Way over-the-top 2-way 2 channel system build-thread. - AVS Forum | Home Theater Discussions And Reviews
Baselworld is only a few weeks away. Getting the latest news is easy, Click Here for info on how to join the Watchuseek.com newsletter list. Follow our team for updates featuring event coverage, new product unveilings, watch industry news & more!


Forum Jump: 
 19Likes
Reply
Thread Tools
post #1 of 93 Old 05-26-2015, 07:39 PM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Way over-the-top 2-way 2 channel system build-thread.

Here's some teaser pictures:
http://imgur.com/a/aTcER

Not going to list hardware right away, it won't make sense nor be entertaining to read a list, I'll let you know as we go.
The enclosure shown is an open prototype used for testing purposes. Had 2x31 band EQ to limit low frequency excursion instead of enclosure tuning resistance. Only have done preliminary testing so far, but I had to set up the microphone on a microphone stand and leave the room for some of the tests because this is so loud. And that was only 1 speaker, not two. With only one EP4000 amp, not three.
Suffices to say this build will involve some really fun hardware. The white and green ruler on the picture is a 30cm ruler for scale. Ignore fish-eye lens effect on camera.
You may say "well, how loud can a single compression driver and a 15" midbass really be?". Well, these pdf's show you the frequency responses of these drivers.
Compression driver and midbass driver.
Note that the compression driver response is with a 90x40 waveguide, I am using a 60x40 waveguide.
It must be said that I won't use these completely unfiltered, I have a proper EQ and mic so will be smoothing out the response. Will also be using an active crossover of course, building a 1700w passive filter would be a tall order.

I have heard good pro grade drivers and decided then I wanted to build a stereo based on similar drivers. But I was very skeptical about these pro grade drivers, unknown territory and all. But the suspension rigidity on these things and the power of the motors just make them magnificent. Just have one prototype open enclosure and I have found myself listening to it for many many hours already, just with half the sound of every song (with just 1 amp I have only been able to have one channel of the stereo sound going to one 2-way speaker. Will be picking up two more amps today). I have studied the drivers I have and the design is very optimal in scale of everything compared to everything else. And no cost has gone into aesthetics or anything else that do not involve creating as much sound as possible at the least possible audible distortion for the given amount of money. I will be hiding these behind a white speaker grill fabric so the looks of these is completely irrelevant, by the way.
I am trying to avoid commonly used completely pointless words for describing the auditory experience that these drivers give. Effortless, I think, fits best. Effortless reproduction of sound at reference sound levels (100db or more). Its as though, they're just talking, and you look at the db meter and see triple digits. I have not been able to stop grinning since I got this prototype test enclosure "finished". I almost can't pull myself away from it to continue the build.

Its so strange to measure low single digit volts on the speakers and seeing triple digit db. I have to check a fifth time before i dare posting any measurements, it feels like I have done something wrong in the measurement technique.

Last edited by ronny31; 06-06-2015 at 06:57 PM.
ronny31 is offline  
Sponsored Links
Advertisement
 
post #2 of 93 Old 05-26-2015, 08:08 PM
Member
 
PorkchopExpr3ss's Avatar
 
Join Date: Sep 2014
Location: Gods waiting room.(Boca Raton)
Posts: 157
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 68 Post(s)
Liked: 32
nothing is over the top in this forum section.........lol. nice build, lets see some graphs
Boomassiv likes this.
PorkchopExpr3ss is offline  
post #3 of 93 Old 05-26-2015, 08:24 PM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Quote:
Originally Posted by PorkchopExpr3ss View Post
nothing is over the top in this forum section.........lol. nice build, lets see some graphs
Weather seems nice today, sunny, no wind, may be able to do an outdoor test today, we'll see. Indoor tests are nice for EQ-ing but echoes make the distortion figures inaccurate.
Any preferred measurements you would be particularly interested in? off axis? distances? volume level? Length of sweep in seconds? pink noise? white noise? brown noise?
ronny31 is offline  
post #4 of 93 Old 05-26-2015, 08:46 PM
AVS Special Member
 
