Post by: Antone Atmarama Bajor on December 01, 2006, 08:07:04 PM
Just wondering what happened to the car subwoofer thread???
I know its not PA (Public Adress/Pro Audio)
But it did involve using "PA" Drivers. Antone-
Post by: Craig Leerman on December 01, 2006, 09:41:46 PM
There are plenty of car audio sites around the web.
Post by: Michael 'Bink' Knowles on December 01, 2006, 09:43:59 PM
-Bink
Post by: Bennett Prescott on December 01, 2006, 10:05:39 PM
Post by: Elliot Thompson on December 02, 2006, 12:34:30 AM
Post by: Antone Atmarama Bajor on December 02, 2006, 03:42:48 PM
But almost none of the Car Sub forum people know anything about in cab gain.
Most of the people working at car audio places don't know anything about it either.
I want to know more about predicting room or cab gain.
You just go ahead and climb around the walls and ceiling see what I care.
Antone-
Post by: Mark "Bass Pig" Weiss on December 09, 2006, 01:12:26 AM
Post by: David Little on December 09, 2006, 06:56:34 PM
| Antone Atmarama Bajor wrote on Sat, 02 December 2006 15:42 |
... But almost none of the Car Sub forum people know anything about in cab gain. Most of the people working at car audio places don't know anything about it either. I want to know more about predicting room or cab gain. Antone- |
Antone,
Get a copy of Winspeakerz
http://www.trueaudio.com
It will calculate cabin gain for a given enclosure. http://www.trueaudio.com/about_5.htm#Automobile%20Modeling
Post by: Andy Peters on December 10, 2006, 05:14:06 AM
| Mark "Bass Pig" Weiss wrote on Fri, 08 December 2006 23:12 |
What always gets me about the car sub folks is their de facto procedure of inflating SPL figures. 179dB from 4 18" drivers? C'mon, get real. |
I think they simply add the SPL numbers from each speaker together.
You know, each speaker does 44.5 dB by itself, so four times 44.5 dB is ...
-a
Post by: Mark "Bass Pig" Weiss on December 12, 2006, 02:38:49 AM
| Andy Peters wrote on Sun, 10 December 2006 05:14 | ||
I think they simply add the SPL numbers from each speaker together. You know, each speaker does 44.5 dB by itself, so four times 44.5 dB is ... -a |
Lol! That must be it!
Post by: Christian Effendy on January 26, 2007, 08:27:41 AM
A single 'normal' 12" sub driver that's only have around 90dB SPL in free space, can have 20Hz SPL at 100dB in car with proper enclosure and placement.
When the room is very small and the pressure is very high, you can have an incredible SPL numbers.
Try this with an SPL meter:
Crank your pro 2x18 sub in free field, then do the same thing in your house. Notice the added SPL in bass region?
Want more? Play it in a small, concrete basement.
Post by: Mike Butler (media) on January 27, 2007, 10:41:27 AM
| Christian Effendy wrote on Fri, 26 January 2007 08:27 |
That's cabin gain, boys. Well, and with very large amount of power and excursion too. A single 'normal' 12" sub driver that's only have around 90dB SPL in free space, can have 20Hz SPL at 100dB in car with proper enclosure and placement. When the room is very small and the pressure is very high, you can have an incredible SPL numbers. Try this with an SPL meter: Crank your pro 2x18 sub in free field, then do the same thing in your house. Notice the added SPL in bass region? Want more? Play it in a small, concrete basement. |
Post by: Mark Sadhra on January 27, 2007, 07:18:30 PM
| Mark "Bass Pig" Weiss wrote on Sat, 09 December 2006 00:12 |
What always gets me about the car sub folks is their de facto procedure of inflating SPL figures. 179dB from 4 18" drivers? C'mon, get real. |
Their is nothing wrong with those numbers, but you have to understand that the vehicles they use are purposely built,reinforced with cement and re bar and the subs are fed 10s of thousands of watts for a few seconds just long enough to get a reading.
Take a look at the current world records 176.6db's with one sub.
http://www.termpro.com/asp/worldrecords2.asp
The meter used for measurements: http://www.termpro.com/storefront/index.asp?Page=1
also check out the forums on www.termpro.com for more info.
