My multi location subwoofer thread inspired by Welti,Devantier,Geddes !!! - Page 4 - AVS Forum
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post #91 of 191 Old 03-10-2012, 03:06 PM - Thread Starter
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I just snapped and ordered the MiniDSP, Dayton plate amp, and Dayton 12" sub driver.....
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post #92 of 191 Old 03-14-2012, 05:04 PM - Thread Starter
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here is the new location for sub #2. Here are the two subs.....





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post #93 of 191 Old 03-14-2012, 06:21 PM
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Are those DIY diffusion devices in the background?
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post #94 of 191 Old 03-15-2012, 01:34 AM - Thread Starter
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Are those DIY diffusion devices in the background?

Yup. Not quite by the book, but they do diffuse. They are totally random depth from 1" to 7", incriments are totally random, which makes them not quite by the book.... but i like them
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post #95 of 191 Old 03-31-2012, 04:50 AM - Thread Starter
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Well, the new system is up and running after some issues. First issue was the massive hum out of the main subwoofer system once i hooked up the MiniDSP.
After doing some postings and reading i ended up doing a chassis ground from the Mini to the outlet it was plugged into. That was a perfect fix, totally silent !!!

The AUX subs were a different story. Only way i could get them to quiet down was ground isolators from Ratshack. They are not free from the hum as the mains, but unaudible from the LP...

The fit and finish of the new subs makes them look like they have been in the room for ever

Now, on to the MiniDSP. What a slick piece of gear this thing is. I have to say it has everything i will need to accomplish this project.....

First off my main quad 15 system has huge room gain/cabin gain. A simple Low shelf filter brought me level with about 5.5db of gain. I had to add a PEQ filter to bring down a little peak and that was it. That took all of ten minutes LOL.

The AUX subs required a little more work. They were filling in quite a dip in the response above 40hz. That dip or depression was straight across the LP. Since i needed nothing out of them below 40hz i decided to use a HiPass filter to increase their handling ability and not mess up the nice response i was getting out of the mains from 40hz down. I wanted to low pass them, but it reacted with the response too much, so i decided to let the LFE do its work at 120hz. Once that was done i was able to increase their gain to fill in the null and it worked perfect. The second AUX sub was calibrated the same way, but for some acoustical reason 25hz hipass was the best i could do without it messing with the main response graph at 40zh and above.

This little MiniDSP is a damn sweet piece of gear. I will be leaving it powered all the time as well as the AUX subs. Terrible turn on thump ! Besides that it is, and has been the perfect solution to my Welti and Devantier flat response subwoofer system !!!!!

The OmniMic is also perfect for this project, with both screens minimized i was manning the helm like a real pro, building filters and making changes on the fly like a had a brain in my head or some thing. Between the OmniMic and MiniDSP i have to say they get a Five Star rating. The Advanced 4way plugin for $10 bucks is laughable when you think about it, $10 bucks and you get all this power. I am smiling ear to ear.

I have to thank Marcus over in the Audyssey forum for continuing to harp on the findings of Welti and Devantier, thanx buddy !!!!
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post #96 of 191 Old 03-31-2012, 07:30 AM
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Originally Posted by kgveteran View Post

Well, the new system is up and running after some issues. First issue was the massive hum out of the main subwoofer system once i hooked up the MiniDSP.
After doing some postings and reading i ended up doing a chassis ground from the Mini to the outlet it was plugged into. That was a perfect fix, totally silent !!!

Where exactly did you ground to on the MiniDSP? I've got a little hum on my MiniDSP/MiniDigi combo. I've grounded the enclosure and the power supply, but I don't see any place obvious to ground the MiniDSP itself....

thanks
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post #97 of 191 Old 03-31-2012, 09:44 AM - Thread Starter
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Originally Posted by josephjcole View Post

Where exactly did you ground to on the MiniDSP? I've got a little hum on my MiniDSP/MiniDigi combo. I've grounded the enclosure and the power supply, but I don't see any place obvious to ground the MiniDSP itself....