Face2's Avatar
 
Join Date: Mar 2007
Location: Long Island, NY
Posts: 1,057
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 186 Post(s)
Liked: 125
Quote:
Originally Posted by PorkchopExpr3ss View Post
nothing is over the top in this forum section.........lol. nice build, lets see some graphs
Must be his first time reading or posting in this section.
Erich H and Boomassiv like this.
Face2 is online now  
post #5 of 93 Old 05-26-2015, 08:52 PM
AVS Special Member
 
auburnu008's Avatar
 
Join Date: Jun 2004
Location: Auburn, AL
Posts: 1,473
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 335 Post(s)
Liked: 339
I was coming to post the same thing the others did. This section of the forum is bad for your wallet.
Boomassiv likes this.
auburnu008 is offline  
post #6 of 93 Old 05-27-2015, 03:56 AM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Yeah, picked up some more stuff from the post office, so this:

For a 2-channel 2-way system.
ronny31 is offline  
post #7 of 93 Old 05-27-2015, 05:38 AM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 18,353
Mentioned: 79 Post(s)
Tagged: 0 Thread(s)
Quoted: 1284 Post(s)
Liked: 1593
two words for you: protective capacitor. :-)
Torkild and Bombelman like this.

Listen. It's All Good.
LTD02 is online now  
post #8 of 93 Old 05-28-2015, 06:17 AM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Well, here's some indoor measurements, primarily to give an idea of response in an open enclosure and distortion. First a loud measurement. REW thinks its about 7db under what the db meter says with 1khz test tone, and REW says 1khz is 106db. Have like 55db noise floor with two EP4000s running so to get any meaningful distortion figures I had to put the volume quite high. To do that I had to start at a high frequency (70hz in this case), or the excursion could be dangerous on the 15" drivers. Test distance is 1 meter, haven't measured what wattage I had at this measurement. Microphone has a very flat response and can go up to 130db, and is connected via a Profire 2626 external soundcard with phantom power through XLR cables. Amps are fed with XLR via a 2x31 band EQ from the 2626, but the EQ was set at +/-0db across the board at green and pink line (pink is shown further down).

No idea where the mouse cursor was when I took the picture, the THD isn't the average across the spectrum. Across the spectrum the THD varies from about 0.5% to a peak of about 6.6% (those bumps at the low end of the spectrum). Don't know how to get a picture with the average THD figures.

This shows the frequency response. The highest line is the loud test in the first picture, the pink line is the un-equalized measurement at a few db short of reference level (again, REW thinks its less loud due to not thinking to calibrate the mic gain setting before the tests, and not going to take new ones today).
The blue line is the response after some light EQ-ing with the 2x31 band EQ, only to drop the high portions between 100hz and 400hz. 1/48 octave smoothing.
Here's 1/6 octave smoothing:

Could probably fix the "bump" at 100-400hz by simply jumping up the gain on the horn a couple db. Crossover is at 1khz, there the 15" hands over the frequency spectrum to the compression driver. Just used a mark 1 ear to decide the current horn amp voltage gain relative to the 15". The 15" is maxed out of course.

Now I'm going to listen to some music, sweeps are exciting indeed but the 1khz song and the 20-20khz song gets old.

EDIT: Actually, the loud measurement also has the small EQ change to lower that bump between 100 and 400hz. No change in the shape of the bump was made though.

