philipbarrett
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Posts posted by philipbarrett
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I set my crossover at 40 Hz since the Khorns perform so very well in low frequencies.
Good conclusion. Professionally, we almost never allow 2 speaker enclosures to operate in the same frequency band for all the reasons your 1st plot illustrated (that & drivers being cranked into failure becasue the mixer cannot hear the true low due to cancellations). What you have now is a true subwoofer set up (emphasis on sub) where the natural roll off of the K's is complimented by the RSWs.
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Why do you feel that somewhat accurate measurements can't be made in a home environment? Won't a calibrated mic of reasonable quaility be able to measure what is there, warts and all?
I have used all sorts of room mode calculators since DOS was the latest OS. However, with some decent software, microphone and sound card, you should be able to take some relatively close measurements of what the mic is 'hearing' at a particular part of the room.
Audyssey hardware and software does this exact thing to flatten room response. I can tell you that it works very well.
Yes but what the mic is hearing at that point in the room is not going to help with your overall response throughout the room and is not enough of a representation to derive conclusions from. You are making a measurement that is completely dependent on exact frequency & exact location. It does not give a real indication of how the speaker is performing in the room, only how the room is interacting with the speaker at that exact point & time.
The best the Audessy (or any other processor) can do is quesstimate how that reading will translate throughout the listening environment and adjust accordingly. If you happen (for example) to place the measurement mic in a location that, due to room nodes, is 6dB louder at say 60Hz, the Audessy will happily pull that frequency down by 6dB even though 60Hz may be fine at other points in the room.
PJK neatly addressed the bass response problem by placing his speakers in the corners. As the simulation below shows, this is a very easy way to achieve smooth bass response throughout an environment.
Compare this with the room LF response of speakers placed along a wall -
My HO, through years of doing this for entertainment & a living is that the K's low end work's brilliantly just the way the man designed it. If "boom's" your thing, great, add a sub but don't confuse it with an enhanced or accurate low end.
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If you measured this with a sweep in an anechoic chamber stop reading right here.
If not, then what you are seeing is either room node cancellation, phase cancellation between the K-Horns & sub or more likely a combination of the 2. I know I'm back on my hobby horse but if you search my user name for previous posts you can see my opinions (& data) on why subwoofers disapoint with Klipschorns.
You cannot make accurate plots at these frequencies in the typical home environment the best you do is run prediction software. Here's a good place to start -
http://www.marktaw.com/recording/Acoustics/RoomModeStandingWaveCalcu.html
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The code was a marketing ploy, the idea being that you would spend more on a DDD disc (DigitallyRecorded, Digitally Mixed, Digitally Mastered). Even today, a huge number of releases are delivered to the mastering house in an analog format (1/2" 2-track being the most popular high-end) and of course the last "D" was meaningless anyway, how else were you going to master a digital disc anyway?
There are HUGE differences in the sound of CD players but $200 isn't going to buy you much, even used. If you can push your budget a little, the ever excellent NAD makes a nice entry single player the C-515BEE for around $300.
http://www.audioadvisor.com/prodinfo.asp?number=NAC515BEE
I've not heard it but the manufacturer is well known for packing a lot of sound into a simple package at low cost.
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I've had a 1020 since new, nice little piece, very transparent.
I love my little 7140 int amp, but it isn't transparent... it's dark grey (which I suppose sorta looks transparent when the lights are off at night).
So you want to go down that road eh, eh? Bring it on...
I shall talk about how the NAD involves me in the music, about it's pace & timing, light & airy yet solid with a defined musicality and interlocking detail. How it's presentation invokes feelings of detachment in a lateral imaging kind of way and it rendered the inner detail in a complex soundstage. Finally, I'll mention the dimensional body and dynamic contrast.
In fact it's so awesome I have to keep it in the garage with the propane tanks.
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I've had a 1020 since new, nice little piece, very transparent.
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Exactly, y'all are correct. The little Behringer will do a better job than DACs costing 10x as much (dare I say 20x?). As I mentioned before, there are better units out there but they cost substantially more. Mostly what you would be paying for are additional multitrack outputs, profesional mixing & processing capabilities that you wouldn't need anyway. You'll need 1/4" to RCA adaptors to hook into a home system, if you're on a PC then you'll install the FCA software, on a Mac it will be automaticaly recognized and If you buy from Muscian's Friend you get the option for a full refund if you don't like what you hear.
For easy switching between and assignment of system sounds away from the DAC I highly recommend the free Soundsource program from Rogue Ameoba (Mac only) - http://rogueamoeba.com/freebies/
Please let me know how it works out.
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Your cousin's analogy is an excellent one. Just as a car engine uses a timing belt to synchronize the mechanical functions so digital audio needs a timing clock to synchronize the data.
