No, not really, but I too wonder what the whole story is as the bits n' pieces I've read don't make a lot of sense to me...........Quote:
Originally Posted by cradeldorf
GM
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No, not really, but I too wonder what the whole story is as the bits n' pieces I've read don't make a lot of sense to me...........Quote:
Originally Posted by cradeldorf
GM
I've lost track, what cabinets are your drivers residing in now? Got any pictures?
I agree with this, if I eq my 604's like this, the midrange energy overwhelms the lows and some of the highs. Something seems off......Quote:
Originally Posted by GM
Ya think?! ;)
GM
I've got the free WinISD Pro which has an Altec 515-8HHP installed and although I don't know how to use this program and no matter what box or vent size I pick (trial and error), that driver does not plot as well as my 418-8hII. With both the 418 in an 8 cu ft box and 11X3 sq in vent or 416-8A in an A7-500, I have the EQ boosted at the very bottom and top only and both sound great (music content only, no video).?? :)
?? Sorry, I miss your point.
GM
LOL. Sorry for the ramble, I didn't know anything about the 515's and thus the 604's and after playing around, I was concurring with the above statements that the 515 and all Altecs for that matter need EQ at the top and bottom of the frequency spectrum.
Not sure I agree with 'all' unless limited to the systems designed for a high output impedance since speakers with 411s, etc. designed for SS amps generally don't need any bass boost in a typical HIFI/HT app. WRT the HF, if CD horn EQ is used, the highs generally don't need boosting either.
GM
OK, I retract everything I wrote. My only experience with Altec has been the A7's, 418/32B thingy?s, and a quad of 421/511B powered PA thingy?s, but it has been a 35 year long and lovely journey. :)
Speaker Testing and Analysis
This was at the top of a web search page.
I was giving this situation some thought last night and I have a theory. However, if you like the way they sound now maybe you don't need this theory after all!Quote:
Originally Posted by cradeldorf
Quote:
Originally Posted by juniper
I was thinking that you've been doing a lot of crossover changes/customizations etc. (swapping out inductors, resistors, capacitors, etc.) and cabinet changes trying to find the crossover and cabinet design that sounds the best with your 604's. However, you've been doing these modifications and listening tests (to audibly evaluate which mods sound best) with very unconventional graphic equalizer settings. So your current crossover and cabinet design that you're using is customized to be the one that sounds best with your (very) unusual graphic equalizer settings.Quote:
Originally Posted by GM
IMHO, if you really want to get the most from your Altecs, I would recommend doing your crossover and cabinet mods/experimentation/ and listening evaluations (to assess your results) with the graphic equalizer and tone controls set flat or at least with much less graphic EQ/tone controls (if you just can't listen to them completely flat under any circumstances)--a very subtle smiley face graphic EQ setup (which is a much more conventional setting/probably much more appropriate for 604's) would still be a huge improvement as far as being appropriate for your listening evaluations during crossover and cabinet experimentation/modifications. With your graphic EQ and tone controls set flat (or at least close to flat), you're modifying your crossovers and cabinets (via listening tests/trial and error) to sound the best with your speakers, and not modifying your crossovers and cabinets to sound the best with your unusual graphic EQ settings. Once you find which crossover and cabinet design sounds best with your speakers, then you can add some EQ to sweeten/fine tune the sound further if needed.
I know you've done a lot of work on your crossovers and different cabinets and I'm basically asking you to revisit it (and maybe drive Parts Express crazy), but if you want the most out of your speakers I think it's worth it and IMHO you're likely to be very pleasantly surprised by the results. Does this suggestion make sense to anyone else here?
Yes, heaps of sense. I'm one of those geeks who mainly uses EQ in "when all else fails" situations. So, i'm buyin what yer sellin.Quote:
Does this suggestion make sense to anyone else here?
If i might make a suggestion to you VOT, break large bodies of text in your posts up into spaced paragraphs, it makes it much easier for us old farts with failing eyes to read, and more importantly makes it much faster to go back and parse certain parts of the text to be sure we fully understand what you mean.