thanks

Center screw on the outlet cover, to the chassis of the Mini. i scraped off a little powdercoating to make contact with the aluminum under it on the mini
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post #98 of 191 Old 03-31-2012, 08:06 PM
 
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This is a great build. Inspirational. Can't wait to go diy.
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post #99 of 191 Old 03-31-2012, 08:55 PM
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Originally Posted by kgveteran View Post

This little MiniDSP is a damn sweet piece of gear. I will be leaving it powered all the time as well as the AUX subs. Terrible turn on thump

Turn on the MD, then a couple of seconds later, the subs. If the MD is what's creating the thumps, this will solve it.
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post #100 of 191 Old 04-01-2012, 04:28 AM - Thread Starter
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I readjusted my amp delay turn on's and it went on as silent as could be, when i turned off the system..... It sounded like a plane hit my house hahahahaha. I'm just gonna leave it on...

I watched BattleLA, due to its over the top bass and the jury is still out on placing subs near field. The reponse is totally Killer, there is absolutly no doubt about multiples providing a flat response, and no doubt to the Mini's ability to deliver the goods... I'm just not use to hearing the sub....

I will leave it be for now, but i think more needs to be done with regards to Lopassing them at 80hz and giving them a very narrow window. I'm also wondering is my system could have used 15's instead of 12's, or better yet 15's and a pro amp.....or down firing. I really think its all in the XO ! I heard that before.....

There's a nice Rap version in Dispicable Me in the beginning that i remember sounded very different with the new subs, i remember it sounded better before. I have to keep in mind i never really heard a flat response before, i never had strong 40hz-80hz at the LP. This may be grounds for a little house curve and building a true bandpass instead of just a Hipass....
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post #101 of 191 Old 04-02-2012, 11:55 AM - Thread Starter
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I watched the animated movie "9", which is a BR DTS HD. I have to say the 12's were having some issues keeping up with the dynamics of my system.

My first reaction to some serious SPL's is that i should have made sealed 15's and used a pro amp. Regardless of the narrow band at which they operate at, i need bigger drivers. They need to be down firing also.

WTS, i will ease back off the throttle for now and enjoy the new balance of sound i have, which is the same across my LP.

But, the method of multiple subs and mode canceling is rock steady and is so worthwhile to seek out......

....and spread the word, these will be for sale soon.... Long throw 15's and a EP2500 would be the choice next time. No disrepect to the Daytons, they never failed at all ! I just feel they are on the doorstep, and before they do i may need to move on....
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post #102 of 191 Old 04-07-2012, 05:03 PM - Thread Starter
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So, i tried to hipass and lopass to try and narrow the band so the 12's could try to keep up.....it aint workin....

So, what 15's am I looking at that have some serious Xmax so they can do the job. These are up for sale ! You would think that filling in a narrow gap like i needed would have been do with ease using 12's but i guess not.

I turned off the AUX subs are rewatched "9" with just the quad Tumults and they are some pretty heavy hitters.

So, what should i expect to get out of these subs when they are up for sale, and what drivers will i buy with the proceeds

One more option to concider if you would like to chime in, and that would be to split up the four Tumults and rearrange them in four separate locations. Do you think i would lose that huge impact i get with them colocated up front like i have them now....
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post #103 of 191 Old 04-09-2012, 12:02 PM - Thread Starter
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Just more rantings..... I bought War Horse on BR. I thought the movie was great. I decided that i wouldnt be building anything soon, so i would back off the AUX subs so i dont damage them. So, I back off the input gain on the plate amps, and lo and behold..... The movie sounded awesome. The 12's were happy with the new level setting.... So, like a good tweaker i began to raise it to see where they would begin to show signs of stress. I then backed the gain a little and continued with the movie.

Later that night i ran some sweeps to see where i was in my graph world. Seems the hole i filled in all but about -5db. I will now begin a slow build and enjoy the subs as they are. They filled in quite nice.....

