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Post by duke on Aug 29, 2017 22:55:11 GMT -6
I've really enjoyed reading this thread. I'm not one of you guys, just a speaker geek. But I've been consistently impressed with how conscientious and competent you guys are, and this thread is like a peek into how your minds/spirits work.
Gotta admit this stood out to me, pulled from one of jazznoise's posts: "I learn things, I read a lot of technical papers, and I try to apply that understanding creatively." Me too.
In my world, the analog of "mixing" would be "crossover design."
In the first or Measurements stage, math totally rules, so I'm probably a "1". I run a LOT of measurements - gotta have good data and LOTS of it.
Next comes the Design stage, now I'm a "4", the shift being to make room for psychoacoustic considerations, but if anything I'm actually using MORE math.
Finally comes the Tweaking stage, and now I'm probably a "C"... I'm mainly listening (and FEELING) for WHAT'S WRONG, using psychoacoustics and math to figure out what might be causing whatever problem(s) I still hear, and then using math to devise a solution. So at this final stage, how it sounds/how it feels is the master, and math has become the servant.
Yeah I know that probably has little if any relevance in this thread... which is why I posted the short version...
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Post by duke on Aug 10, 2017 18:14:32 GMT -6
Apparently I've lost the ability to quote, so I'll copy and paste: "Anyone see an issue with this? www.amazon.com/gp/aw/d/B00LNOAGZQ" I looked at some of the reviews and at least one person is reporting a POP when switching between amplifiers. You'd have to decide whether that would be a deal-killer for you.
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Post by duke on Aug 10, 2017 1:02:59 GMT -6
Most solid state amps approximate a constant-voltage source, which means that they put out more wattage into a low impedance and less wattage into a high impedance. Most loudspeakers are designed with constant-voltage amplifiers in mind.
Tube amps usually approximate a constant-power source, delivering approximately the same power (wattage) across the spectrum as the impedance curve swings up and down, unless the swings are really big and/or go outside the range the amplifier was designed for.
Let me explain how a problem can arise from the different behavior of these two amplifier types (I'll be making some simplifying assumptions but the principles illustrated are correct): Suppose a hypothetical "8-ohm" speaker was designed for solid state. Let's say its impedance curve has a 16 ohm peak at 50 Hz, the impedance dips to 4 ohms at 200 Hz, and there is a 32 ohm peak at 4 kHz. So when our constant-voltage solid state amp is putting out 2.83 volts (1 watt into 8 ohms), it is putting out 1/2 watt into the 16-ohm peak at 50 Hz; 2 watts into that 4-ohm dip at 200 Hz; and only putting 1/4 watt into that 32-ohm peak at 4 kHz. Since the speaker designer expected this, all is well - the speaker sounds balanced.
Now suppose we decide to try a tube amp, which puts out approximately the same wattage across the spectrum. At 50 Hz, the speaker is getting twice as much power as the designer expected (+3 dB), so the bass sounds bloated. At 200 Hz, the speaker is getting one-half as much power as the designer expected (-3 dB ), so the lower midrange region sounds thin. And at 4 kHz, the speaker is getting four times as much power as the designer expected (+6 dB), so the speaker sounds harsh. Our instinct would be to conclude "tube amps suck", but really the culprit was a component mis-match.
It is not too difficult to design a loudspeaker to work well with a low-damping-factor, constant-power-approximating tube amp, as well as with solid state amps. The secret is, make the impedance curve very smooth over most of the spectrum, and use a variable-tuning port system so you can tailor the port tuning to your particular amplifier damping factor/room-induced low-end boundary reinforcement situation. (With tube amps in particular, amp + speaker + room = a "system".) So IF you are going to try a tube amp, unless you know the speakers were designed for tubes, take a look at the impedance curve. Amphions were mentioned - their impedance curves don't swing as wildly as my hypothetical "8 ohm" speaker above, but their nice flat frequency response curves (measured on a constant-voltage amp almost certainly) will be modulated somewhat by the impedance curve when driven by most tube amps.
That being said, even with compatible speakers, I would not suggest relying on a tube-amp-based monitoring system because I think it could potentially sound "too good" and result in a mix that doesn't translate well to lesser systems. But a good tube-based system just might be killer when it's time to "impress the client".
