kenratboy Posted April 8, 2007 Share Posted April 8, 2007 First, I have not posted in a long while, so hello again! As for the question, what is the maximum frequency response needed for non-critical listening - in that the point where you really notice the upper-end is lacking a lot? 10 KHz., 15 KHz.? Obviously, a lot is personal, but in general, what is your gut feeling? Thanks! Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 9, 2007 Share Posted April 9, 2007 How do you define "casual listening"? If you're not in the sweet spot, the power response is going to be a lot more important than the on-axis frequency response. As far as the top-end, I'd argue 10kHz being on the minimum side - but it's gonna depend greatly on how fast the top-end rolls off too... More importantly...why do you ask? Just curious about opinions, or you working on another project? Quote Link to comment Share on other sites More sharing options...
boom3 Posted April 9, 2007 Share Posted April 9, 2007 A LOT of variables here...if you mean 'background music" then typical background/PA system doesn't put out much over 8 or 10 KHz-nor should it. I have a 1960 Zenith radio in my garage, a 35 series output tube pushing a 3 x 5 speaker. If it goes over 8 KHz I'df be amazed, but it's good enough for Click & Clack while I wax the car or music while I make sawdust. The upper end will fall off as we age. I was rated as 5 dB down at 8 KHz and the audioligst told me that was excellent for a 50 yr old man. For middle-aged adults, a cut-off at 15KHz is rarely going to be noticed. Quote Link to comment Share on other sites More sharing options...
pauln Posted April 9, 2007 Share Posted April 9, 2007 The audio frequency range is a changing spread. Today the common spec is 20-20KHz. I'm reading a old book Basic Electronics prepared by the Bureau of Navel Personnel. It is the text by which they trained electronics and it is all about tubes, which is why I am enjoying it so much. The span in this book (1963) for audio frequency is 30-15KHz. I imagine the further back in time one goes the higher the low and the lower the high... Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 10, 2007 Share Posted April 10, 2007 How many navels in that book there, Paul? Quote Link to comment Share on other sites More sharing options...
pauln Posted April 10, 2007 Share Posted April 10, 2007 NAVAL... sorry Quote Link to comment Share on other sites More sharing options...
boom3 Posted April 10, 2007 Share Posted April 10, 2007 RCA's goal for a good high quality radio was 60Hz to 9Khz. The other interesting thing about their research into that matter was that there should be "bandwidth balance" in order for the sound to be perceived as "good." Balance meant that if you take some off the top, you also have to take some off the bottom. Or conversely, as you extended the top, you needed to also extend the bottom. Yeah, that "balance" notion got propogated in the Badimaff (sp)/Davis book sold by radio Shack that influenced a lot of speaker builders, including me. The theory went that the product of the top and bottom should be as close to 500,000 as possible. So... 30 x 15,000 = 450,000 100 x 5,000 = 500,000 etc. I never agreed with this. It really was a justification for the limited bandwidth of AM networks fed by voice-grade telephone lines and later the fact that FM had to be cut off at 15 KHz to avoid conflict with the 19KHz pilot tone. Not to mention the bandwidth of 78s. RCA and the other brown goods console makers fought "hi-fi" tooth and nail since they did not want to upset their relatoionship with consumers who expectede furniture and music to be co-equal. We're kinda in this situation now where the HT industry is conditioning people to expect speakers to be, if not invisible, then teeny-tiny. Quote Link to comment Share on other sites More sharing options...
OldGuy Posted April 10, 2007 Share Posted April 10, 2007 Back in the days I worked for a Telco in the program group We sold mostly 5 khz loops and sometimes 8khz. At that time a lot of musical remotes went through that sounded OK. but as we got into the digital loop world and prices went down stations contracted for better loops. It really comes down to the program material and your own approach. Do you listen to the music and the rhythm or do you listen for that extra bit of bite on a snare drum etc. Norm Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 10, 2007 Share Posted April 10, 2007 Ya know...if you wanted to play around with it yourself, I don't think it would be too difficult for me to put together a program that you could run on your computer that allows you to adjust a low pass filter being applied to a music file. And then you could hear in real time for yourself what you think is acceptable. Quote Link to comment Share on other sites More sharing options...
kenratboy Posted April 10, 2007 Author Share Posted April 10, 2007 Thanks everyone! I ask because I am playing around with full-range drivers (ordered some Tang Band stuff from Parts Express) - and while the 3" drivers are rated up to 20 KHz. most of the time, they lack power handling, mid-bass, and sheer output - however, step up to a 4" driver (better part of 2X the cone area and at least another octave on the lower end), and your upper-end only goes to about 14-17 KHz. (unless you get into the more exotic ones). Just seeing how much that matters - and I guess not a whole lot. BTW, the 3" drivers I bought...http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-814 ...sound REALLY good for what they are (obviously, you need a sub!). The mids and highs are really good, but mid-bass is lacking. My next step will be to get some 4" ones and start playing, if the mid-bass is a big better, and the lack of 15-20 KHz. isn't obvious, might be some fun mini-monitors. Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 10, 2007 Share Posted April 10, 2007 Hey cool - we're talking about doing much of the same thing for a speaker workshop we're doing here on campus. What kind of enclosure do you have the 3" drivers in? Btw, I think all of the K77 tweeters are only rated to 17kHz and often times are dropping down to 14kHz with age...just thought I'd offer a little relative perspective. What you're gonna notice more is the very narrow dispersion of the higher frequencies. It's gotta be like 10 degrees at the very top end. Quote Link to comment Share on other sites More sharing options...