The experment was still a success as multiples is the way to go.
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post #104 of 191 Old 04-09-2012, 12:21 PM
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Quote:
Originally Posted by kgveteran View Post

Just more rantings..... I bought War Horse on BR. I thought the movie was great. I decided that i wouldnt be building anything soon, so i would back off the AUX subs so i dont damage them. So, I back off the input gain on the plate amps, and lo and behold..... The movie sounded awesome. The 12's were happy with the new level setting.... So, like a good tweaker i began to raise it to see where they would begin to show signs of stress. I then backed the gain a little and continued with the movie.

Later that night i ran some sweeps to see where i was in my graph world. Seems the hole i filled in all but about -5db. I will now begin a slow build and enjoy the subs as they are. They filled in quite nice.....

The experment was still a success as multiples is the way to go.

He there KG,
I've enjoyed your thread so far...it's been fun to watch you experiment. From what I've read from the multisub approach (at least Geddes's version), the sub nearest to you should be barely audible. It's only there to fill out the frequency response. Not sure exactly how your room is set up, maybe you could combine your 2 Dayton's into one larger sub, and pick up one (or 2)more to be the "3rd" sub in the Geddes arrangement.
It sure doesn't sound like you are very far off. Have fun!
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post #105 of 191 Old 04-09-2012, 12:28 PM
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Quote:
Originally Posted by kgveteran View Post

Just more rantings..... I bought War Horse on BR. I thought the movie was great. I decided that i wouldnt be building anything soon, so i would back off the AUX subs so i dont damage them. So, I back off the input gain on the plate amps, and lo and behold..... The movie sounded awesome. The 12's were happy with the new level setting.... So, like a good tweaker i began to raise it to see where they would begin to show signs of stress. I then backed the gain a little and continued with the movie.

Later that night i ran some sweeps to see where i was in my graph world. Seems the hole i filled in all but about -5db. I will now begin a slow build and enjoy the subs as they are. They filled in quite nice.....

The experment was still a success as multiples is the way to go.

That means you filled the hole in by ~15dB!!!! That, my friend, is known as SUCCESS.

Final graphs?

JSS
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post #106 of 191 Old 04-09-2012, 02:08 PM
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KG-

I haven't been following your thread, but I think you are finally doing it right and that is why you are getting good results. Those Dayton's definitely can't keep up with your mains if you try to play them at full tilt. I would have suggested something completely different if that was the intended use.

I would suggest re-working your eq now that you have it setup as a more inline with Geddes methods. You might also try moving the LP XO point up a bit. Basically make it as high as you can go without having localization issues. Modal smoothing from 80-120hz is very beneficial. It is vital that the smoothing/aux sub is only playing at a fraction of the level of your primary subs.

Did you ever separate your 4 15's into two separate boxes? That would yield even further improvements as you could place one box in a corner and another mid-wall.
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post #107 of 191 Old 04-09-2012, 02:22 PM
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Quote:
Originally Posted by kgveteran View Post

Just more rantings..... I bought War Horse on BR. I thought the movie was great. I decided that i wouldnt be building anything soon, so i would back off the AUX subs so i dont damage them. So, I back off the input gain on the plate amps, and lo and behold..... The movie sounded awesome. The 12's were happy with the new level setting.... So, like a good tweaker i began to raise it to see where they would begin to show signs of stress. I then backed the gain a little and continued with the movie.

Later that night i ran some sweeps to see where i was in my graph world. Seems the hole i filled in all but about -5db. I will now begin a slow build and enjoy the subs as they are. They filled in quite nice.....

The experment was still a success as multiples is the way to go.

It's been an interesting read. I've never understood the logic in having less capable drivers as fillers, because as soon as you use the main subs to full capacity, then the fillers will start to audibly complain.
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post #108 of 191 Old 04-09-2012, 03:22 PM
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***I've never understood the logic in having less capable drivers as fillers, because as soon as you use the main subs to full capacity, then the fillers will start to audibly complain.

If the system is properly set up, the fillers play much quieter than the mains. Typically, sub 2 seems to end up at 3-6dB or more down, and sub 3 often even lower than that.