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Post by duke on Jul 27, 2017 22:31:34 GMT -6
Monitors with accurate response and huge headroom to my ear make everything sound better than what the recording will ultimately be listen to on. I have gotten fooled by really good monitors. I've been trying to figure out "where the goal posts are" for project studio monitors, and, at the risk of over-generalizing, it seems such speakers fall into two broad categories:
- Monitors that are as accurate as possible given the constraints; and
- Monitors that are inaccurate in ways which encourage a mix that sounds really good on a wide variety of systems.
Seems to me the second kind is the more valuable tool, especially if the first kind can fool you into thinking your recording sounds better than it is going to out in the real world.
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Post by duke on Jul 2, 2017 22:19:39 GMT -6
Very true, but we have to remember the image we are presenting is a sythisized image, the image presented by the large Magnepans, Quested H208's TAD's and Vandersteens are all different. This is a major part of why I won't mix on the Magnepans or Quad ESL's . A big part is the matching of Drivers and crossover fo consistent phase interaction. While I agree with Duke I have heard excellent soundstage on the old Infinity IRS with the big curved baffles and some ATC's with some pretty large baffles, so like I said sum of the parts. We also have to understand that soundstage has a lot to do with placement and besides the physical limits rooms and life in general will place on placement, position is often a compromise of various so ic factors, more often than not bass and soundstage performance. Good point, I should have made it clear that I was NOT suggesting Maggies or somesuch for mixing - just offering them as an extreme example of the effect of behind-the-speaker wall-bounce on soundstage depth.
A big smooth baffle may well be the best from an imaging standpoint, especially if the cabinet edges are at least .68 milliseconds (9.2 inches) away from the drivers. One of the best-imaging speakers I can remember was the Snell Type A, with a two-foot-wide curved baffle hidden under a grille. Never got to hear the Infinity IRS.
* * * *
I found a YouTube video that imo offers a demonstration of the relative effects of early vs later reflections on depth (among other things).
This is a talk given by David Griesinger. His specialty is the acoustics and psychoacoustics of concert halls, and in this talk he plays some interesting clips. The clips start at 13:19, and go to 15:02. These might be best heard over headphones, just to exclude a second set of room acoustics, even though headphones don't really present a natural image... I think the point will come across anyway.
In the first clip, we have the direct sound only. It's time-gated to exclude all reflections, and this in turn excludes the longer wavelengths, so the tonal balance is unnaturally thin. The point is that the voice sounds "proximate", or close to the ears (and thus lacking in depth), when reflections are absent.
The second clip is the direct sound + first reflections. The first reflections degrade the clarity of the singer's voice. The timbre is warmed up because the time gating window is open for a longer period of time, allowing the longer wavelengths to be included. Depth is still fairly "shallow".
The third clip is the most interesting: Direct sound minus the first reflections, plus all of the later reflections. Now we have depth and spaciousness! And imo we also have timbral richness and good clarity.
The final clip is of course everything: direct sound + first reflections + all later reflections. Depth is still good, timbre may be a bit more natural, but imo the clarity of the singer's voice is degraded relative to the previous clip.
So in the context of "what makes a speaker have depth?", I think these clips show that later-arrival in-room reflections can be beneficial in a number of ways, including imparting a sense of depth, but the early reflections are not very helpful. Of course the timescale for a concert hall is quite a bit different from the timescale for a project studio, but I think the same general principle still applies... in other words, I think that minimizing the early reflections while retaining later-arrival reverberant energy is beneficial.
I have worked with this concept fairly extensively in home audio, using techniques that would not be appropriate for a recording studio. I can describe them if anyone is interested. But briefly, the conclusion is the same: The less early-arrival reflections the better, and (up to a point) the more later-arriving reflections the better (as long as they meet certain criteria). For the rooms I work with in home audio, anything before about 10 milliseconds is "early" and anything after about 10 milliseconds is "late", but the transition is a lot fuzzier than is implied by specifying an actual number.
I think this general principle has implications for speaker choice, and speaker positioning, in a project studio.
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Post by duke on Jul 2, 2017 20:37:41 GMT -6
What do you guys think makes a speaker have depth? For good image depth, imo we don't want any significant reflecting or diffracting features on the baffle face or nearby. Reflections or diffraction that occurs within about .68 milliseconds of the first-arrival sound is especially likely to be detrimental to imaging. After that, the precedence effect kicks in, and helps to reduce the image-shifting tendency of early reflections. But in general, any early reflections are detrimental to imaging.
The speaker's frequency response can have an effect ... a "smiley-face" curve tends to make the vocals sound more distant, while a "frowny-face" curve tends to bring them forward.
