TH-18 Flat to 35hz! (Xoc1's design) - Page 113 - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 2nd October 2012, 02:36 PM   #1121
Nissep is offline Nissep  Sweden
diyAudio Member
 
Join Date: Aug 2011
On the topic of amplifiers.

Have you seen these post over at avs?
Lab Gruppen FP14000 clone amplifiers

WOAH, it's official, the FP10000Q has audiophile-quality top end (this is a BIG DEAL!!!)

Nice to have some cheap power if you want to make your 18sw115 move some air..
  Reply With Quote
Old 2nd October 2012, 03:04 PM   #1122
epa is offline epa  Netherlands
diyAudio Member
 
Join Date: Apr 2010
Location: amsterdam
power doesn't say it all,like art says
here is a topic about an amp shootout.
__________________
one good thing about music ,when it hit you feel no pain.
so hit me with music
.
  Reply With Quote
Old 2nd October 2012, 04:09 PM   #1123
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by SonicXtasy View Post
Will this cab (driver dependent) play the bass in these songs?

Anyway that gets me to how much power can I run on a 15 amp ckt? I have run both PLX3602's close to clipping (one 4ohm stereo and one 8 ohm bridged) and a PLX2402 about half power (4 ohm stereo) from a 15 amp ckt but the voltage drop was pretty low and the sub amp did "brown out" at extreme levels as Art mentioned.

Dave
Dave,

The XOC1TH-18 does fine to about 35 Hz, and can still be EQed to just above 30 Hz.
Most bass has as much first harmonic as fundamental, so you will "hear" 16 or 20 Hz tones when the cabinet plays the 32 Hz or 40 Hz harmonic. That does not happen with many (most) DJ kind of "subs" , which come in at 50 Hz.

There is no "k" in circuit , but a 15 amp circuit in good shape can provide an average of 1800 watts.

As mwmkravchenko pointed out, most breakers can withstand short peaks of 10 times their rating.

Getting back to the average rating of 1800 watts, let us say your squashed compressed bass heavy music has only 10 dB dynamic range (2 dB less crest factor than pink noise), you could potentially run 100% efficient amps capable of 18,000 watt peaks on a single 15 amp circuit without exceeding the average power rating of the 15 amp circuit.
Amps are usually in the 60-85% efficiency range, subtract peak power of your particular amp combination efficiency rating.

In the real world, a 15 amp circuit can legally (in at least some jurisdictions) be run using 14 AWG wiring.
So what is the voltage drop of 18,000 watts (150 amps at 120 volts) on 150 feet of 14 AWG?

Voltage Drop Calculator

Oops, the voltage has dropped to only 51.6 volts on those peaks, not good, kick drum fans.

However, if that same 15 amp circuit wired with 14 AWG was located just under the main breaker box, totaling only 4 feet of wire (2 feet out from the hot breaker, two feet back to neutral) the voltage would hardly drop at all- 118.2 volts would be the minimum with 150 amp draw.

Breakers are subject to wearing out, and some are not up to spec to start with, I once had a batch of 20 Amp Square D breakers (normally a very good brand) that would trip when a single amplifier was turned on.

Breaker sensitivity, what other stuff may be plugged in to the same circuit (12 amp coffee makers, lights, random microwave use, etc.) coupled with type of music, length and gauge of wire, and amplifier efficiency, make it impossible to give a “one size fits all” answer to your question.

That said, always best to plug in your own 12 or 10 AWG cords as close to the main breaker box as possible if you want to get the most dynamics out of your system.

Art Welter
  Reply With Quote
Old 2nd October 2012, 05:46 PM   #1124
diyAudio Member
 
Join Date: Feb 2010
Location: Tampa bay, FL
Thanks for the info Art. I figured there wasn't a "standard" answer but that gets me some basic understanding. It means I could run a PLX3602 on highs and something as big as the I-Tech 8000 that neo dan was talking about, both at 4 ohn stereo, at reasonable volume with compressed bass and considerably higher with dynamic "music" before tripping a 15 amp breaker as long as it is the only thing on that circuit and the wire length/gauge are ok.