As discussed above, some digital audio signals contain this timing data which the receiving device can read and some signals require the receiving device to re-create the timing data. IMO this re-creation is where the most audible artifacts occur.
To confuse issues, some DAC (digital to analog convertors) ignore the signals timing data and recreate their own. This is common in the USB world where low end, off the shelf chips are used to build interfaces. A fantastic guide to Adaptive & Asynchronous USB can be found here (although I wonder about the author's use of expensive solutions to an inherent problem when the FW alternative is available):
http://www.computeraudiophile.com/content/Asynchronicity-USB-Audio-Primer
In a nutshell, Firewire offers the best solution at the lowest price. The FW audio signal contains a clock and all FW chipsets use this clock to synchronize their workings to the incoming data stream. Signal coloration is minimized, mostly leaving the analog section to define the "sound" of the system. Of course there are better and worse FW systems (professionally we use interfaces costing many $1,000s) but I believe that the clock resolution gives even the most basic FW interfaces the edge over DACs costing much more.
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I can ask this question since I am so sub-elementary ignorant: can & should the A/C wires be reversed, essentially reversing the plug like in the old days?
Bingo !! - I think you may have nailed it ! - I never thought of that, but it certainly was true of most old amplifers.
No, I looked at the schematic, the 1st thing the Pat-4 power line hits is a transformer which has no opinion on the hot/neutral issue.
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I am guessing that the dynaco pat-4 or kenwood had a 2 prong power cord and you replaced it with a 3 prong - IEC - Correct ??? If so, what I would do is disconnect the ground from the IEC to whatever you connected it to in the amp or pre-amp. - These units were designed for a 2 prong plug and you have probably made a ground loop by connecting the ground of the IEC to something in the amp or pre-amp.
Unless you physically added a ground wire on the IEC to the chassis of the Pat-4 then both should be floating which is what I believe the problem to be from the symptoms described (touching makes it better). The "ground wire" test mentioned in my last post should confirm or deny this.
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Take a regular (cheap) power cable and cut off the female (equipment) end. Strip back the insulation about 4" to expose the 3 wires inside & then cut back the black & white ones, leaving only the green. For safety, tape over the black/white ends.
Now, strip back about 1" of insulation on the green wire & using a clip, physically connect the copper strands to the chassis of your preamp, a place without thick paint would be best. Plug your modified cable into an electrical oulet.
Less hum? No hum?
PB
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Bridging amps such as the Samson is going to give you more problems than it'll fix. You'll be running the amp so close to it's voltage rails that power supply sag will rob you of sonics and headroom. The only amps I've seen that can really handle a bridged load do not plug into a standard wall outlet.
As Colin said "por que?" Are you running out of power?
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Ground noise can be caused by both "not enough" (equipment is floating & hunting for a ground) or "too many"(equipment is connected to ground in 2 or more places and their is a voltage potential between them) paths. I'm trying here to dissect your rather cryptic post.
1) you say "mainly on the phono" if that means there is also hum on other inputs I would suspect that the reason it's louder on the phono is the much higher gain from this input relative to the others - CLUE : if hum is present on all inputs then it's unlikely that the phono section is at fault or the caps or whatever you see back there
2) "if I touch the chassis it goes away" - CLUE : chassis is looking for a ground, you are providing one
3) "if I touch the postive wire it gets worse" - as it should, you're a great antenna & you've just connected yourself to a highly sensitive input
4)"I felt it necesary to replace the electrical cord and connected the ground to the chassie" if I presume this didn't fix anything then it totally contradicts statement #2
As mentioned above, without more information (the makes & models of your equipment would be a start) we can't go much further. Right now, basically all you've told us is that your car of undertermined age, model & make won't start!
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Pro audio runs at +4dB, home at -10dB, some amplifiers have an input sensitivity switch to compensate. If not the fix is simple & very cheap; turn up your preamp until the music's as loud as you want it to be.
PB
Its not that simple.
Care to enlighten us why?
What's not simple is the confusion around balanced interfaces & XLR connectors. The 2 are not the same. Search previous threads here for plenty of information on the subject & the reason why balanced lines make very little sense in domestic audio applications.
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Hey Thebes, I'll bet you can't make a three legged chair wobble
You said what I wouldn't. 3 legs is the way to go, the bolts allow perfect leveling of the shelves once the rack is placed.
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I think that's the Golden Ratio or some such thing.
I see you have wood floors & a turntable up top. Any problems with that setup?
I knew there was a reason for that, I think I did the math in mm too. I put the whole thing together in less than 3 hours from driving to Home Depot to gear wired, I just couldn't see spending big $ on a rack that could be spent on glowing toys!