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post #109 of 191 Old 04-09-2012, 03:28 PM
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Originally Posted by A9X-308 View Post

It's been an interesting read. I've never understood the logic in having less capable drivers as fillers, because as soon as you use the main subs to full capacity, then the fillers will start to audibly complain.

The fillers would only need to match the main subs capacity if they were reproducing the same spectrum and amplitude as the main subwoofers. Since multiple sub locations are only beneficial above the room's fundamental resonance (with kgveteran's big offender at 52Hz) that needn't be the case and each octave removed from their drivers via a high pass (electrical or mechanical resulting from the driver + box mass/spring system) reduces the excursion limited headroom requirements by 75%. There's also the reduced amplitude requirement.

Obviously there's still a limit - one 12" driver per location with 3-6 dB of attenuation only skipping the main subs' last octave isn't going to keep up with four 15" units.
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post #110 of 191 Old 04-09-2012, 03:51 PM
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Originally Posted by A9X-308 View Post

It's been an interesting read. I've never understood the logic in having less capable drivers as fillers, because as soon as you use the main subs to full capacity, then the fillers will start to audibly complain.

Good point, if done full stop, all subs would really need to be of equal capability. But then, by definition, they'd not be balancing subs.

In my experience, most modal issues that need addressing don't exist down low in the subwoofer range. That said, if one had ample performance in the frequency range of interest, high passing below the modal range, it would seem you could get away with the somewhat lesser sub in this limited bandwidth role. I've not done this, with limited bandwidth, limited capability (relative to the main sub system)...so I can't speak first hand.

Procella's selling purpose built balancing subs, as I inquired about them and checked them out while at their Cedia dedicated sound room. Their mains are killer, I'm not so hot on their subs.


Continued good luck KG,...thanks for sharing....


edit,..didn't see the above posts with the same points...

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post #111 of 191 Old 04-09-2012, 04:07 PM
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Originally Posted by Drew Eckhardt View Post

Obviously there's still a limit - one 12" driver per location with 3-6 dB of attenuation only skipping the main subs' last octave isn't going to keep up with four 15" units.

Precisely. A quad of Tumults has nearly 14x the Vd of a single Dayton, so even high passed at 40Hz or so, a signal in-band could potentially overload the fillers, which definitely seems to be the case here. At say 50hz the Tumults could be loafing along even at relatively high level sounding clean where the 12" is working hard and making itself audibly apparent.

I've seen lots of FR curves for these set ups at low level, but yet to see one near reference.

Geddes is a tight arse looking for a solution that will get acceptable results (to his standard) at a price that he sees he can convince his customers to pay (whether they buy his subs or someone else's), ie suits his agenda, and I'm sure I recall him saying that he doesn't listen at/near reference and doesn't believe most people do, so tailors his solutions to that. However, some people do like to have full SPL capability, and high output very low, so I'm seeing there is potential for his methodology not to work in the more extreme set ups. Most HT users with the exception of those who frequent forums like this particular one, will likely not have subs as capable as KGVs.
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post #112 of 191 Old 04-09-2012, 06:36 PM
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Originally Posted by A9X-308 View Post

Precisely. A quad of Tumults has nearly 14x the Vd of a single Dayton, so even high passed at 40Hz or so, a signal in-band could potentially overload the fillers, which definitely seems to be the case here.

I agree with you that his ratio is a bit skewed. If I were him I'd put two of the Tumults in a front corner, two of them far away from that corner and from each other, and mount the new Dayton subs up high. Now, I'm not him, obviously...

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I've seen lots of FR curves for these set ups at low level, but yet to see one near reference.

Like any bass system, they track the volume displacement and available power. Though they will probably do a little better than systems with the same Vd but fewer motors, because there will be less thermal compression.

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I'm seeing there is potential for his methodology not to work in the more extreme set ups.

Why? One just needs to scale up the individual subs to meet one's SPL demands.

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post #113 of 191 Old 04-09-2012, 06:37 PM - Thread Starter
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He there KG,
I've enjoyed your thread so far...it's been fun to watch you experiment. From what I've read from the multisub approach (at least Geddes's version), the sub nearest to you should be barely audible. It's only there to fill out the frequency response. Not sure exactly how your room is set up, maybe you could combine your 2 Dayton's into one larger sub, and pick up one (or 2)more to be the "3rd" sub in the Geddes arrangement.
It sure doesn't sound like you are very far off. Have fun!