Imo speaker/room interaction plays a significant role. The ear/brain system judges the size of the room, and to a large extent the depth of the soundstage, from the time differential between the first-arrival sound and the onset of reflections. In particular, reflections off the wall behind the speakers play a role in soundstage depth, and at least in un-treated listening rooms, it is unusual to get soundstage depth significantly deeper than twice the distance from the front of the speaker to the wall behind it. So if the speakers are 3 feet out from the wall, it would be unusual to get a soundstage that seems to go deeper than about 6 feet behind the speakers - at least that has been my experience in untreated rooms. I don't think this limitation applies to a good flush-mount installation. Anyway one implication of this is, you can often increase the soundstage depth by pulling the speakers out into the room a bit further. Whether this is an overall net benefit or not probably depends on the specifics.
Some types of home-audio speakers are known for having very good soundstage depth when set up properly, and can serve as an example of the principle described above. For instance, Magneplanars tend to have very good, solid soundstage depth when positioned at least five feet out into the room. Their strong backwave reflection off the wall behind them is pretty much what establishes the "onset" of reflections, and it happens after a long enough time delay that the sense of depth and spaciousness are both pretty good.
The ear/brain system does infer a sense of immersion and envelopment from very low-frequency energy, even if it's just hall ambience instead of actual music signal. Even moreso if there is a phase difference at each of the ears, as with a recording that has good stereo separation all the way down. Over in the home audio world, some people synthesize this phase differential, and thereby the resulting sense of immersion and envelopment, by using a technique suggested by David Griesinger: Use two subs, positioned to the left and right of the listening area. Set their phase controls 90 degrees apart - in what's called "phase quadrature" - and this offers a good combination of low-end extension and convincing sense of envelopment. In my experience you can further increase the sense of envelopment by going all the way to 180 degrees phase differential, but this results in less low-end energy because at very long wavelengths the dominant interaction is cancellation.
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Post by duke on Jun 24, 2017 18:15:53 GMT -6
It seems to me the site owner usually sets the tone for a site. Those more or less in tune with him will be comfortable there, and others won't be. I think John has really good tone.
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Post by duke on Jun 24, 2017 14:58:58 GMT -6
Edited: I misunderstood the question and my response was of no value.
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Post by duke on Jun 23, 2017 22:15:24 GMT -6
No thoughts that would be of value. #firstTimeEverTypedOnInternets ...I just wanted to clarify what the DR reference being made was about.... Your clarification about DR was quite educational! I'm the one who came up with a tangent and then tripped over it...
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Post by duke on Jun 23, 2017 14:28:46 GMT -6
DR=dynamic range. As measured by the offline analysis tool: found here dr.loudness-war.info/Speaks to the mastering dynamics of a retail release. It's not a simple RMS, but think of it that way---it's a kind of algorithmically averaged peak to valley range. DR6 is a normal modern master. DR11-14 were 98% of masters from 1973-1995. The 50/s60s recordings (meaning of pop/rock) lacked....they were more like DR9-11 due to the lack of fidelity of the old tape machines....and lack of VCA compression to make transients punch harder....and various stylistic balance preferences. In the early/mid 90s, lookahead limiters changed that now that there was no need to master for vinyl, where DR14 was actually "louder" and less noisy on playback than DR8....on CD, lower range=louder. So, the irony was that the shift to a format that could represent MORE dynamic range.....manifested into less and less. Thank you very much! I didn't realize how precisely a specific dynamic range could be targeted. Sad how, now that so much dynamic range is finally available, market demands keep it from being taken advantage of.
Over on the speaker design end of things, at least in home audio, preserving the dynamic range on the recording is imo a worthwhile goal. As the SPL goes up, drivers can be susceptible to "thermal modulation", which is like a short-time-constant version of thermal compression. Thermal modulation can soften the peaks, and when one driver has more thermal modulation than the others, the tonal balance can actually shift on peaks. Thermal modulation has not been investigated in depth like thermal compression has, but I have it on reasonably good authority - conversation with Floyd Toole - that it's a real thing. Toole told me of measuring a high-end home audio speaker whose midrange driver exhibited 7 dB(!) of thermal modulation on peaks at SPLs in the lower 90's, whereas the woofer and tweeter had essentially negligible thermal modulation. I believe a certain fairly widely-respected studio monitor has just the opposite going on, with the midrange driver having audibly less thermal modulation on peaks than the woofer and tweeter, but I have no measurements to back up this theory. Anyway the "brute force" solution is, to only use drivers which have a lot of thermal headroom left in the tank even on peaks.