Last edited by ronny31; 05-29-2015 at 04:14 AM.
ronny31 is offline  
post #9 of 93 Old 05-28-2015, 11:40 AM
AVS Addicted Member
 
Mfusick's Avatar
 
Join Date: Aug 2002
Location: Western MA
Posts: 28,992
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 491 Post(s)
Liked: 1858
Nothing is too much for this forum you'll fit right in
Mfusick is online now  
post #10 of 93 Old 05-29-2015, 06:00 AM
AVS Special Member
 
Jay1's Avatar
 
Join Date: Aug 2002
Location: West Valley, AZ
Posts: 4,525
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 231 Post(s)
Liked: 215
Quote:
Originally Posted by ronny31 View Post
Well, here's some indoor measurements, primarily to give an idea of response in an open enclosure and distortion. First a loud measurement. REW thinks its about 7db under what the db meter says with 1khz test tone, and REW says 1khz is 106db. Have like 55db noise floor with two EP4000s running so to get any meaningful distortion figures I had to put the volume quite high. To do that I had to start at a high frequency (70hz in this case), or the excursion could be dangerous on the 15" drivers. Test distance is 1 meter, haven't measured what wattage I had at this measurement. Microphone has a very flat response and can go up to 130db, and is connected via a Profire 2626 external soundcard with phantom power through XLR cables. Amps are fed with XLR via a 2x31 band EQ from the 2626, but the EQ was set at +/-0db across the board at green and pink line (pink is shown further down).

No idea where the mouse cursor was when I took the picture, the THD isn't the average across the spectrum. Across the spectrum the THD varies from about 0.5% to a peak of about 6.6% (those bumps at the low end of the spectrum). Don't know how to get a picture with the average THD figures.

This shows the frequency response. The highest line is the loud test in the first picture, the pink line is the un-equalized measurement at a few db short of reference level (again, REW thinks its less loud due to not thinking to calibrate the mic gain setting before the tests, and not going to take new ones today).
The blue line is the response after some light EQ-ing with the 2x31 band EQ, only to drop the high portions between 100hz and 400hz. 1/48 octave smoothing.
Here's 1/6 octave smoothing:

Could probably fix the "bump" at 100-400hz by simply jumping up the gain on the horn a couple db. Crossover is at 1khz, there the 15" hands over the frequency spectrum to the compression driver. Just used a mark 1 ear to decide the current horn amp voltage gain relative to the 15". The 15" is maxed out of course.

Now I'm going to listen to some music, sweeps are exciting indeed but the 1khz song and the 20-20khz song gets old.

EDIT: Actually, the loud measurement also has the small EQ change to lower that bump between 100 and 400hz. No change in the shape of the bump was made though.

You need to adjust the scale of your graph. 20db is huge, the typical standard for useful comparison is 5db. It looks like there is about a 15db difference between 150hz and 10khz, but your scale makes it look fairly smooth and flat. You could also adjust the min/max to something like 60db and 120db.
artsci2 likes this.
Jay1 is offline  
post #11 of 93 Old 05-29-2015, 07:05 AM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Quote:
Originally Posted by Jay1 View Post
You need to adjust the scale of your graph. 20db is huge, the typical standard for useful comparison is 5db. It looks like there is about a 15db difference between 150hz and 10khz, but your scale makes it look fairly smooth and flat. You could also adjust the min/max to something like 60db and 120db.
My scale was chosen because it was what it happened to be after I had zoomed in and out a hundred times on various bits.
What I need to do is have tons of smoothing, that's the typical standard. This is a typical response for this design and size compression driver without smoothing. Will post better graphs as we go however.

It does need some proper EQ across the frequency band, but that was expected. Will be dropping the response across the board to a flat response. No boosting the dips, because if there's a dip of 3db somewhere, that's due to the base sensitivity of the driver, not the input voltage to the driver. If I then give it 3db boost at that frequency and listen to music at rms, then happen to have music with that frequency then the power will be 3db above rms (double the rms).
ronny31 is offline  
post #12 of 93 Old 05-29-2015, 07:25 AM
Senior Member
 