At this point i have to say it is more like a Geddes approach due to the number of subs (3) , Quads counting as one.
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post #114 of 191 Old 04-09-2012, 06:44 PM - Thread Starter
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Originally Posted by robseyes View Post

He there KG,
I've enjoyed your thread so far...it's been fun to watch you experiment. From what I've read from the multisub approach (at least Geddes's version), the sub nearest to you should be barely audible. It's only there to fill out the frequency response. Not sure exactly how your room is set up, maybe you could combine your 2 Dayton's into one larger sub, and pick up one (or 2)more to be the "3rd" sub in the Geddes arrangement.
It sure doesn't sound like you are very far off. Have fun!

It does resemble the Geddes setup with the quads acting as one sub....

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KG-

I haven't been following your thread, but I think you are finally doing it right and that is why you are getting good results. Those Dayton's definitely can't keep up with your mains if you try to play them at full tilt. I would have suggested something completely different if that was the intended use.

I would suggest re-working your eq now that you have it setup as a more inline with Geddes methods. You might also try moving the LP XO point up a bit. Basically make it as high as you can go without having localization issues. Modal smoothing from 80-120hz is very beneficial. It is vital that the smoothing/aux sub is only playing at a fraction of the level of your primary subs.

Did you ever separate your 4 15's into two separate boxes? That would yield even further improvements as you could place one box in a corner and another mid-wall.

I need to read up on the Geddes method, and at this point i might as well keep my eyes open and my brain open to new idea's. So are you saying there could be more to gain by raising the sub XO, modaly ( if thats a word ). I will add that to my clip board. I really like the fit and finish of the new subs, it would be nice to keep them if another method works with kinda highish SPL's.
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post #115 of 191 Old 04-09-2012, 06:47 PM - Thread Starter
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Originally Posted by DS-21 View Post

If the system is properly set up, the fillers play much quieter than the mains. Typically, sub 2 seems to end up at 3-6dB or more down, and sub 3 often even lower than that.

That was what i was trying for, hoping the Daytons had enough omph to handle the narrow bandwidth, but as it was setup they were not.....
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post #116 of 191 Old 04-09-2012, 06:53 PM - Thread Starter
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Originally Posted by Drew Eckhardt View Post

The fillers would only need to match the main subs capacity if they were reproducing the same spectrum and amplitude as the main subwoofers. Since multiple sub locations are only beneficial above the room's fundamental resonance (with kgveteran's big offender at 52Hz) that needn't be the case and each octave removed from their drivers via a high pass (electrical or mechanical resulting from the driver + box mass/spring system) reduces the excursion limited headroom requirements by 75%. There's also the reduced amplitude requirement.

Obviously there's still a limit - one 12" driver per location with 3-6 dB of attenuation only skipping the main subs' last octave isn't going to keep up with four 15" units.

That was my thought after the initial listen, they measure fine, at about 85db sweep track #2 on the OM. Program material is a whole different story, and when you throw in DEQ, well thats another variable. i have to say I really enjoy watching a movie at -15db and still be blown away with the DEQ engaged !!!

My clipboard if filling up with some new idea's...time and money will tell...
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post #117 of 191 Old 04-10-2012, 02:47 AM - Thread Starter
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Originally Posted by A9X-308 View Post

It's been an interesting read. I've never understood the logic in having less capable drivers as fillers, because as soon as you use the main subs to full capacity, then the fillers will start to audibly complain.

The Welti Devantier method would require equal output capability from all four, or at least in my case, they need to keep up with the quad main system.....thats a tall order for a 12" driver of any make...

I'm gonna do some futz'n around with the Geddes method, kinda wrap my head around it alittle and see if there is merit to it, which i dont doubt, but time will tell.