My guess is that ideally you'd want well thought-out, "representative" thermal modulation on mixing monitors (in the interest of getting a mix that translates well), but that you probably wouldn't want any thermal modulation on tracking and mastering monitors. Any thoughts about this?
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Post by duke on Jun 23, 2017 12:57:02 GMT -6
John, what near fields have you found workable? Hey - Don't take my word for it -- But Equator. D5's and D8's. (Deleted the rest of a long, brand-specific rant as to not offend). Actually considered building a surround rig based on the D8's (but able to sum to the Tylers). Might still do it some day, but surround requests are so rare... That said, if I had a decent surround rig, maybe I'd get more requests. #ChickenOrEgg I had to look up Equator, and imo that is a VERY INTERESTING design! The D8 in particular is a relatively big (8" cone) coaxial - bigger cone than normal for a little nearfield monitor, which translates to better radiation pattern control and (because the cone is the "horn" for the tweeter) a bit higher SPL before woofer cone motion starts to degrade tweeter clarity (one of the limitations of a coaxial that doesn't use a separate horn). I like their design choices and am totally intimidated by what they offer at such a modest price. Of course none of this tells me how the speaker actually sounds, but the design choices that I can see look very intelligent to me. Coaxial is one of two formats I'm looking at. And personally I prefer the woofercone-as-horn format Equator uses for their D series versus their Q series, with its separate coaxial horn.
Thank you for mentioning these.
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Post by duke on Jun 23, 2017 12:32:36 GMT -6
It happened that i just worked the whole night on the mix of a super low budget recording of a death metal band that happens to be my next (live) band after 20 yrs. of not playing in a traditional band project... What a story......... (Nobody asked for levels or preferred DR, so the sampler would work anyhow...so DRs and levels may be all over the place...)For this genre i chose to go down to DR7 finally, while my favourite mix was DR14, but i am pretty sure it would go lost on this sampler. And yes, it will make it to physical media (CD), not just online....the musicians performances actually are quite good under these circumstances. So it might work out anyhow... Thank you for the in-depth peek behind the curtain at what you sometimes have to deal with! Is sounds like those guys are lucky to have you, and that you are giving them the very best shot they could hope for under the circumstances.
Please pardon my ignorance, but what is "DR" in this context? DR7 vs DR14?
Thanks!
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Post by duke on Jun 22, 2017 19:15:53 GMT -6
A live show that sounds like a record through a massive Hi-Fi system is the ideal... And over in the audiophile world, a massive hi-fi system that can make a record sound like a live show is the ideal...
But seriously, I totally get what you're saying.
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Post by duke on Jun 22, 2017 12:47:14 GMT -6
No worries Duke. I record using Logic X. There's an automation feature. It gives you a line across the track you want that represents volume. Basically, you can raise or lower the line (volume) as much or as little as you want at any place in the track, even for one small part of one note. The volume will then automatically change where you programmed it to. Thank you Martin. Wow, that's a powerful tool!
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Post by duke on Jun 22, 2017 11:36:16 GMT -6
What do you guys do when one bass note rings too loud? Even when I automate volume, it's never right. Apologies for another newbie question... what does it mean to "automate volume"?
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Post by duke on Jun 22, 2017 11:33:32 GMT -6
Trusting your speakers and your room down to 20Hz is a big ask. It's down to your ability to hear frequency bands, your auditory mapping (that sounds like a bass note ringing too loud, the sub-bass synth line has too much of its 2nd harmonics, the bass and the keys are beating on certain lower notes etc. etc.), the acoustics of the room, the speaker quality and the loudness you listen it. Duke, would you consider trying to get the experience of a day's studio work for yourself? There's no better R&D than to actually see what your client does, or even try to do it and see where the difficulties lie. It's the same for us - being in a band informs how I approach recording artists. YESSS!! A day of studio experience - what a fantastic idea! THANK YOU!! Wish I was in Nashville where a lot of this site's members are... but a quick Google search turned up a solid 2+ pages' worth of studio names here in the Dallas area.
Reports I've gotten from home audio users about the measured in-room frequency response smoothness of my little distributed multisub system have made me optimistic about the technique's potential benefits in a small studio. And given that speakers + room = a minimum phase system at low frequencies (in small rooms), this smoothing of frequency response is simultaneously reducing modal ringing. This makes the job of bass trapping easier, and in theory EQing should also become easier.
