MichaelShaffer Posted June 26, 2003 Share Posted June 26, 2003 What are the differences in sound between a speaker with a front port and one with a rear bass port? For instance the RB-5 and RB-75. Is it just more convienent to have a front port so you can place it near the wall or is there a difference in sound? Quote Link to comment Share on other sites More sharing options...
Mike82 Posted June 27, 2003 Share Posted June 27, 2003 When I had my shop, I sold Silverline (rear-port) and JM Reynaud (front-port). Based on my experience, the front ported speakers allow for near wall placement without mucking up the sound. If rear-ported were closer than 12", i found the sound was just plain bad. Optimally, a rear ported should have at least 24", but you canusually get by with 12-18" Quote Link to comment Share on other sites More sharing options...
Geo1 Posted June 27, 2003 Share Posted June 27, 2003 I agree with Mike82, but would just qualify one thing. The best distance from the rear wall depends to a large extent on the size of the port. Too far and you lose the bass reinforcement of the rear wall; too close and the bass gets smeared. A small port, say, 1.5 to 2 inches, on a small bookshelf speaker is probably best to be about 1 foot from the rear wall. A larger port, say, 4 or 5 inches, is probably best about 2 feet from the rear wall. The manufacturer is usually the best source for proper placement. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted June 27, 2003 Share Posted June 27, 2003 yeah mike, that's about it. front or back really just affects your placement options. frankly it always seemed stupid to me that many manufacturers place a rear port on bookshelf speakers which, by definition, will be on a shelf too close to the back wall. by RB-5's are like that...kinda dumb if you ask me...I suppose they do it to save front panel real estate, with the port on the back you can make the cabinet front just big enough to fit the drivers..I have never heard, nor heard anyone claim a different sound from front or back porting although someone out there may claim something along those lines. tony Quote Link to comment Share on other sites More sharing options...
Deang Posted June 27, 2003 Share Posted June 27, 2003 I always thought rear porting loaded the room better. Quote Link to comment Share on other sites More sharing options...
Mike82 Posted June 27, 2003 Share Posted June 27, 2003 I can't say I could tell the difference between front/rear port either when the speakers are properly positioned. I used to have the speakers set up about 1/3 of the way into the room (14' x 21' x 9' - short wall) That was the best placement, but I was fortunate enough to have a dedicated room. What cracks me up is when people spent $20K+ on a system , posting photos of their set-up, etc., and have the speakers (rear-ported) plastered against the rear wall, no room treatment, no toe-in, etc. I just know their rig has to sound like crap. Sadly, there's a lot of people with too much money and not enough experience buying $$$$$ components without taking other factors, just as critical to obtaining good sound, into account. As example from Audio Asylum. "I have $15K to spend on speakers. Any suggestions?" First, IMO 95%+ of the posters on AA are rank amateurs whose opinions I don't value. Second, if I were to spend that kind of $$$$$ on a speaker system, I'd be sure to know what I was looking for. Sorry for the soapbox. Quote Link to comment Share on other sites More sharing options...
Geo1 Posted June 27, 2003 Share Posted June 27, 2003 Don't apologize, you just hit one particular nail squarely on the head. Whenever I see a room like that I wonder to myself if the owner is disappointed, or thinks he/she needs to spend a couple of grand more on cables, or if that's as good as it gets. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted June 27, 2003 Share Posted June 27, 2003 dean, it's possible that rear porting MIGHT change the room loading, but the magnitude and effect of it would depend so much on speaker/port/room specifics that I prefer to not consider it apart from suggesting listening for oneself in ones room. I tend to think in magnitude that the port has more effect on the behavior of the active driver than as a direct contributor to the sound produced, ya know? regards, tony Quote Link to comment Share on other sites More sharing options...
toddc Posted June 27, 2003 Share Posted June 27, 2003 You mentioned the RB-75 and I'm just curios if ANYBODY has seen a real review on these yet. I can't find one anywhere online and I've been looking for months! When a new movie comes out and there are no reviews on opening day it's a pretty good indication that it's crap. Has Klipsch also released a bomb? Quote Link to comment Share on other sites More sharing options...
MichaelShaffer Posted June 27, 2003 Author Share Posted June 27, 2003 Well I just got my RB-35's today (which are very similar to the RB-75) and I'm a little disappointed. I don't know if I have them hooked up wrong or something.... Quote Link to comment Share on other sites More sharing options...
sunnysal Posted June 27, 2003 Share Posted June 27, 2003 what are you hearing michael? what sounds wrong? give some more details. reagrds, tony Quote Link to comment Share on other sites More sharing options...