The floor is typical Texas, parquet floor on concrete slab, pretty solid stuff in other words, so no problems even once the dance party & air guitar wars start.
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3/4" MDF & threaded rod, total cost >$30 at your local homestore. 3 legs is easier to balance & I recommend avoiding a leg at the rear as it makes connections more difficult Shelves are 16.75" x 23.25" which is either some kind of magic divisible number that gives low resonance or I forgot my meds that day!
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The pro amps take a preamp that has some kick to drive themt o full potential.
Pro audio runs at +4dB, home at -10dB, some amplifiers have an input sensitivity switch to compensate. If not the fix is simple & very cheap; turn up your preamp until the music's as loud as you want it to be.
PB
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Not the pinnacle of pro audio amps but a decent piece of kit, if it's used it may well have seen a hard life. These amps don't get bought to be babied. As for pro amps sounding "better" than others, search some previous threads on the subject.
PB
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This is the beautifully even coverage achieved by placing your low end in a corner, imagine that! The yellow lines are canceling nodes, there should be one but I probably had a sub an inch or so off in placement. In a perfect world it would be an infinitly narrow plane exactly between the speakers.
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...and here's what PWK has been trying to tell everyone for years
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So here I told the MAPP software to estimate a plaster ceiling, painted brick walls & carpet on concrete floor. I think you can see how using the 2 sub configuration is really detrimental to the sound once you get into a real world situation.
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I take it you would disagree with the following scenario (full range 2CH stereo):
Not all, I assume by "variable gain tube amp" you mean a preamp? My only concern would be loading down the outputs of the preamp. As for the crossover frequency, your ears should be able to tell you that. Subs stop really being subs above 100Hz, for home I would look at a 12db/octave crossover at around 60Hz which should blend in nicely with Heritage speakers run full range. Live I tend towards an Linkus R at 24db/octave but then I'm also high pass filtering the mains.
Mr P B, (noob Q) is sound cancellation just a problem in low freq, or is it a real and true problem acrss the 20-20,000 Hz range?
Happens at all frequencies but the wavelengths become so short that the time differences become minimalized. At 40Hz the wavefronts are at nearly 30 feet, by 1KHz they drop to around a foot and by 12KHz it's an inch or so. As you can see, mechanical time alignment becomes much trickier at higher frequencies.
I have always been told to listen to my older records in plain old stereo, without subs, because of this.
Old wives tale. Back in the days of vinyl, low end had to be controlled and mono'd in order for the cutter heads to create a groove that could be played back without the stylus jumping out of the groove (or the cutter burying itself in the acetate). There's plenty of low information on older records, either intentionally or unitentionally. If the subs make you happy leave them on, Bonham's 24" kick has all kinds of wacky stuff down there.
Mr P B / Colter, do you think my ability to tell directionality is due to sub cabinet vibration or adjacent brick a brack vibrating at higher than bass frequencies?
Also please tell us about your thought on the cardiod or directional sub trick.
Your hearing most of the directionality at higher frequencies. Put a 40Hz tone in there, eliminate the rattles (generally not possible of course) then try to locate. As for the cardiod subs; the MAPP predictions are not making this up, they really work if you have the room, processing & the $ to spend double the money (2 subs with 2 amps). I've set up big walls of subs in this fashion & watched stage hands walking in front & behind scratching their heads, it's that dramatic. Obviously room artifacts will come into play pretty significantly in the home but your area is pretty huge.
In fact that 1 sub in his room is even a contender for "umph" compared to my dualie 18"s.
Becuase his one sub is propagating per my 1st & 2nd predictions & yours are cancelling per the 3rd. It really is that simple. Further proof below.
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Now for the party tricks, or how to create directional LF with super-even coverage!
4) 2 subs stacked on the floor. The left (front) sub is placed 2 feet behind the right (rear) sub. The signal polarity is reversed to the front (sub is running "out of phase") and the front sub is delayed by 3.75ms (2 feet), combining it theoretically with the rear.
I've never tried this at home (don't have subs) but the approach would seem to be very workable in a larger listening room. Obviously the spacing is not critical, the time alignment just has to match. If you want the pattern to face the other way, time align the rear sub not the front.
edit : for clarity
Where do you crossover your Klipschorn and subwoofer for 2 ch. (plus sub) music?
in 2-Channel Home Audio
Posted
Amen Brother! Nothing frustrates me more than folks spending $1,000s on cables, convertors & the like then sticking them in rooms that sound like...er...well not very good.
One hundreth of what you laid out on that stuff spent on some simple DIY acoustic treatment will yield far superior results. Plus, these days there is so much help out there on the web.