Trustworthy down to 20 Hz is indeed a big ask... usefully smooth in-room all the way down to 20 probably won't be feasible in smaller bedrooms, the devils always being in the details of course. But I think "worthwhile improvement" will probably turn out to be generally feasible.
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Post by duke on Jun 22, 2017 0:35:29 GMT -6
Wow, thank you all so much for your in-depth replies! I learn things from you guys that I never would have thought of, and that are not in the books I have. Thank you all for taking the time.
I can't help but be amazed at how you guys find ways to work around a small room's limitations... trusting your experience, watching the cone motion, moving around the room to listen in different locations, using software, paying close attention to meters, using many different pairs of speakers (including headphones) that you know well...
I wondered about using the same space for recording and mixing, whether an inherent "room sound" would make it hard for you to tell what was on the recording vs what the room was contributing as you mixed or mastered. But it sounds like once you know what's happening in your room, you can take it into account.
I've had the good fortune to work with acoustician Jeff Hedback on a few projects, and in fact he's the one who told me to come here instead of going to that purple site. Ime his rooms sound very neutral and natural (no characteristic "room sound" that I could detect from listening to my own voice). And FUN... when I closed my eyes in rooms where he had done the acoustics, the rooms felt about twice as big as their actual dimensions. That really impressed me. So I'm trying to learn more about what you guys do to deal with small rooms so that, if I get the chance to do a speaker system for small rooms, I'll hopefully have a better idea of where the goal posts are. Whether it's a room treated by a professional acoustician or by a hard-core engineer on his own.
For instance, it sounds like in-room clarity down low is a big challenge, especially with content down into the bottom octave. That's not surprising, but it's good to hear it from you guys first-hand. I love a well-defined challenge.
And I'm also interested in John's opinion on nearfields, given that he likes Tyler Acoustics speakers in (what looks to me like) a mid-field-ish setup. I'm under the impression that good mixing monitors are an artful blend of characteristics that may not necessarily be the "best sounding", but which highlight what YOU need to hear to produce a mix that is itself a "best sounding", hopefully while still being non-fatiguing and enjoyable to work with. And obviously that task may be best accomplished by multiple different pairs of speakers, which throw their respective spotlights on different aspects. I'm still working on defining this challenge.
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Post by duke on Jun 21, 2017 0:10:09 GMT -6
In the days of the real studio all had a full range system, even if you mixed on the NS10's you checked your mix on the big speakers. At some point in the project studio regression we put on blinders/ ear plugs and many convinced themselves that the desk top age meant we only needed what fit on the desk! As egos got bigger Studio Monitors got Smaller, yet it's all about that bass and that beat, it's just nobody is listening to what's going on down there! Most real mastering engineers will tell you story after story about projects where nobody knew what was going on below a certain frequency! It's funny to hear something done on 5in speakers in a " studio" playing through a pair of 18's thumpin somebodys Escalade! I can't count the projects I have saved where something the producer/ engineer couldn't hear ate up all their headroom! I laugh every time I see a desktop mastering setup, it seams a number of people got the idea in their collective heads that it would be easier and cheaper to be a mastering engineer and they were qualified because they could get more lowend out of their desktop set up than their freinds. I understand that the economy of what passes for a music industry these days means people work in the environments they have and these are acusticly compromised, but we need a full range check and that falls on the last stage so in my mind you must be able to QC full range if you call your self a mastering engineer! Being able to do this during tracking and mix just makes it easier! Thank you very much Eric for once again taking the time to educate me. I hadn't thought of the sapping effect undetected excess low frequency energy could have on headroom. Excess low frequency energy would hopefully be detected in the tracking stage, is that right?
The people with small rooms who are doing it right - what are they doing? Turning on the subwoofer and using that + mixing monitors? I see several manufacturers of mixing monitors offering matching dedicated subwoofer systems.
I presume you have found that, despite the limited room dimensions of project studios, it still make sense to use something fullrange like B&W 801s for mastering, assuming one can shoehorn them in? Seems to me the midrange voicing "goal posts" might be in a different location for mixing vs mastering monitors (NS10's come to mind, but perhaps that general approach to voicing is the exception these days?).
