Sorry this took so long folks. I had to upgrade mongodb driver from v2 to v6. And nodejs needed to be bumped too.

I think I'll move the code to github and make it opensource so more than 1 person can make pull requests

Note: There are still some broken elements but thats all on the admin side.

anyone been in contact with josh recently? I have not been able to get a hold of him.

On 8/4/2023 at 12:21 PM, popalock said:

I took data-bass for granted and now it's gone...😩

Didn't even have a chance to offer Josh to take my money to keep it going...😫

We coulda did some targeted troll marketing to brand this website as, "The Site All Speaker Companies HATE,"...😭

Trump could have sold his NFT's on the site and we could have just been perpetually self-funded by idiots...😣

Why do all my good ideas come so late in the game.  Makes me...🤢🤮

LOL, ya, it takes work to maintain or make money. nothing is easy, but I do want to try and limp this project along if I can. 

Its not (which is good news), mongodb did an upgrade from 5 to 6 and the driver I'm using in nodejs is not working with the changes. I need to make several code changes to hook that up. 

the second issue is a refactor I did a while back but didnt correctly update the react UI to work with the new API so we can't create or edit any systems or drivers. Its a bit more work for figure that out, but my guess is about 3-4 days tops. I might be able to do it in this quarter.

@Ricci send me a message!

eh...
 

need to update the mongodb driver, which is a PITA bc I really need to upgrade nodejs and react too. If you dont constantly update software, eventually it deprecates.

I'll get on this

nt = notext

Hey folks, I think everything runs its course and since I have not been updating db.com, I have not giving much attention to the forums either.  At this point, there is a ton of great discussion here. I think invision has a self hosted option, but I don't see a price for it. It might be expensive too.

In any case, these forums are $30 a month and lately I don't see the value in keeping em going because we don't have a lot of activity. I don't want all the content deleted, but I'm at a point where $30 every month is getting old for me. Any thoughts? I'm also willing to transfer ownership if anyone wants to take these over.

On 5/29/2021 at 12:31 PM, kipman725 said:

I think from the datasheet the 18mm is when BL=0.7*MAX(BL).  Looks like a great deal for the price, shame that price will not be anything like that in the UK.  I wonder how it would do in a FLH like the lab horn?

Probably decent, the Lab 12 has great mms and BL for its size giving it a low Q so it would work well in a horn. I don't see any reason this couldn't.

Looks like a new driver, not half bad on paper. Reasonable BL, not too too high mms. Price is solid too.

https://www.parts-express.com/Dayton-Audio-MX12-22-12-Max-X-High-Excursion-DVC-Subwoofer-2-Ohms-Per-Coil-295-166

https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-parallel-and-series-resistor

The speakerpower can do 2+2 so you'll want to try and land a 2ohm load per channel. Look for a driver with a ~5 to ~6 ohm DCR and if you take 3 of them in parallel you're gonna a be right at a 2 ohm nominal load. Perfect for each side of your amp. Are you set on have 6? 4 21's is still a lot and may be easier to deal with.

The size of the driver does not make it fast or slow. In this case, you have low delay because its a sealed box. The HS-24 would perfectly fine for music, but you do need to couple it with a large box because of its higher Q of about 0.5. A big sealed box would be perfect for this driver.

Also, to understand why group delay is a much more apparent with a port / horn (compared to just a driver in a sealed box) because the port, unlike the driver acts like a spring mass system. When you apply a voltage to the driver, its ridge and starts to accelerate more or less as a rigid body. But when you apply a force to a spring-mass, then it acts differently compared to the input signal. I'm honestly not sure how group delay is perceived in terms of subjective sound quality -- I hope some others chime in.

Welcome to the forum.

I have not looked at these designs in detail, but my 2cents. If you're using a high sens. pro style driver, I don't really see how the system benefits from putting that kind of driver into a 6th order bandpass because the bottle neck is still the low end and its not lacking in mid-bass punch. Using the same size box, you can make the simple 4th order with a larger port with more headroom. I would be interested to see if anyone has experimented with 6th order and compared it to standard ported boxes (same size) with these type of drivers.

20 hours ago, SME said:

I've always regarded MDF to be heavier than BB plywood, so I decided to try looking it up:

https://www.inchcalculator com/how-much-does-plywood-weigh/

Different products will vary a bit, but the chart there suggests BB is only about 70% as heavy as MDF.  I do agree that BB plywood is stronger and more durable than MDF.  There are other pros and cons.  MDF is more messy and toxic to work with (dust) but also a but more forgiving.  MDF has more adhesives which may improve its damping properties.  Many speaker makers argue that the damping properties of MDF make it superior to BB despite the lower stiffness-to-mass ratio.

