jm,
I have a Thruster myself so tried a M3 (0.5 pitch) screw and it fits, so that's it.
Now I understand your four screw solution, thanks for the picture. Nothing wrong with that, it sure looks secure to me. I think the single M3 screw would be fine too, or some foam and double sided tape too, as I've shared before.
Eric
I do not normally show plots with 10db spacing ( dotted lines )as it looks over beautified .
But I thought it might give a better overall picture.
There was a lot of traffic noise below 100hz, especially on the side plot.
The first picture is at 12inches in front of the low grade EPS panel.
The second is the same panel but from 12inches to the side of the panel.
I am now going to see how the small exciter performs on another type of panel.
How will it handle a lower efficiency panel, and how will the hf improve?
Steve.
But I thought it might give a better overall picture.
There was a lot of traffic noise below 100hz, especially on the side plot.
The first picture is at 12inches in front of the low grade EPS panel.
The second is the same panel but from 12inches to the side of the panel.
I am now going to see how the small exciter performs on another type of panel.
How will it handle a lower efficiency panel, and how will the hf improve?
Steve.
Attachments
Hi people
I would like your opinions on using a Dayton BASS DAEX32QMB-4 to create an exciter DML sub woofer.
My main panels will be 970 x 600 mm XPS with 40 watt Dayton Bullfrog Quad DAEX25X4-4 .
What size panels have proven successful with the BASS exciter compared to the main DML's ?
For example do smaller or larger panels work best with DML subs ?
Has anyone found a size ratio that works ?
I spent around 2 hours reading this thread so i did not read all 9400 posts , I also watched around 9 Youtube videos and did 10 hours research to arrive at the point where i think i have my mains sorted , just not sure on the Sub.
My Amp will be a TPA3251D
Any suggestions ?
I would like your opinions on using a Dayton BASS DAEX32QMB-4 to create an exciter DML sub woofer.
My main panels will be 970 x 600 mm XPS with 40 watt Dayton Bullfrog Quad DAEX25X4-4 .
What size panels have proven successful with the BASS exciter compared to the main DML's ?
For example do smaller or larger panels work best with DML subs ?
Has anyone found a size ratio that works ?
I spent around 2 hours reading this thread so i did not read all 9400 posts , I also watched around 9 Youtube videos and did 10 hours research to arrive at the point where i think i have my mains sorted , just not sure on the Sub.
My Amp will be a TPA3251D
Any suggestions ?
If these are built the same as the DAEX32Q-8 that have the springs and rubber boot I would advise you to stay well clear of them for any project. For bass you're going to want an exciter with a long excursion, this exciter is not that, it's exactly the opposite. I have a few posts on this exciter. :
post # 7847 https://www.diyaudio.com/community/...ll-range-speaker.272576/page-393#post-7211836
Last edited:
My suggestion: Use a different exciter.
Here are my comparisons. Blue is the DAEX32QMB "Megabass"
40W exciter, the red curve is the DAEX25Q-4, which is only 20w, and sounds a helluva lot better. These measurements are done on 550 x 450mm Polycarb Twinwall, 70kg/m3 density, mounted with the whole of the top edge fastened to a support with 1.5mm double-sided foam.
I first tested the 32QMB, and I thought that the panel was too small to produce decent bass. Shrug. Carry on... Imagine my surprise when I used the little 25Q instead! And it produced that deep bass that I was missing. AND nice tops too.
So for live gigs I've been using 4 x DAEX25Q-4's per side on 1,400 x 450mm Twinwall panels. Sure that's only 80W per panel, and I'm driving them really hard, maxing out a 150W-per channel amplifier. But they've survived.
Are you thinking of using a really big panel (a projection screen with exciters on the back?) Or are you going to house them in a vented box of some kind?
After
I dont have a target frequency range , just looking for the best i can achieve , However i emailed a few Audio stores and the replies i have this morning state none of them believe that an exciter can replace a conventional subwoofer.
I am not discounting however that people on this forum could have proven otherwise.
Thanks Steve , this is home audio including outdoor parties on a large rural property.
I dont have a target frequency range , just looking for the best i can achieve , However i emailed a few Audio stores and the replies i have this morning state none of them believe that an exciter can replace a conventional subwoofer.
I am not discounting however that people on this forum could have proven otherwise.
These are the Quad and Bass exciters above and your DAEX32Q-8, I have seen a few posts where the feet of the Q8 were perceived to cause deterioration however the first two i posted have no boot and different springs.
I think my mains on 970 x 600 panels could still be either two units per panel of DAEX25X4-4 or the Bullfrog above if there are no contrarian opinions , I dont yet know if 25 mm exciters will carry sharper highs than 32 mm ones . . . .
Is it possible i will get cleaner notes from using ;
mid sized 300 x 485 thin panels with 25 mm units for highs
large sized 970 x 600 x 25 thick panels with 32 mm exciters for mids and highs
conventional subwoofer for lows.
I will do more reading and perhaps spend $ 40 - 50 to test the theories ?
Thats very interesting however we are missing a range of potential parameters that prevent me from dismissing the 32QMB Bass unit just yet.My suggestion: Use a different exciter.
Here are my comparisons. Blue is the DAEX32QMB "Megabass"
These measurements are done on 550 x 450mm Polycarb Twinwall, 70kg/m3 density, mounted with the whole of the top edge fastened to a support with 1.5mm double-sided foam.
I first tested the 32QMB, and I thought that the panel was too small to produce decent bass. Shrug. Carry on... Imagine my surprise when I used the little 25Q instead! And it produced that deep bass that I was missing. AND nice tops too.