Thanks, bowtie. I just went back and edited it/broke it into three paragraphs instead of one huge one and yes, it's a lot easier to read that way.Quote:
Originally Posted by bowtie427ss
I think that even people who always use EQ and never listen flat would benefit from doing crossover and cabinet mods/experimentation (and subsequent listening evaluations) with a flat (or almost flat if they find flat unbearable!) EQ setting and after finding what sounds the best with their speakers, then use an equalizer/season to taste.....Quote:
Originally Posted by bowtie427ss
It still appears that your main use of these speakers is for video playback and I would have to EQ for that scene in a similar fashion as your EQ picture. Video sucks and you will probably never get it right, and when you are done, will have ruined the sound of your speakers for audio listening. With out true 5.1 surround sound, your are just chasing demons. Set your speakers for what they are designed for, stereo audio listening, and suffer through the sound affects and poor engineering of video.Quote:
Originally Posted by cradeldorf
I agree that video sound quality often times isn't up to snuff with a well recorded and mastered musical studio recording (vinyl/CD's), but I've found that many movies from this century actually have relatively good sound quality. So, VH, we may have to agree to disagree on this point. I do, however, agree with your main point "Set your speakers for what they are designed for, stereo audio listening...."Quote:
Originally Posted by VolvoHeretic
I have my Model 19's and Model 14's optimized for listening to music (CD's and Vinyl). I've got the dual crossover pots on the speakers etc. ( and I do (sparingly) use a graphic equalizer) dialed in to where (well recorded and mastered) music sounds phenomenal on them. With them setup this way, many "modern" Blue Ray movies/DVD's and even many stereo Satellite TV broadcasts (and digital cable broadcasts before I dumped Time Warner) sound great on them with no changes made to the dual crossover pots or equalizer settings. In fact, that's how I judge how good I consider the sound quality of a DVD or cable/satellite broadcast to be. If it sounds great on my stereo system in my customary/default EQ settings that I use to listen to music, then I consider that movie/tv broadcast to have "good" sound......
My wife and I watched the movie "Avatar" (the movie Cradeldorf uses in his clip in this thread) on satellite TV though the Model 19's with my customary/default (for music) EQ settings and it sounded very good--no mods to my EQ settings or dual crossover pots on the speakers were needed. I think they did a good job regarding the sound quality for that movie, even if they should have been sued by Roger Dean for mimicking his artwork/landscapes! ;)
A FEW EXAMPLES OF ROGER DEAN'S ART
http://www.hostboard.com/forums/hbmc...2012/08/37.jpg
http://www.hostboard.com/forums/hbmc...2012/08/38.jpg
http://www.hostboard.com/forums/hbmc...2012/08/39.jpg
http://www.hostboard.com/forums/hbmc...2012/08/40.jpg
http://www.hostboard.com/forums/hbmc...2012/08/41.jpg
CD, here's what I'd do if it were me:
1) Get a measurement rig (either have someone come over who has one, or you can put one together - a "turnkey" option is the Omnimic, but you can put together your own rig for less than half the price of that).
2) As VOTT suggests, take everything in the signal path, write it all down, and build a test plan that allows for understanding what each component is doing to the measurements. For example,
* start with raw drivers (free air impedance sweeps),
* then add in the cabinets (cabinet loaded impedance sweeps),
* then add in the amp with no EQ or crossover (raw driver FR measurements)
* then add in the crossover
and so on. Time consuming, yes. But fun, and only with that methodical approach can you get down to the nitty gritty of how all the pieces are changing the sound.
3) If you can't get hold of a FR measurement rig, you can still go through the steps in #2 with listening tests and get some value from it, and at a minimum you'd probably want to keep a "listening journal" of sort to be able to keep track of everything as more of the system components get layered in.
just my 2?
I visited his video link, and barring that tad bit of echoey-ness (which was due to the room while doing the recording), to be frank, the sound was almost normal, and this confirms that the speakers are alright. Also around 10 months back, he had started a thread about how to reduce the "shouty-ness" of his 604s :) which is again a normal thing in the case of the 604s.
So it seems that the speakers are okay, and the problem is somewhere else in the audio chain, most probably with the 5.1 splitter.
Yup Dave (VOTT),this is good advice....... :wink2:Quote:
Originally Posted by bowtie427ss
Yes, I've had one for years and it works great. Let us know if you have any problems.
Good stuff, right there, I don't care who you are... :)Quote:
Originally Posted by cradeldorf
This is good work :cool2:.
The second reading seems to be nearer.
When are you going to measure up the 'C's ?
Um, that would be me. :) I would build a couple of wood rings and epoxy them to the inside of the cut end of the barrel halves so that they don't fall apart when you start shaking them. I'ts going to take a lot of glue to hold them together, although, if they work out nicely, I would fiberglass up the insides into one strong solid mass.
Edit: I mean a hollow ring at the open end and a solid one at the closed end where you are going to cut in the speaker to hold the multi-piece lid together (I think that it is multi piece) and then cut out the speaker hole out through both the lid and the reinforcing ring. Kind of hard to describe without pictures. :)
Glad I made sence CD. The fiberglass would be for the inside. If it where me, I would have the outside sandblasted, wood and metal, then stain if so inclined and then clear coat for a nice rustic weathered look. Brushed or 36 grit coarse sanded with the wood grain would look better, but I don't know how you could get it uniformly even with the metal rings in place.