Speaking of the B&W 801s, what is your opinion of their lower treble region (2.5-5 kHz ballpark)? To my ears that region is a bit over-emphasized, but maybe that's good for a monitor?
Sorry to be tossing out so many questions. Please feel free to ignore some or all.
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Post by duke on Jun 20, 2017 20:54:50 GMT -6
Topshelfmg's “Mastering Monitor Converter Options” thread, along with ericn's posts in that thread, have stirred up questions that have been lurking in the back of my mind for some time.
I can wrap my head around mixing in a project studio, given that fullrange extension is not required.
But my (quite likely flawed) understanding of tracking and mastering requirements is that both normally call for much greater low-frequency extension than mixing typically does. I got this impression from reading books rather than from any first-hand experience on my part, but ericn also mentions it in his replies to topshelfmg.
So my assumption is that tracking and mastering are more demanding as far as low-end extension, and therefore more challenging than mixing, in a small room. Is this correct?
Those of you who do tracking and/or mastering in your project studios, how do you approach monitoring for those jobs?
Thanks!
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Post by duke on Jun 16, 2017 22:32:00 GMT -6
Man some day I'll remember model # meant this puppy 2549 www.voltloudspeakers.co.uk/loudspeakers/b2549-10/My understanding is this is a variation on what was used for years in The bigger REL subs before REL went aluminum cone! Unfortunately my wife says we need to down size so I will lose my workshop space so I won't be doing much speaker development work plus either the Magnepan MG3.5's or the TAD / Augsperger clones are headed for storage 😪 That Volt 2549 looks beautiful and expensive! Four of them would be... even more beautiful... and even more expensive... Thank you for the loaner offer but I'm using a less expensive 10" woofer in my Swarm that still gives me pretty good results.
Sorry to hear you're under pressure to downsize and will lose your workshop space. Workshop space is cheap therapy for us guys. We need to create or we stagnate. This thread is a way for me to keep my creative juices flowing.
I love Maggies, have owned 5 pairs and wanted to become a dealer for them years ago (didn't happen due to a fire). I have admired Augspurgers from afar for many years, but have never actually heard a pair. Imo they look like intelligent designs. I used 10" TAD woofers for a while before that model became unobtainium.
I'd be very interested in whatever you'd like to share about your Augspurger clones!
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Post by duke on Jun 16, 2017 21:19:15 GMT -6
If you have any recommendations for sources that are more focused on home studios than Newell, I'm all ears!! I figure I need to at least read up on the subject before a) launching a barrage of annoying questions here and/or b) starting to build prototype mains.
I'll be testing a candidate subwoofer driver in the next few weeks, but would rather not say what it is just yet.
Still haven't even decided on what configuration to use for the mains yet. The current front-runners are coaxial and MHM (mid-horn-mid). Driver choice will get narrowed down once I think I've figured out where the goal posts are. But price is a consideration, which unfortunately rules out Volts!
My R&D projects tend to stagger along in fits and starts, as I keep having to go back to doing other things that pay the bills.
Finding a real book beyond "put up foam" based on small rooms other than what you have already read is as far as I know nonexistent, realtraps has some good but biased articles on their site. I think the problem is other than the basics of construction rather hard to tame without some study of the actual room and no expert wants to put his name on something that will be taken by many as method rather than a theory! If I end up with an extra 2149 I will try to arrange a loan! Take a look at the new 2in mid ! Would love to try it with A Transducer Labs tweet and a BM220.8 in a Volt 3 way nearfield, ala ATC SCM25! Thank you Eric! I'll spend some time at RealTraps' site - looks like at least one of their videos is aimed in our direction.
What you say about no expert wanting to put his name on "how to treat a home studio room" makes sense, because if Augspurger is correct, apparently individual small rooms tend to have minds of their own.
I see what you mean about that new 2 inch mid. Very nice! Philosophically I lean in a different direction, but if I need to change directions, that mid is high on my list. And I'd hate to outright copy someone else's idea, but your suggestions for woofer and tweeter look really good too!
What's a "2149"?
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Post by duke on Jun 16, 2017 17:17:06 GMT -6
The configuration I normally use for home audio is, a single central amplifier driving four small subs with 10" woofers. Sometimes two amps, for stereo, or for other purposes. (My home audio subwoofer system is called The Swarm, there's some commentary online, but I'd be scaling back the size and cost for home studio). For home studio, one possibility is four small subs with 8" woofers, perhaps measuring 10" (25 cm) square by 21" (53 cm) tall, driven by a two-channel amp. Crown makes one that looks promising. 500 watts total should be more than enough.