My thought is that MDF is OK for things that don't get moved/transported a lot and where weight is not important.  For big subs that get moved around a lot, MDF is not a good idea.

If BB plywood is exceedingly expensive in AU/NZ perhaps look for another high quality hardwood plywood product.  As I noted above, BB tends to have thinner plies than other types.  Another benefit of BB plywood over other stuff is that it tends to be void free.  (Tends to---alas the last stock I bought still has a few small gaps )

I will agree to pretty much everywhere here.

BB is nice for things that get big, even if you don't move it much. When you do need to move it (and you will) you won't regret the BB. 

On 9/22/2020 at 5:09 AM, peniku8 said:

That's what I tell people as well. Make the sealed sub as big as you can, until you can reach Xmax at Pmax. Usually the cab will be smaller than what it takes to do so, so it doesn't make sense bothering with a HPF, unless you wanna reduce the load on the sub, like when you HPF it at 15Hz because your sealed 12" sub won't have meaningful output below that anyways.

 

Was it a 5400?

no, thank god! it was just a 12" TC-1000 / Epic. Good little driver, plenty loud for my small loft.

I don't add one on my sealed HT sub, then again, I made a mistake once with the amp maxed out and now I have a voice coil ring dent on my metal dish cone

Still works fine tho!

7 hours ago, jay michael said:

Thought I should update this thread as I went ahead and built a pair of VBSS subs to live with my Danleys.  The hype is real, these are fantastic sounding subs considering their inexpensive cost to build. They wont crack the stucco on my ceiling like the Skrams did, but for listening to music at moderately loud listening levels I couldn't have wished for a better outcome. Thanks for the help everyone, the project was a success! And I didn't blow a bunch of money I didn't need to spend in these strange times.

Aesthetically I think they make for a great match with the Danley's as well.

https://imgur.com/gallery/R1JSs05

 

Looks nice! I bet they sound fantastic!

10 hours ago, ErnieM said:

Yes, that was the one. We'll see how the fixed drivers compare with the two good ones I have.

I wonder if it's more common on these high xmax accordion surround drivers.

I tend to think its a glue problem, or primer problem. 

On 6/29/2020 at 5:59 PM, peniku8 said:

Interesting, I also had a problem with one of the 14 Dayton woofers I recently got. Very similar noise, just that I was testing at 20Hz so the "clicking" was slower. The issue doesn't seem to come from the surround on the Daytons, more like the noise comes from the phase plug (those woofers have a solid phase plug in the center instead of a dust cap).

Hard to tell what that might be, best to return it if you can? The noise may be coming from the motor or voice coil. The phase plug won't likely be making any actual noise itself, but any number of things could be wrong with that driver, its very hard to tell sometimes what exactly it is.

Any small issue with glue or primor can lead to failure. Its a bit tricky and takes precision. Hopefully Eminence can get those fixed for you

Welcome!

Are these new drivers or did they fail after some time?

Could be room issues. Its pretty easy to stuff your ports and get a sense of what a sealed box sounds like. The larger box volume won't negatively affect the midbass at all. Only really increases efficiency down low. Just make sure to turn off your high pass filter once you seal it... and go easy at first!

But what you really might just need it to figure out if you have some standing waves in that room that negatively affect the bass. Just move the subs and see what happens. I would also consider getting a higher efficiency 18" driver and just switching that. But before doing anything costly, what sort of power are you running to your subwoofers?

Gotcha Charles. Glad you like em! lets see some pictures

Old thread!

Yes @Charles the dual 4" ports will have a measurable advantage over the single, even with flaring. PSA subwoofers are interesting to me, it feels like they lean heavy on the driver and its motor and squeeze it in a smallish box (not every sub they sell is small) but many of the B&C drivers they use could gain more from a larger, box, however there is something to be said about how capable they can still be in a reasonably size boxed for home applications. Its kinda cool actually. What is the TV1812? I see V1812 with a slot port? that is ~6.1 cubic feet or so while the Rhythmik is closer to 8.8. If that's is accurate, then there is doubt the larger box and port will have a big advantage down low. But I could be wrong about my numbers ... someone should double check.