For some unknown reason, these specs don't quite jive, i.e. Sd, Cms, Mmd, BL, Re won't calculate the listed Fs, Vas, Qts, though 'in the ballpark' for general comparison and basic cab alignments.Quote:
Originally Posted by aditya
GM
Be sure and offset the driver some golden or acoustic ratio as a circular baffle has the highest amplitude eigenmodes of any shape.Quote:
Originally Posted by cradeldorf
GM
Don't see the Vas for the Es. The C has stiffened up a bit as Fs is high and Vas low, which I imagine is due to the spider, though sometimes the surround goop can too. Acetone will loosen the latter up, but unless GPA knows a trick or two, might be SOL on the spider.Quote:
Originally Posted by cradeldorf
GM
GM, what's with the "Golden Rule"? Is the inside of my speaker doing the same thing as the inside of my listening room with nulls, nodes, voids, and/or standing waves (and evidently eigenmodes) being created by the sound waves bouncing back and forth off of the top/bottom, side/side and front/back panels and you don't want the speaker positioned in the dead center of the front baffle and having any frequencies canceled out? :)
Correct, the cab is a miniature building both inside and outside, so adheres to the same acoustical physics. Note that peaks/nulls can't be cancelled out, only averaged out by shifting them to many more smaller amplitude ones that will in turn decay away more rapidly due to being lower in energy.
Inside the cab can be damped of course, but always best to keep it to a minimum IME, so while using an offset is primarily for the exterior, you 'kill two birds with one stone'.
Making as many different path-lengths to the various boundaries as practical does this. A circle with a sound source dead center will radiate in a virtually infinite number of peaks/nulls all at the same frequencies, so with a large baffle this can be quite audible as they comb filter with the driver's output.
GM
Yes GM, the BL data particularly seems to be in what unit, W/M ? Re seems to be the Zmin at around 11 ohms, at around 400 HZ, and not the usual Rdc. Cms, and piston dia seems to be ok. I accepted Qts at the specified value of .264, and after playing around got the BL at 21.48 N/A. Vas, Le and Fs stayed the same. 'n' is also pretty close.Quote:
Originally Posted by GM
Actually these readings were taken at around the same time when Thiele's papers were published in the AES journals, and I am sure but not able to recollect now, that these measurements were taken either by Thiele himself or somebody pretty well known in the industry. I am still searching for the source where I had found it.
Put the piston dia at 12.58 inch. And repeat the Vas measurements with different weights, and note the results. Choose weights to shift Fs between 15% to 40%, and note the changes in the readings. It takes some effort to get the correct data for Vas.Quote:
Originally Posted by cradeldorf
Also take a 'in-box' impedance reading. This will help.
Thanks GM, I never thought about considering the outside of the box as an issue. I guess my idea of a spherical concrete orb sub is not a great idea? :)
My notes are gone, but I want to say weber/meter, but I find no such conversion nor newton/amp for that matter.Quote:
Originally Posted by aditya
'n' ? what's this?
It was a Prof. Ashley and I got them from the late Bill Eckle via the local Altec distributor way before the WWW became available to the masses and is still available on his website in memorium: ASHLEY
GM
You're welcome!Quote:
Originally Posted by VolvoHeretic
This is a whole different 'kettle of fish'! 'Sound is Round', so if sound is radiating around a sphere, there are no eigenmodes in its size pass-band and even these are radiating away at such a steep angle, they dissipate very quickly, so little chance of comb filtering with the driver's output.
The driver of course is flat, relatively speaking, so it will have these strong eigenmodes if some sort of deflection or damping ring isn't used like is seen on some 'FR' drivers.
Harry Olson's early measurements shows how various shapes affect dispersion:
GM
edit: Hmm, looks like the forum rescaled them to uselessness. Do I need to post them elsewhere or did I miss something in uploading them?
Cool! Thanks!
GM
Quote:
Originally Posted by GM
Yes....weber/meter it is, used to be used earlier. 'Newton-per-Amp' is the same as 'Tesla-meter'. But I had just plugged a standard value to try the driver out, and finally found a value which had made the sim-ing work.
By 'n' I meant 'eta', for efficiency.;)
Another 'yes' for you as usual, for the info about the source of the t/s parameters. Many thanks.
Regards
Aditya
Yeah when measuring the VAS piston area (cone/dust cap) will always be in cubic inches.So when trying to figure the correct data to enter you are essentially trying to figure the total piston area in cubic inches.. And adding the correct weight does take some effort..Quote:
Originally Posted by aditya
VAS methods
1. Added Mass
2.Known Box
Measuring Loudspeaker Driver Parameters
Quote:
Originally Posted by Altec Best
Hi AB,
I think it is a typo....area in cubic inches ?
Probabely you were talking about the "Known box" method, where the space (cubic inches) in the spkr front is also added to the known volume box in consideration.
Actually Cradeldorf is doing it in the open-air fashion... for the time being probabely.
CD,
you can put the cursor on the graph at the frequency you want, and this little box will pop up showing the the precise impedance at that frequency.