Post by: Mark "Bass Pig" Weiss on January 30, 2007, 12:50:24 AM
Here's the video link:
http://www.youtube.com/watch?v=9wAxPwh5bF0
However, it looks suspicious for the following reasons:
Look at the guy leaving the store. Now most of us have seen windows shake like that when the door slams. The timing of the window shake, just a couple seconds before the guy passes by is awfully suspect.
If it were really that possible to produce enough infrasound to shake the windows from 20' away like that, then the guy would be doubling over and vomiting on himself, or perhaps would avoid walking in that direction altogether. At the very least, he'd be putting his hands over his ears in a hurry as that soundblast occurs. He didn't react at all, which is suspicious. I think the audio was dubbed in later, or the whole video was shot at a time when they KNEW a customer would be leaving the store.
OTOH, if 4 RE 18" drivers COULD do that, then i reckon 4 Bassmaxx ZR18s would have broken all the store windows.
Post by: Mark Sadhra on January 30, 2007, 05:54:25 AM
| Mark "Bass Pig" Weiss wrote on Mon, 29 January 2007 23:50 |
There's a video reposted on YouTube, from Realm of Excursion, OTOH, if 4 RE 18" drivers COULD do that, then i reckon 4 Bassmaxx ZR18s would have broken all the store windows. |
http://www.youtube.com/watch?v=lxScxOaAuzY
check out some hair tricks.
http://www.youtube.com/watch?v=lxScxOaAuzY
Post by: Mike {AB} Butler on January 30, 2007, 09:04:16 AM
Mark understands deep bass reproduction probably better than you and I put together (read down to posts below).
Now to my point:
Sure, there have been windows blown out of cars. Remember that the cubic air volume of a car is very small.. compared to that of a store. Unless they set up the speakers right at the store windows, the chances of that much movement diminish rapidly, as sound decreases in energy level over distance. You cannot get the same energy at 50' as you get at 4'.. without an exponential jump in accoustical output.
Point is, the two events compared here (interior of a car and the interior of a store) are NOT one and the same.
Regards,
Post by: Mark Sadhra on January 30, 2007, 03:40:19 PM
| Mike {AB} Butler wrote on Tue, 30 January 2007 08:04 |
Mark, Mark understands deep bass reproduction probably better than you and I put together (read down to posts below). Now to my point: Sure, there have been windows blown out of cars. Remember that the cubic air volume of a car is very small.. compared to that of a store. Unless they set up the speakers right at the store windows, the chances of that much movement diminish rapidly, as sound decreases in energy level over distance. You cannot get the same energy at 50' as you get at 4'.. without an exponential jump in accoustical output. Point is, the two events compared here (interior of a car and the interior of a store) are NOT one and the same. Regards, |
I understand but claiming that if the RE's can shake windows, Bassmaxx subs would shatter the windows is wrong. SPL has way more to do with the install than equipment used. I bet it's around 90% install 10% equipment.
Post by: Mike {AB} Butler on January 30, 2007, 06:06:30 PM
| Mark Sadhra wrote on Tue, 30 January 2007 15:40 |
I understand but claiming that if the RE's can shake windows, Bassmaxx subs would shatter the windows is wrong. SPL has way more to do with the install than equipment used. I bet it's around 90% install 10% equipment. |
What does that have to do with your previous statement? Nothing, as far as I read:
(Quote:)
Mark "Bass Pig" Weiss wrote on Mon, 29 January 2007 23:50
There's a video reposted on YouTube, from Realm of Excursion,
OTOH, if 4 RE 18" drivers COULD do that, then i reckon 4 Bassmaxx ZR18s would have broken all the store windows.
Your response:
I know automotive windshields break @ 160 plus db's.
http://www.youtube.com/watch?v=lxScxOaAuzY
check out some hair tricks.
http://www.youtube.com/watch?v=lxScxOaAuzY
(end Quote)
What I understood from Mark Weiss's comments is that the whole concept originally put forth by the automotive poster in response to a PA thread is absurd. I would tend to agree. And your barging into this thread with what I consider to be [unrelated to the rest of the thread] "defense" of the automotive sound industry so far has produced little to do with real physics, science, or even practical application to the very real issues in live audio. The problems in achieving high SPL in a car are far fewer than trying to do so at 120' in a venue. Sure, SOME expert setup figures into the equation for any kind of setup.. but power is still power - a system is either innately big enough.. or it is not. THAT's all Mark Weiss is alluding to - in a very polite manner.