Quote:
Originally Posted by weltersys View Post

There is no "k" in circuit

Art Welter
Sorry, I work for the local phone company and unless its a POTS (plain old telephone service) line we refer to it as a ckt (circuit)

Last edited by SonicXtasy; 2nd October 2012 at 06:15 PM. Reason: Mis-quote
  Reply With Quote
Old 2nd October 2012, 07:12 PM   #1125
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by SonicXtasy View Post
Thanks for the info Art. I figured there wasn't a "standard" answer but that gets me some basic understanding. It means I could run a PLX3602 on highs and something as big as the I-Tech 8000 that neo dan was talking about, both at 4 ohn stereo, at reasonable volume with compressed bass and considerably higher with dynamic "music" before tripping a 15 amp breaker as long as it is the only thing on that circuit and the wire length/gauge are ok.
And the breaker is good, and your "music" has less average power than "1/8th power pink noise", usually not a problem with live music, but for some reason (massive clipping at every gain stage cough cough), often not the case for recorded music run by many DJs .

As you can see, the I-T 8000 will draw 35.1 amps if you lean on it at 4 ohms.

The QSC PLX 3602 alone will draw 40 amps at 120V with a full power sine wave signal (for around one second before tripping it's own breaker), but "only" 11.5 amps at 1/8th power pink noise, and 19.5 amps 1/3 power pink noise at 4 ohms.

But again, with a single stiff 20 amp 120 VAC line, I have run two PLX 3602 and four Crest CA-9, all with clip lights flashing from time to time.

All depends on the "music".

Art
Attached Images
File Type: png PowerDraw..png (117.1 KB, 526 views)
  Reply With Quote
Old 3rd October 2012, 12:59 AM   #1126
NEO Dan is offline NEO Dan  United States
diyAudio Member
 
NEO Dan's Avatar
 
Join Date: Jun 2008
Location: N.E. Ohio
Quote:
Originally Posted by CRESCENDO View Post
SO... REW on my Mac=
Yeah that about sums it up...
Make the built in sound the default input device and ditch the FW box entirely or only use it for output and mic preamp duty, route the mic signal back to the Mac through the mic/headphone jack. You could even just use the SPL meter if it has a 1/8" output, you'll probably need a mono cable though.
__________________
Regards,
Dan

Last edited by NEO Dan; 3rd October 2012 at 01:09 AM.
  Reply With Quote
Old 9th October 2012, 12:26 AM   #1127
diyAudio Member
 
Join Date: Nov 2006
How accurate is the Hornresponse max spl response? I'm using xmax and rms figures, and most drivers are displacement limited below 60hz at high power.
  Reply With Quote
Old 9th October 2012, 12:29 AM   #1128
NEO Dan is offline NEO Dan  United States
diyAudio Member
 
NEO Dan's Avatar
 
Join Date: Jun 2008
Location: N.E. Ohio
Quote:
Originally Posted by bubblersound View Post
How accurate is the Hornresponse max spl response? I'm using xmax and rms figures, and most drivers are displacement limited below 60hz at high power.
Sounds correct since maximum excursion occurs ~45-50Hz for the drivers I've looked at. What were you expecting?
__________________
Regards,
Dan
  Reply With Quote
Old 9th October 2012, 01:27 AM   #1129
diyAudio Member
 
Join Date: Dec 2009
Location: California
The spl to displacement figures may be quite accurate, but the fact I like to remember is that real world compression (dynamic and thermal) affect both. In other words, the spl and displacement in hornresp may be achieved in real life, but at a higher input voltage. There's quite a bit of info regarding compression types and how they affect output in this thread.
  Reply With Quote
Old 9th October 2012, 09:39 AM   #1130
diyAudio Member
 
Join Date: Nov 2006
Quote:
Originally Posted by CRESCENDO View Post
The spl to displacement figures may be quite accurate, but the fact I like to remember is that real world compression (dynamic and thermal) affect both.
That's what I was pondering.
Then we have cone correction to help control excursion. And peak displacement which is usually more than xmax.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
18 inch labhorn design. mulletdude Subwoofers 23 27th November 2013 08:43 PM
Ciare 18 bass horn design soundhead Subwoofers 5 22nd September 2013 08:33 AM
2 18 bass design simpleacoustic Subwoofers 101 15th May 2011 09:22 AM
I want my Avalanche 18 to go flat to 15hz thadman Subwoofers 10 11th November 2006 02:54 AM
Looking for suggestions on a 1300W Dual 18 sub design. mjcohen Subwoofers 5 21st December 2004 07:38 AM


New To Site? Need Help?

All times are GMT. The time now is 03:38 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2