frequencies. Its a given that SVS outclasses the RSW15 in movies, but what about music? I want a muwsical sub to fill an area of about 4000 sq feet. I listen to trance, dance, and rock. I like heavy bass lines. If you were me and had 1200 to spend, which would you get the SVS PB2+ or the RSW15?

[prodj101]

RSW-15!