Nate Hansen's Avatar
 
Join Date: Aug 2012
Location: Rochester, MN
Posts: 405
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked: 97
I think Jay meant typical standard for diyers to compare. Manufacturers will do whatever they can to make garbage look pretty.
Nate Hansen is offline  
post #13 of 93 Old 05-29-2015, 07:58 AM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Quote:
Originally Posted by Nate Hansen View Post
I think Jay meant typical standard for diyers to compare. Manufacturers will do whatever they can to make garbage look pretty.
These are only preliminary tests, only for satisfying some curiosity (mostly mine). I thought the comparison between the graphs with different smoothing would be the most interesting bit. Didn't really think about the scaling other than that.
ronny31 is offline  
post #14 of 93 Old 05-29-2015, 08:55 AM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 18,353
Mentioned: 79 Post(s)
Tagged: 0 Thread(s)
Quoted: 1284 Post(s)
Liked: 1593
what freq and slopes are you using for your crossover?

Listen. It's All Good.
LTD02 is online now  
post #15 of 93 Old 05-29-2015, 12:24 PM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Quote:
Originally Posted by LTD02 View Post
what freq and slopes are you using for your crossover?
Linkwitz-Riley 12dB/Octave filters - According to the spec sheet on the active crossover. Set to 1khz.
ronny31 is offline  
post #16 of 93 Old 05-29-2015, 01:31 PM
Senior Member
 
Nate Hansen's Avatar
 
Join Date: Aug 2012
Location: Rochester, MN
Posts: 405
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked: 97
What active xo are you using?
Nate Hansen is offline  
post #17 of 93 Old 05-30-2015, 03:06 AM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Quote:
Originally Posted by Nate Hansen View Post
What active xo are you using?
Alto X34SW. Got it for nothing.
ronny31 is offline  
post #18 of 93 Old 06-02-2015, 04:03 PM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
I have done some sloooow sweeps to listen to the audibility of the sensitivity differences, have been getting some interesting results. I invite others to do the same.
ronny31 is offline  
post #19 of 93 Old 06-02-2015, 05:06 PM
AVS Special Member
 
A9X-308's Avatar
 
Join Date: Mar 2008
Location: Australia
Posts: 5,961
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 451 Post(s)
Liked: 291
The title of the thread is a misnomer: I don't see how it is anywhere near OTT, rather pretty typical for around here.
Bombelman likes this.
A9X-308 is offline  
post #20 of 93 Old 06-03-2015, 02:47 AM
Senior Member
 
Nate Hansen's Avatar
 
Join Date: Aug 2012
Location: Rochester, MN
Posts: 405
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked: 97
Audibility of sensitivity differences........huh?
Nate Hansen is offline  
post #21 of 93 Old 06-03-2015, 08:37 AM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Quote:
Originally Posted by A9X-308 View Post
The title of the thread is a misnomer: I don't see how it is anywhere near OTT, rather pretty typical for around here.
Each compression driver will put out 132.8 at rated RMS output (drops off above around 13khz). The mids will each put out over 133db between 70hz and 1khz at rated AES power output. All db figures at 3 feet. Please do let me know if anyone here are using louder compression horns and mids. I REALLY want to read their build threads.
With 2 of each of these speakers placed within 3 feet of the listener it will be around 136db sustained output. That's 32 times more sustained energy output than the threshold of pain (if threshold of pain is 121db). To put it another way, that's 36 Klipsch R-28F floorstanding speakers in a 3 foot radius circle around you, each given 150w rms power.

I'm building slowly but surely, been having a Norwegian summer. Closed off some mountain roads because of snow and so forth. The usual.