pauln Posted April 10, 2007 Share Posted April 10, 2007 The picture on the partsexpress website looks to be actual size. Is that a misprint that the xmas is .4mm (less than 1/2 mm)? If so I can beleive the 3 inch cone has no mid bass... but the surround looks like its made for more excursion... Quote Link to comment Share on other sites More sharing options...
kenratboy Posted April 10, 2007 Author Share Posted April 10, 2007 Someone here can definetly explain better - but I think Xmas isn't the total available excursion, rather where it is accurate/within spec. For example, the JBL 2226 woofer has a very small Xmax (7.6mm) - but peak excursion is 1.6 INCHES!!! Quote Link to comment Share on other sites More sharing options...
kenratboy Posted April 10, 2007 Author Share Posted April 10, 2007 LOL - I bought 2 clearance birdhouses at some craft store (1/2" hardwood) for $0.99 each, and drilled the right size hole (filled with 'fill') - I need to get a Jasper Jig or something! Quote Link to comment Share on other sites More sharing options...
djk Posted April 10, 2007 Share Posted April 10, 2007 For small speakers the rule of 400,000 applies, the product of the HF and LF cut-off should be 400,000. EG: A small speaker cuts off below 100hz, the HF should start to roll off above 4Khz. Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 11, 2007 Share Posted April 11, 2007 Hey Kenratboy... I did some measurements of a few fullrange drivers and thought you mind find the frequency response plots interesting. Here's the TangBand W4-616SA: (click for larger image) And then here's 30deg off-axis: (click for larger image) Measurements were taken in half-space at 1m with a 2x4 foot baffle (don't ask) and then about 1.5 cubic foot sealed cabinet behind the driver. The dips you see in the low-end are room related and not related to the driver. The graphs were smoothed to 1/3 octave (the resolution of our ears). In the past, the IEEE and AES have been building the Dayton BR-1 speaker kits, but I think they sound awful and so I'm hoping to introduce a new kit this year. So far, initial listening comparisons have indicated that the TandBand sounds much better than the BR-1's. There's slightly less bass, but I think that can be remedied with a ported enclosure. I think we'll go with 0.14 cubic feet tuned to 80Hz. Peak output will be limited to about 103dB or so, but that should be fine for nearfield listening (ie, computer speakers). In light of the current discussion - as long as you're sitting on-axis the HF response is more than good enough. Anyways, there's good correlation between WinISD, the Partsexpress posted frequency response graphs, and the measured response which is always a good thing. I hope this helps. Quote Link to comment Share on other sites More sharing options...
garyrc Posted April 11, 2007 Share Posted April 11, 2007 It's psychoacoustically tricky, no? Can good engineering in the recording studio more than make up for limited frequency response? Within limits, perhaps. When VHS came out, about 1980 (before VHS HI FI, anyway), the specs showed an extreme drop above about 10,000 or 12,000 Hz, yet a few of those movies seemed to have more extreme high frequency content than several of my Lps played with a moving coil cartridge that was pretty flat (comparatively) out to 20K. A few of those VHSs were as interesting in the high end as VHS HI FI and CDs, when they came out in about '83, and produced the illusion of full frequency response on the upper end -- some really had shimmer at the top, beautiful string overtones, luxuriant cymbal crashes with very rich decay, etc. In those days I could hear anything a test record had to offer, and, in the same (somewhat live) room, with the same speakers as used with my VHS player, the demo on one of the JBL Sessions Lp that contrasted music with a 16 K cut off to "full range," I could hear the difference from behind the speakers (actually, this was true with either a speaker using an EV T35 - AKA Klipsch K-77 - or a JBL 075). If everything else is equal (including engineering, hall acoustics and listening room acoustics), I'd guess we would want response to 20K, but it is far from being the most important factor. Quote Link to comment Share on other sites More sharing options...
DizRotus Posted April 11, 2007 Share Posted April 11, 2007 Hey Mike, Is that one of the rescued drivers? Please let me know what becomes of them. I bet they'll all sound pretty good in a vented enclosure similar to the Tektons that mdeneen likes so much. Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 11, 2007 Share Posted April 11, 2007 Yes it is - and thanks again! [Y] We've got a crazy test and swap thing going on in the lab right now and have been changing stuff around and taking measurements. Sadly I've no means to take pictures at the moment, but I'll work on getting a camera to show off the craziness [] I'm swamped with tests for the next 2 weeks, but there should be a lot of experimentation this summer (I'll be doing summer classes and should have plenty of free time). We'll be experimenting with bessel arrays, 1/4 wave open baffles, transmission lines, etc... Probably reinventing the wheel, but it seems doing is the only way to learn about anything in this hobby (since everyone tries to keep everything a secret). One of these days I'd like to hit you up for the plans you used for the rear loaded horns you built. If all goes well we should be getting a permanent room and can start setting up everything to do listening comparisons...but more importantly, it makes it so that my car doesn't have to be a garage for storage... Quote Link to comment Share on other sites More sharing options...
DizRotus Posted April 11, 2007 Share Posted April 11, 2007 The attached pdf has the plans for the enclosures I built, plus a small vented box as an alternative. Quote Link to comment Share on other sites More sharing options...
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