View attachment 1145033
So for live gigs I've been using 4 x DAEX25Q-4's per side on 1,400 x 450mm Twinwall panels. Sure that's only 80W per panel, and I'm driving them really hard, maxing out a 150W-per channel amplifier. But they've survived.
If i test it on a larger thicker panel and it still cant provide the lows then i would have to go to a subwoofer.
Your Polycarb twinwall "looks" unlikely to carry lows but i didnt try any combinations yet so i am "philosophising" as Mel Brooks would say.
The guys at Parts Express and a local Audio dealer told me this morning that "No exciter exists that will replace a traditional cone subwoofer" but i might still try a theory or two.
PS. I dont think i will go as big as a projector screen as it would be a PITA to carry outside in the backyard and if i did take it outside a slight breeze could see it bouncing a few miles over the horizon , maybe could go up to 5 x 3 feet maximum but only if it produces a meaningful outcome.
Last edited:
My advice would be to just use a conventional cone powered subwoofer. It will save you a lot of time and money.
Just curious why you are set on a DML sub? By the time you get to that size panel it just seems more inconvenient and a hassle to deal with.
I am investigating if it can be done with different thinking but It might be a dead horse that needs to stay under that soil.
A DML would give cleaner architectural aesthetics inside the room , its that simple , If it costs $ 60 instead of $ 350 - 600 thats a also plus.
Why do Dayton market the QMB-4 as a Megabass or Bass product if it cant deliver when used correctly ?
If i was running their company i would publish a bit more information about the exciter applications , its a bit lacking IMO but they do want to sell other items in the product range that are higher value. ~
A DML would give cleaner architectural aesthetics inside the room , its that simple , If it costs $ 60 instead of $ 350 - 600 thats a also plus.
Why do Dayton market the QMB-4 as a Megabass or Bass product if it cant deliver when used correctly ?
If i was running their company i would publish a bit more information about the exciter applications , its a bit lacking IMO but they do want to sell other items in the product range that are higher value. ~
There are two problems building a DML-based sub. One is that you need substantial surface area since the whole thing works on quasi-open-baffle principles.
You will probably need at least the same surface area as 2 x 15" cone drivers to get decent bass. And if you use very a stiff panel, then the panel operates as a piston, and you will need large excursions on your exciter.
Secondly, to get around the excursion problem you might want to use a very floppy panel in order to produce bending waves at low frequencies. But then there's the problem of transient response. Yes, one can get very low frequency reproduction out of a reasonable-size DML panel, but no punch. It will sound 'floppy.'
Rather use a cone in a box and hide it in a corner behind a pot plant somewhere.
I suspect it's because one can crank up the bass EQ and drive large LF signals into this driver without it bottoming out. It has a very stiff suspension. Maybe it should only be used on high density, heavy panels?
But I can get the same, or better results with lighter panels and cheaper drivers and less drive voltage.
I'd love to hear the design philosophy behind this driver. (Keeping in mind it's not a Dayton design. I speak under correction, but think it was designed by the Chinese BillionSound factory. Good luck trying to get design info out of them... https://www.billionsound.com/product/226.html )
Last edited:
I suppose one could also put a very stiff panel, with an exciter on it, into a box... hmmm
The other alternative.
I was the one that suggested the bass shaker for the wall.
He also used an xo to prevent low frequencies from reaching the wall exciters.
Was the xo needed ?
Steve.
I went down that route it can be done as I can see the potential of a DML subwoofer but I dont have anymore funds to further my research and development of a DML sub. I have made 4 different prototypes of DML subs but have not fully achieved my goals due to lack of funds.
Its only cheaper if you have perfected a DML subwoofer design. R&D can cost way more then just buying a conventional cone powered subwoofer. You can also buy second hand subs on CL for a fraction of the cost.
Megabass is just a gimmick. There are other exciters better then the mega bass for low frequencies. Mostly all exciters frequency response starts dropping at 100hz as that is when the exciter starts to go into pistonic mode. The lower the frequency response goes the less the spl output. Decent spl output at 70hz but once it starts going lower output starts dropping like a rock.
I started recording at 2ft. away from the DML sub panel then moved about 2ft. more away. This is a small panel around 16inch width and 24inch height. using 2 tectonic 19mm exciters powered by a sub amp with low pass crossed over at around 120hz. I intially designed this DML sub panel to pair with some small DML satellite panels for "DESK TOP" duty that is the reason for the small exciters used in this sub panel design which makes spl output very limited up to 2-4ft. as they are suppose to be under ones desk fairly close.
Clever idea however the potentials were restricted by his set up.
He only had the exciters wedged under the strings so the strings would have carried sympathetic resonance , I would have removed the strings altogether.
What could they be with matched guitars and the necks and strings removed ?
And for that matter , what if you found an old cheap Cello or Bass to do it with to set up the lows ?
He only had the exciters wedged under the strings so the strings would have carried sympathetic resonance , I would have removed the strings altogether.
What could they be with matched guitars and the necks and strings removed ?
And for that matter , what if you found an old cheap Cello or Bass to do it with to set up the lows ?
Last edited:
No acoustic guitar or violin or piano or any other acoustic instrument is designed to have a flat response. The response of a specific instrument is tailored to emphasise and resonate at those frequencies that best bring out the characteristics of that specific instrument. So even if one DID do a perfect recording of, say, a Taylor Academy playing solo, and then played back that recording on another Taylor Academy with a driver on it, then those resonances that make it sound like a Taylor will be twice as loud, and the suck-outs will be twice as quiet, not forgetting the foibles of the driver itself.
Besides, the guy in the video should be placing the drivers at the bridge position of the guitar. That is where the strings couple to the instrument, and that is where the belly struts and braces are focussed. The position of the driver at the sound hole might give a big peak at around 200Hz.