Quote:
Originally Posted by Nate Hansen View Post
Audibility of sensitivity differences........huh?
Yeah, if a speaker says 10db difference in sensitivity between two frequencies its interesting to see how audible that is. I don't want to skew how audible you think it is by saying how audible I think it is.
ronny31 is offline  
post #22 of 93 Old 06-03-2015, 10:00 AM
Senior Member
 
Nate Hansen's Avatar
 
Join Date: Aug 2012
Location: Rochester, MN
Posts: 405
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked: 97
Might be a bit of a language barrier here 😉

Are you talking in room or anechoic response?
Nate Hansen is offline  
post #23 of 93 Old 06-03-2015, 10:32 AM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Quote:
Originally Posted by Nate Hansen View Post
Might be a bit of a language barrier here 😉

Are you talking in room or anechoic response?
The theoretical output is in open area, no reflections (aka anechoic chamber). I think its more that you compare bass db with these numbers and think "that's not that loud". But 130db in bass is quite low, two 10" subwoofers easily reach 140db in cars, yet its completely comfortable to listen to that. But 130db with mids and highs; its scary. Its the sort of stuff you would use to destroy the world if your address is in a hollowed out volcano. 120db really is the threshold of pain in those frequencies. You would be mad to stand within 20 feet of these at max sustained power levels (its 119.6db at 20 feet, and 105.6db at 100 feet). But that's the fun thing about this You would be mad to drive at the top speed that a Koenigsegg One:One can do, but if you have one you CAN do it if you were to befell a sudden bout of madness and that's exciting
ronny31 is offline  
post #24 of 93 Old 06-03-2015, 10:48 AM
AVS Addicted Member
 
Stereodude's Avatar
 
Join Date: Jan 2002
Location: Detroit Metro Area
Posts: 11,903
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 1723 Post(s)
Liked: 1108
I'd rather have quality sound than volume, but that's just me. And I know a think or two about volume with a set of Seaton Sound Catalyst 12Cs.
Stereodude is offline  
post #25 of 93 Old 06-03-2015, 04:34 PM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Quote:
Originally Posted by Stereodude View Post
I'd rather have quality sound than volume, but that's just me. And I know a think or two about volume with a set of Seaton Sound Catalyst 12Cs.
I'd rather have both. A choir singing at full chaff, an entire orchestra of instruments and you're sitting front row. All reproduced by two pairs of voice coils. Those voice coils need to be able to produce some hefty sound to sound good. If what they can produce is 36 times greater volume than the next thing you compare them to then they have to work 36 times less hard at it.
I hope you listen to Beethoven's ninth symphony on your 12Cs. Symphonies are so much fun on LOUD setups. The entire thing isn't 110db, but the loud bits are that loud, so you need 110db at the listening position to get the full symphony experience from front row. This isn't a bad recording:
Boomassiv likes this.
ronny31 is offline  
post #26 of 93 Old 06-03-2015, 07:27 PM
AVS Special Member
 
A9X-308's Avatar
 
Join Date: Mar 2008
Location: Australia
Posts: 5,961
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 451 Post(s)
Liked: 291
Quote:
Originally Posted by ronny31 View Post
Each compression driver will put out 132.8 at rated RMS output (drops off above around 13khz). The mids will each put out over 133db between 70hz and 1khz at rated AES power output. All db figures at 3 feet.
Big deal. Theoretical SPLs based upon thermal ratings are worthless, but are a typical newb mistake. In my experience P Audio overrates both their sensitivity and power handling and thermal compression will rip several dB off that. Your distortion figures don't look all that great at 106dB so they're going to be miserable at much higher levels.

Quote:
Originally Posted by ronny31 View Post
Please do let me know if anyone here are using louder compression horns and mids.
Why? Are you doing this to get a big number or for high SQ?

Quote:
Originally Posted by ronny31 View Post
With 2 of each of these speakers placed within 3 feet of the listener it will be around 136db sustained output. That's 32 times more sustained energy output than the threshold of pain (if threshold of pain is 121db). To put it another way, that's 36 Klipsch R-28F floorstanding speakers in a 3 foot radius circle around you, each given 150w rms power.
Thanks, but I've been doing this for a long time with systems much bigger than yours in larger rooms, so I know how to run basic calculations.