The smaller rooms are the bigger challenge, and I'm still in learning mode. Just ordered Philip Newell's book on studio design, reading through Alton Everest's book on Acoustics again... still have a lot of homework to do. I'm starting to think that, in a very small space, fairly directional mains + an unorthodox setup geometry would yield a small geometrical improvement in early reflection path lengths, but whether that translates into a real-world audible improvement is of course unknown at this point.
Thanks for the insights into the family name and temperament! I dimly remember being told as a child how awful the English were, but keep forgetting that I'm supposed to hate them. Don't recall the first name of the original "O'Niell"... but now you've got me curious, I'll see if I can find out. His son (if I recall correctly) settled in Louisiana some time before our Civil War. If family folklore is to be believed, he upheld northern Irish tradition when it came to resolving differences of opinion on local political matters.
Newells book while very informative leans heavily on larger commercial rooms, that is what he built his reputation on. Curious what drivers your thinking for the studio system? If you have any recommendations for sources that are more focused on home studios than Newell, I'm all ears!! I figure I need to at least read up on the subject before a) launching a barrage of annoying questions here and/or b) starting to build prototype mains.
I'll be testing a candidate subwoofer driver in the next few weeks, but would rather not say what it is just yet.
Still haven't even decided on what configuration to use for the mains yet. The current front-runners are coaxial and MHM (mid-horn-mid). Driver choice will get narrowed down once I think I've figured out where the goal posts are. But price is a consideration, which unfortunately rules out Volts!
My R&D projects tend to stagger along in fits and starts, as I keep having to go back to doing other things that pay the bills.
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Post by duke on Jun 16, 2017 13:24:52 GMT -6
Interesting stuff re: directional bass systems, the multi sub system sounds interesting if calibrated. Again my only worry with something like that is space considerations. How many subs would be required for such a system, what sort of power and size? Regarding the idea of a calibrated directional system: think it's a double edged sword - I think guys in tiny edit suits and little bedrooms will be forced to stick with simple 2 way systems. But in rooms where the listener is finding themselves uncomfortably close and has the rear wall space, I would say they would greatly enjoy being able to move back and also the assumed wider sweet spot they would have from this (compared to the about-the-size-of-your-head situations some of these rooms run under). O Neil is a northern name, which fits the hot-blooded element of that story. If you found his name I'm sure I could tell you more. Being a land-league'r or a Unionist was deeply political, geographical and material part of people's lives. A quick wiki says probably Baron William O Neil? There's a line of em up there, Anglo-Irish, and since everyone ever in Ireland is related and presumes relation unto others, I imagine he was getting some flack for sharing the name. They could even be blood related and there could be some disownment involved. You'd be amazed. My grandmother was English, and her father-in-law was an IRA man (actually a Flying Columns member) and was fine with it. Her brother-in-law, however, refused to speak to her. People are nuts. The configuration I normally use for home audio is, a single central amplifier driving four small subs with 10" woofers. Sometimes two amps, for stereo, or for other purposes. (My home audio subwoofer system is called The Swarm, there's some commentary online, but I'd be scaling back the size and cost for home studio). For home studio, one possibility is four small subs with 8" woofers, perhaps measuring 10" (25 cm) square by 21" (53 cm) tall, driven by a two-channel amp. Crown makes one that looks promising. 500 watts total should be more than enough.
The smaller rooms are the bigger challenge, and I'm still in learning mode. Just ordered Philip Newell's book on studio design, reading through Alton Everest's book on Acoustics again... still have a lot of homework to do. I'm starting to think that, in a very small space, fairly directional mains + an unorthodox setup geometry would yield a small geometrical improvement in early reflection path lengths, but whether that translates into a real-world audible improvement is of course unknown at this point.
Thanks for the insights into the family name and temperament! I dimly remember being told as a child how awful the English were, but keep forgetting that I'm supposed to hate them. Don't recall the first name of the original "O'Niell"... but now you've got me curious, I'll see if I can find out. His son (if I recall correctly) settled in Louisiana some time before our Civil War. If family folklore is to be believed, he upheld northern Irish tradition when it came to resolving differences of opinion on local political matters.