MichaelShaffer Posted June 27, 2003 Author Share Posted June 27, 2003 sunnysal: Ok, I guess I was judging them too early. I turned up the volume and these things really rock! Quote Link to comment Share on other sites More sharing options...
IndyKlipschFan Posted June 27, 2003 Share Posted June 27, 2003 For those of us lucky to be here in Indianapolis, or come to Indy last week, we were treated to all the newer stuff Klipsch is now rolling out. The new front ported RB 35' and RB 75's (bookshelf front ported and their respective floor models too) in particular, and they were IMO way better than the synergy line and just a tad..(somewhat small) than the top of the line reference stuff too. Let em break in a while.. 100 hrs or more..doesnt have to be real loud just get all the parts broken in....Speaker wise and enjoy! Look at the new corner technology subs especially just coming out. In the test we all witnessed at Klipsch, they blew out a Velodyne and Polk big time, and at a price point everyone might consider it.. Trey Cannon with Klipsch is salivating to test a "SVS sub" If anyone is close to Indy they might come up with a Klipsch t shirt or something.. ESP if they could test it for a day or two?? They new subs are very musical, no harmonic BS... or octive BS.... to make em appear if they are more punchy. Just great LOWS, Solid lows.... Plus you can have a print out of your svs sub and what it tested out in a real anechoic chamber...Even the outside to infinity test...LOL.. IMO way cool.. Quote Link to comment Share on other sites More sharing options...
GooseChaser Posted June 27, 2003 Share Posted June 27, 2003 ---------------- On 6/27/2003 2:00:03 PM MichaelShaffer wrote: sunnysal: Ok, I guess I was judging them too early. I turned up the volume and these things really rock! ---------------- Michael, is the audio quality bad at a low volume or something? I am very curious as to what your earlier post was all about. Quote Link to comment Share on other sites More sharing options...
WMcD Posted June 27, 2003 Share Posted June 27, 2003 It is interesting that the very early Cornwalls had a slot in the back running the full height of the cabinet. There was a board just inside to form two paths going left and right. The geometry showed up in a Bell Lab publication and PWK must have seen it as a device which was well described in mathematical terms. That may seem an odd starting point. It seems that in those days, say the late '40s to early '50s, port design was not being otherwise done with a tube structure. It was kind of the dark ages of structures and how big to make them. For example, my nominal uncle (dad's buddy from high school), a first class technician, told me how bass reflex peakers at the time were designed by making just a square hole in the cabinet. It was only as deep as the plywood. By some sort of temporary sliding or tacked on wooden plates, the size of the hole was varied. The test for the correct size was to hold a candle in front of it. When the bass blew out the candle, that was the correct size. Later the Cornwall got a retangular tube at the bottom of the cabinet with the port in front. We can only infer he saw advantages to a front port and the drawbacks of a rear port. There may be some reasons to choose putting the port in the back. Relatively small ones can create "chuffing" sounds. Tomlinson Hulsman (sp? THX) in one of his books, called it "port noise complaint." I winced and sent him some e-mail. The chuffing noise may be suppressed if the port is in the back. In the Cornwall the port size is quite large. So there should be no chuffing. Gil Quote Link to comment Share on other sites More sharing options...
Marvel Posted June 28, 2003 Share Posted June 28, 2003 Gil, "port noise complaint", that's a good one. I have these small Alesis nearfields that I use for my recording studio, and the ports on them are on the back. They are supposed to be out from the wall a certain distance, but I actually have them ON shelves. Most people probably wouldn't. I'm not quite sure what it is doing the the sound. Their biamped model has the ports in the front. Altec used to have a method of making the prot the correct length by feeding a sweep signal and measuring the levels. You would get two peaks. When the peaks were the same height, the port was supposed to be the correct size. It could be done at a low volume as well, so you didn't risk hurting anything. Marvel Quote Link to comment Share on other sites More sharing options...
MichaelShaffer Posted June 29, 2003 Author Share Posted June 29, 2003 ---------------- On 6/27/2003 6:24:55 PM GooseChaser wrote: Michael, is the audio quality bad at a low volume or something? I am very curious as to what your earlier post was all about. ---------------- not bad quality, just different. I'm letting them break in then I'll report back.. EDIT: Ok, I these speakers sound incredible, but they don't have much bass, I definitely need a good subwoofer. The midrange and highs are really really good though at any volume. Quote Link to comment Share on other sites More sharing options...
hightone Posted June 29, 2003 Share Posted June 29, 2003 Congrats on your rb-35 purchase .I just picked up a pair today myself and they do open up very nice indeed when you give them a bit of volume. They do rock. I was suprised at the bass response they have. At any rate I am happy with my purchase. Quote Link to comment Share on other sites More sharing options...
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