I stand by my earlier comment that this is not much different to many of the other 15+horn/WG systems out there.
A9X-308 is offline  
post #27 of 93 Old 06-03-2015, 07:49 PM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 18,353
Mentioned: 79 Post(s)
Tagged: 0 Thread(s)
Quoted: 1284 Post(s)
Liked: 1593
96 db sensitivity @1w1m and 1700 watts rms power handling.
amps bridged will output about 1800 or so watts.
at that level, power compression will be 2-3db after a little "warm up" :-)


so 96 + 10*log(1700/1) - 3 = 96 + 32.5 - 3 = 125.5 dB SPL.
with two speakers (add about 3db) and in a room (add some more), total SPL should be up near 130dB or so.


that's assuming a relatively high tuned cab so excursion limits aren't exceeded otherwise SPL will be lower (potentially much lower).


in any case, that is plenty for mid/top spl.


what are you planning for the bass?

Listen. It's All Good.
LTD02 is online now  
post #28 of 93 Old 06-03-2015, 07:50 PM
AVS Special Member
 
notnyt's Avatar
 
Join Date: Dec 2008
Location: Long Island, NY
Posts: 5,676
Mentioned: 60 Post(s)
Tagged: 0 Thread(s)
Quoted: 944 Post(s)
Liked: 889
notnyt is offline  
post #29 of 93 Old 06-04-2015, 08:52 AM - Thread Starter
Advanced Member
 
Join Date: Mar 2015
Location: Norway
Posts: 536
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 276 Post(s)
Liked: 43
Quote:
Originally Posted by A9X-308 View Post
Big deal. Theoretical SPLs based upon thermal ratings are worthless, but are a typical newb mistake. In my experience P Audio overrates both their sensitivity and power handling and thermal compression will rip several dB off that. Your distortion figures don't look all that great at 106dB so they're going to be miserable at much higher levels."
At the power levels I got 106db in REW I measured 113db with 1khz test note with db-meter (forgot to calibrate REW to the db-meter before the test). So the scale is 7db below actual scale.
"several db". For the wattage given X volts to be half (-3db) due to heating the resistance have to be doubled, to get that in copper the temperature needs to be 300 degrees C. Do you have any data that would suggest speaker voice coils reach this temperature at RMS/AES?
"miserable at much higher levels." - Yeah... miserable compared to what? Please provide some un-smoothed measurements from what you would consier good speakers.

Quote:
Originally Posted by A9X-308 View Post
Why? Are you doing this to get a big number or for high SQ?
I am doing this because these drivers sound good. And they're exciting.

Quote:
Originally Posted by A9X-308 View Post
Thanks, but I've been doing this for a long time with systems much bigger than yours in larger rooms, so I know how to run basic calculations.

I stand by my earlier comment that this is not much different to many of the other 15+horn/WG systems out there.
Well excuse me for calling it over the top then, don't be so butt-hurt about it. This isn't a size contest of a certain sort. If every person on Earth had a stereo that could give permanent hearing damage in 5 seconds it would still be over the top and I hope it would still be exciting then. I wish people to share in the excitement. I could just as easily build this and never show any of you, my value from this build not be diminished. I took that decision long ago, because I know no normal people will be impressed by a stereo so that can't be the reason I build one.

PS: Bigger, probably. These will be approximately 1.2 by 1.5 by 2 feet. Yet the sound power of 36 three foot tall floorstanders. That's the point.