Please, take the automotive stuff out of this discussion, and return to the basics of drivers that produce the best performance for cost..
Thanks,
Post by: Mark "Bass Pig" Weiss on January 30, 2007, 09:48:51 PM
My intent was to question the accuracy of the video clip (I suspect that the author took advantage of the off-camera door slamming shut, which typically, with those aluminum-framed storefronts, causes all the glass to set off in a subsonic oscillation.
For something 20+' away from the building to achieve that, it would require massive output below 10Hz, so massive, in fact, that anyone walking in the viscinity of the sound source (that non-chalant man, for instance) would be instantly in pain, or at the very least, badly startled in the same way as if a car bomb had gone off just 10' from him. Since the man had clearly just exited the store, and appeared undisturbed by these sounds, I conclude that the cause of the window shake would likely NOT have been from the auto sound system.
Equipment is equipment, a system is a system. Auto systems are rediculously inefficient with tiny sealed boxes. A large, vented box with a Hemholtz resonator tuned to 10Hz might be believeable, but not sealed boxes with drivers that are clipping badly.
YouTube is full of smoke and mirrors tricks. When I'm bored on my coffee break, I frequently load YouTube and search "subwoofer" to see the latest laughs. I've seen every one of these videos. If these people only knew how silly most of them look.
Post by: Mark Sadhra on January 31, 2007, 05:37:56 AM
| Mark "Bass Pig" Weiss wrote on Tue, 30 January 2007 20:48 |
Gentlemen: \ Auto systems are rediculously inefficient with tiny sealed boxes. A large, vented box with a Hemholtz resonator tuned to 10Hz might be believeable, but not sealed boxes with drivers that are clipping badly. |
Why does it require massive output at 10hz? most SPL systems are tuned around 50hz.Spl systems don't use small sealed boxes they use very large ported boxes tuned high. Take a look at the link below. Thats a install log of a system similar to the one in the viseo. Same subs 4000 watts more power.
http://fresnoracing.ipbhost.com/index.php?showtopic=30159
Post by: Mike {AB} Butler on January 31, 2007, 07:21:20 AM
Good points on the rest of your post.However, it's clear that this guy is going to keep on trying to post in something other than scientific terms.
Regards,
Post by: Mark "Bass Pig" Weiss on January 31, 2007, 03:04:07 PM
| Mark Sadhra wrote on Wed, 31 January 2007 05:37 |
Why does it require massive output at 10hz? most SPL systems are tuned around 50hz.Spl systems don't use small sealed boxes they use very large ported boxes tuned high. Take a look at the link below. Thats a install log of a system similar to the one in the viseo. Same subs 4000 watts more power. http://fresnoracing.ipbhost.com/index.php?showtopic=30159 |
Mark,
Because sound at 50Hz doesn't cause a slow movement of objects like we see in the video. That glass was moving at resonance, which is more like 2-3 Hz. 50hz output won't excite an object that's resonant at 2Hz. The initial wavefront would have to be of infrasonic range, with a very large change in barometric pressure.
I think that Steve Meade Designs is using the video as a marketing stunt, with a large helping of deception thrown in.
Thanks for pointing out the construction link. The photos were enjoyable to view. Nice construction technique with the threaded steel rods. Although 34.5Hz is not a very low tuning frequency. I tend to consider 30Hz to be more in the midbass range, than deep bass. (After listening to 10Hz test signals all afternoon, even 20Hz seems almost like treble to my ears.)