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Post by duke on Jun 16, 2017 2:08:15 GMT -6
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The approach I embrace in pursuit of that improvement is somewhat counter-intuitive: Four bass sources (small subwoofers) distributed asymmetrically around the room. Each will inevitably produce a nasty peak-and-dip pattern at the listening position... but each of these nasty peak-and-dip patterns will be different. The sum of all these different peak-and-dip patterns will be significantly smoother than any one alone.
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Just to make sure my point isn't misunderstood, the argument for using multiple subs has to do entirely with quality, not quantity. As for quantity, too much bass is far worse than not enough. But if the quality is there, then the quantity (loudness and bottom-end extension) can be adjusted until it's right for the application.
4 subs as part of the designed solution sounds like it would have some great potential improvements. To realize that potential though, I wonder if the placement guide could be more scientific (and therefore more likely to work) than the usual advice "move them around until it sounds good". As you say, our perception of lower frequencies is not very accurate so it would be difficult for someone to evaluate the "best" solution by ear with 4 moving parts. So some kind of App that gives you a rating and you move them around until the App says this is the best you are getting in this room. I also wouldn't be too worried about eq solutions not having benefits outside the mix position .. in the spaces I am thinking about there is only room enough for one position I do have several sets of guidelines from which people can choose which makes the most sense for them. The general principle is, spread 'em out - don't cluster them. By way of example, here's one approach that I call "Golden Ratio" (based on 1/1.62, which equals .62):
One sub goes in a front corner. The second sub goes .38 times the long wall length away from a corner (not necessarily that one). The third sub goes .24 times the long wall length away from a corner. The fourth sub goes .15 times the long wall length away from a corner. You want to end up with at least one sub somewhere along each of the two walls that are opposite that first corner (the one with the first sub in it). I'd suggest rough-sketching it out first, and remember to avoid clustering. As for where these numbers come from: 1 - .62 = .38; .38 x .62 = .25; and .25 x .62 = .15. Bonus points if you can elevate one of the subs above the midpoint of the room, thus getting good distribution of your bass sources in all three dimensions.
Odds are that one or more of these locations will already be occupied by something that is impractical to move. That's okay - with four low frequency sources, their exact locations are fairly non-critical. Besides, the effective acoustic dimensions of a room are affected by how stiff the room boundaries are as well as whether there are any openings or "soft spots" in them like doors or windows or HVAC vents. So even if you were able to achieve what your tape measure says is dimensional precision in placement, it still will not be acoustic precision at low frequencies.
I don't think I could write an app that can tell you when there is no further room for improvement. But a pink noise source, microphone, and real-time spectrum analyzer will tell you how you are doing.
The distributed multisub system has one more trick up its sleeve (at least my variations on the theme do): By reversing the polarity of one of the subs, we can increase the de-correlation in the bass region, resulting in a closer approximation of the low frequency sound field in a larger room. Every time I've tried reversing the polarity of one sub, the result has been a net improvement. Typically I reverse the polarity on whichever sub is located farthest from the main speakers. This technique also prevents the rise in SPL we'd otherwise get when the wavelengths become longer than twice the smallest room dimension, as the room behavior transitions from modal to pressure zone.
There is one more psychoacoustic benefit from a distributed multisub system I haven't described yet. The ear/brain system tends to "average out" peaks and dips which occur within roughly 1/3 octave of one another. One of the typical problems in small rooms is that the peaks and dips are too far apart at low frequencies for the ear's averaging mechanism to come into play. (At shorter wavelengths we still have plenty of room reflections causing peaks and dips, but eventually as we go up in frequency these peaks and dips get close enough together to effectively form a continuum, by which point they fall well within parameters for the averaging mechanism to do its thing.)
Anyway the distributed multisub approach results in much more numerous peaks and dips, which are smaller and bunched up closer together. This latter characteristic means that the ear/brain system's averaging mechanism can come into play. So the perceptual improvements may be greater than one might expect simply from eyeballing the frequency response curves.
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Post by duke on Jun 15, 2017 22:20:07 GMT -6
Altough it is a pretty funny video, it is also quite accurate to get an idea if you have a problem in this area. It might seem exaggerated. But if it is not really for YOU, well.... . Just to be taken as an easy entrance to the matter if you think you could possibly suffer from ADD/ADHD. Look, a squirrel!!! Lost track of my score pretty quickly but got most of them right, plus I got the squirrel. I did watch it all the way through in one sitting though, only scrolling up and down the page a few times to read other posts, so I should probably have points deducted for that.
It was fun and educational. And a lot of his questions scored a bulls-eye.
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