I threw in Song Remains The Same last nite on BR to see how the AUX's do with a music sound track. Once i raised the subs a bit and faded the sound to the rears more to get a little more envelope, it just came to life, Bonhams drums were centered and as musical as i would ever expect out of a soundtrack that is close to 40 years old. Pages guitar work was so flippin solid it was silly. I had no idea how much John Paul Jones added to the music with keyboards. and of course Robert Plants voice was un strained.... This is a must for any Zepp fan.

Sad to say John Bonham passed away as i held tickets to see them in buffalo September 1980.....sad damn day, just plain sad....
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post #118 of 191 Old 04-10-2012, 03:37 AM - Thread Starter
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Precisely. A quad of Tumults has nearly 14x the Vd of a single Dayton, so even high passed at 40Hz or so, a signal in-band could potentially overload the fillers, which definitely seems to be the case here. At say 50hz the Tumults could be loafing along even at relatively high level sounding clean where the 12" is working hard and making itself audibly apparent.

I've seen lots of FR curves for these set ups at low level, but yet to see one near reference.

Geddes is a tight arse looking for a solution that will get acceptable results (to his standard) at a price that he sees he can convince his customers to pay (whether they buy his subs or someone else's), ie suits his agenda, and I'm sure I recall him saying that he doesn't listen at/near reference and doesn't believe most people do, so tailors his solutions to that. However, some people do like to have full SPL capability, and high output very low, so I'm seeing there is potential for his methodology not to work in the more extreme set ups. Most HT users with the exception of those who frequent forums like this particular one, will likely not have subs as capable as KGVs.

Yes, i listen it higher SPL's than i though, it doesnt sound like it, but there were times in War Horse that i was doing about an inch and a half peak to peak on the main subs, with not even the hint of strain.......maybe even 2" P to P.

Which leads me to believe, there are a pair if 15's or even 18's in my future with a nice pro amp to boot ! Sundown has a reasonable priced 15 and a dealer lives close by......

I have to keep saying, the MiniDP and OmniMic are a real treat to use. What an investment the OM has been....
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post #119 of 191 Old 04-10-2012, 05:43 AM
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The key to using a Geddes style "filler" sub of less capacity is that it is set to a level that is a fraction of the 1st two sub locations. Of course these will not keep up with Tumults if they are asked to do the same duty.

The reason for using this smaller, lower output sub are twofold. First, most people are limited in space towards the back of the room and can't afford to have mammoth subs back there. Second, you can have imaging issues if you run the rear filler sub at a level equal to the front subs.

The reality is that with a highpass around 30hz and running at least 8-12db lower than your Tumults, these subs should be fine unless you are running maybe 10-20db over ref.

Your setup is less than ideal IMO. I would prefer that you separate your Tumults into two separate locations and colocate the Daytons and find a single location in the back of the room. I'm sure you can make it work well as it is though.

Frankly, IMO, the Geddes approach is practically superior to Welti/Devantier. I'd guess that Geddes utilized Welti's research and the approaches certainly work on similar principles, but the Geddes approach is more flexible and reasonably executed. For the Welti approach you basically need the same capacity in each sub location and some symmetry. You built more towards the Geddes approach, but implemented the Welti approach.
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post #120 of 191 Old 04-10-2012, 05:53 AM
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Originally Posted by kgveteran View Post

That was what i was trying for, hoping the Daytons had enough omph to handle the narrow bandwidth, but as it was setup they were not.....

Well, for one thing your main sub and your "broadband" subs have a much bigger disparity than ~6dB output potential.

Second, you're using the Dayton SA240 plate amp on the Dayton Ref subs, right? That amp works pretty well for efficient vented subs, but clips clips clips when asked to drive closed boxes. So perhaps using more power will help.

Even on a Peerless XLS12 Application Note sub, which is a lot more efficient down low than any small closed box, I was surprised how much swapping out the SA240 for an Oaudio 500W plate amp increased the system's headroom. I don't think the SA240 puts out the claimed output. I'm glad I just have one and not the 4 I had planned to buy at one point (Genelec HTS6 clone) because I am not at all impressed with that amp...

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