Post by: steve meade on March 01, 2007, 02:28:30 PM
| Mark "Bass Pig" Weiss wrote on Mon, 29 January 2007 21:50 |
There's a video reposted on YouTube, from Realm of Excursion, claiming to be shaking the windows on some storefront. Here's the video link: http://www.youtube.com/watch?v=9wAxPwh5bF0 However, it looks suspicious for the following reasons: Look at the guy leaving the store. Now most of us have seen windows shake like that when the door slams. The timing of the window shake, just a couple seconds before the guy passes by is awfully suspect. If it were really that possible to produce enough infrasound to shake the windows from 20' away like that, then the guy would be doubling over and vomiting on himself, or perhaps would avoid walking in that direction altogether. At the very least, he'd be putting his hands over his ears in a hurry as that soundblast occurs. He didn't react at all, which is suspicious. I think the audio was dubbed in later, or the whole video was shot at a time when they KNEW a customer would be leaving the store. OTOH, if 4 RE 18" drivers COULD do that, then i reckon 4 Bassmaxx ZR18s would have broken all the store windows. |
i love it when someone who APPEARS to be much smarter then me, and probably is, makes a STUPID comment like this. No it wasnt staged, it was real. Every video ive ever done is real. You can examine it all you want but those windows are not shaking because someone opened up a door LOL. My system is 100% without a doubt flexing those windows. Dont let the distortion (due to the digital cam not being able to take the bass) fool you.....ive spent as much if not MORE time on my RTA as i have on my SPL sensor. It actually sounds pretty good for being capable of that kind of sound pressure.
Please, do me a favor, go to my site and look at my other videos. Do some research on just what i have in my Tahoe before you make comments that make you look "not so smart".
OTOH, if 4 RE 18" drivers COULD do that, then i reckon 4 Bassmaxx ZR18s would have broken all the store windows.
Nice comment....i "reckon" that your wrong. Those ZRS look ok for what you guys are doing but for what I AM DOING, those things dont want ANY of my old RE MT's NOR my Current Fi BTL subs.
Also, about this being a "marketing stunt"......what am i marketing? My site is just for fun and basicly a journal of everything about me and the things i do.....i dont really sell anything. I work for a commercial roofing company im not even "technically" in the industry. Im in it just for fun and i dont profit off of anything unless you count my sponsorships. Free gear i guess is profit but no hand-over-fist cash making here. Just fun.
Thanks for over examining my stuff though. Might want to re-evaluate.
Regards,
Steve Meade.
www.stevemeadedesigns.com
Post by: steve meade on March 01, 2007, 03:06:49 PM
just playin...anyway i wouldnt mind coming around here and learning some home audio expertise from you guys since im interested in that field. I gotta say though when it comes to the car enviroment some of you guys should be taking notes and not coming to conclusions without having the facts.....the same way I SHOULD before popping off at the jaws about what YOU guys are doing.
Post by: Andy Peters on March 01, 2007, 07:13:01 PM
| steve meade wrote on Thu, 01 March 2007 13:06 |
just playin...anyway i wouldnt mind coming around here and learning some home audio expertise from you guys since im interested in that field. |
This is not the Home Audio Board. While most of us here have decent enough home stereo systems (and hopefully, large record collections to go with that system), we don't discuss home stereo stuff here. There are plenty of other forums where one can discuss the finer points of home theatre set-ups.
| Quote: |
I gotta say though when it comes to the car enviroment some of you guys should be taking notes and not coming to conclusions without having the facts.....the same way I SHOULD before popping off at the jaws about what YOU guys are doing. |
Here's a conclusion: systems designed to simulate a nuclear explosion in the back of a Scion xB are not audio systems. It may be interesting, in a very weird and ickily-masturbatory way, to generate a 190 dB SPL tone burst for a hundred milliseconds, but that skill (and the techniques and equipment used to do it) isn't useful when the task is to present high-quality music program material to a large audience.
-a
Post by: steve meade on March 01, 2007, 10:54:24 PM
Post by: Andy Peters on March 02, 2007, 03:27:26 AM
| steve meade wrote on Thu, 01 March 2007 20:54 |
i drive a Tahoe not a Scion thanks |
... so otherwise, my observation is true?
-a
Post by: Mike {AB} Butler on March 02, 2007, 07:33:13 AM
Regards,
Post by: Mac Kerr on March 02, 2007, 10:51:46 AM
| Antone Atmarama Bajor wrote on Fri, 01 December 2006 20:07 |
Just wondering what happened to the car subwoofer thread??? I know its not PA (Public Adress/Pro Audio) But it did involve using "PA" Drivers. Antone- |
Mac
moderator
Post by: Mac Kerr on March 02, 2007, 10:57:23 AM
Mac
moderator