Quote:
Originally Posted by LTD02 View Post
96 db sensitivity @1w1m and 1700 watts rms power handling.
amps bridged will output about 1800 or so watts.
at that level, power compression will be 2-3db after a little "warm up" :-)


so 96 + 10*log(1700/1) - 3 = 96 + 32.5 - 3 = 125.5 dB SPL.
with two speakers (add about 3db) and in a room (add some more), total SPL should be up near 130dB or so.


that's assuming a relatively high tuned cab so excursion limits aren't exceeded otherwise SPL will be lower (potentially much lower).


in any case, that is plenty for mid/top spl.


what are you planning for the bass?
The response between 70hz and 1khz is over 100db at 1w/m. Correct my math with correct math. Also, -3db thermal loss means 300C on the voice coil (that's when resistance is double that of 20C resistance), I rather doubt that's reached, but one day if I have the town to myself I would really like to test AES levels for 2 hours and measure the resistance (hence, measuring temperature of the voice coil). Until then I can't really be sure how much the thermal loss is, but 300 degrees C is hotter than most voice coil glue can take as far as I know. Not to mention if 300C is reached current is halved so the temperature should drop to an equilibrium before that, unless the voltage is high enough for the equilibrium to be 300C, in which case the true voltage given to the speakers is way above AES rating.
I'll be using these as lows until 1khz with EQ to limit low down excursion for now. Lower voltage signal at the low end with EQ means lower voltage on low frequencies from amp which means lower excursion, acts like a high enclosure tune only you can change it without a hand saw. But eventually I'll upgrade with some proper subwoofers to take over the duty below 70hz. Until then I can manage with this. At low power levels I don't require any low frequency EQ protection, at single digit watts the drivers can handle any frequency without reaching excursion limits. Anyway, audibility of low frequencies is so low that a lot of music don't suffer from having a falloff at the low end. Still feel the chest kick from the 1812 Overture even though I'm lacking the 20-60hz to some degree.

Quote:
Originally Posted by notnyt View Post
yawn

distortion numbers not looking too good.. huge rolloff on the high end.
Yawn? I am still eagerly waiting for your epic fronts measured with no smoothing. Lets have a distortion rock-off!
I happen to know these compression drivers have the same distortion figures as most other similar compression horns, the limits are usually the limits of the diaphragm material itself so being the same material across many drivers its extremely similar distortion figures.
The smallest possible detectable amount of light is the difference between 50 candles of light and 51 candles, about 2%. I don't know what the smallest possible detectable audible difference of distortion is among lets say 100db sound. If we had 0.01% THD on a 100db soundtrack and increased distortion to 2% THD, would we notice in a double blind experiment? I would love to actually get my hands on some papers regarding this. I know many really expensive speakers don't even show the distortion figures for some reason (at least I have problems tracking down distortion figures especially unsmoothed from the cream of the crop of speakers).

The original compression drivers I ordered were smaller diameter diaphragm with 1" diameter throat, which had much flatter response and higher extension over 13khz. But they didn't have 2 of them in storage so I got some more expensive larger compression horns instead at no extra cost. I was given the choice to wait for the ones I originally wanted instead, but I went with the more expensive ones. Over 13khz the perceived volume goes up anyways (until you can't hear it at all).
I don't listen to many instruments that go way over 13khz either. Because not many instruments go over that.
I wouldn't take this chart completely literal to the exact hertz on everything, but its certainly in the right ballpark with most of this: http://www.independentrecording.net/...in_display.htm

Please do provide some unsmoothed distortion figures, if you bother (directed at everyone here who bothers). Lets compare some speakers of different "grades". And please provide any papers on the audibility of distortion, if you happen to know of any or find any.

EDIT: Why can I be excited for the epic stereos of others yet others seem to not be doing the same? Not a single female is present in this entire forum, no one will be impressed by your nonchalant reaction.

Last edited by ronny31; 06-04-2015 at 08:58 AM.
ronny31 is offline  
post #30 of 93 Old 06-04-2015, 10:00 AM
Senior Member
 
Nate Hansen's Avatar
 
Join Date: Aug 2012
Location: Rochester, MN
Posts: 405
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked: 97
I think many have concluded that thd by itself is meaningless. You might try searching for Earl Geddes' paper on distortion.
ronny31 likes this.
Nate Hansen is offline  
Sponsored Links
Advertisement
 
Reply DIY Speakers and Subs



Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off