New GRS driver suitable for an ultra cheap THT?

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JensToft91
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New GRS driver suitable for an ultra cheap THT?

#1 Post by JensToft91 »

Hi all

Seen the new GRS 12SW-4HE driver? It looks very similar to the recommended Dayton driver. But it only costs 60 euro.

Any reason it shouldn't work in a THT?

Grs 12 inch
22 hz
Qts 0.43
Vas 2.84 ft3, 80.4 L
12 mm

Dayton RSS
24.2 Hz
QTS 0.39
84.1 L
14.3 mm

howiez
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Re: New GRS driver suitable for an ultra cheap THT?

#2 Post by howiez »

The specs all look good except the Vas, I would defer to Bill on that. My guess it'll probably be fine. Be interesting if it works well, for that price. I'm planning to use a GRS 8" in my DR200 build, price being the reason as well, so I look forward to your results as well!

I might add, in my THT build, I started with an 'unsanctioned' driver, and it worked, and sounded great. But when I replaced it with the Dayton RSS390HF, it really woke up. I never would have believed it if I didn't hear it myself. Anyway, that was an apples to oranges comparison, your case is only off by a few points in the Vas, so I'd say try it!

JensToft91
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Re: New GRS driver suitable for an ultra cheap THT?

#3 Post by JensToft91 »

I found someone who made a hornresp file (using pictures, so not an accurate one), but I modelled the differences, at they are tiny.
I'm planning on making the smallest possible THTLP - not knowing exactly what a few L of Vas does, but maybe it helps in the smaller cabinet.
I think I'll wait for Bill - he's probably interested in a cheap 12" option as well.
Right now, I Can't decide whether to use my SVS PC12 for the low end, or my slim TT for the punch. Right now I'm using the TT, simply because it sounds better.
I think the THT will be right on the money for me - I just like "dirt cheap and awesome". The GRS will put the 12" THT right in that alley.

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Bill Fitzmaurice
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Re: New GRS driver suitable for an ultra cheap THT?

#4 Post by Bill Fitzmaurice »

I'd use it.

JensToft91
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Re: New GRS driver suitable for an ultra cheap THT?

#5 Post by JensToft91 »

Bill Fitzmaurice wrote: Mon Dec 20, 2021 5:49 pm I'd use it.
Great! Thank you.
The expensive drivers for the THT was what held me back the most. Now I don't really have an excuse anymore.
I only have one question about the THT, I've been thinking about.
I've read a post from you, Bill, on techtalk Express, where you state "I designed the THT specifically for those who don't understand horns and insist that they have to use a fifteen."
What does that mean? My first thought was "Is there a design for people who don't insist on using 15's, but want 20hz extension?"

I would love a smaller version, with 20 hz extension - as I think the TT drops off a bit too quickly.

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Bill Fitzmaurice
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Re: New GRS driver suitable for an ultra cheap THT?

#6 Post by Bill Fitzmaurice »

It means that I didn't design the THT based on the need for a fifteen loaded sub in the home, as there is none. A twelve is sufficient.

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Re: New GRS driver suitable for an ultra cheap THT?

#7 Post by JensToft91 »

Right! Makes sense. Cheap 12", Slim THTLS it is.

Would it be a sin to build it in MDF? I don't think I'll ever feed it more than 50w.

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Re: New GRS driver suitable for an ultra cheap THT?

#8 Post by JensToft91 »

Uh, sorry - The super cheap MDF I have available is not big enough to build it anyway - so i won't be using it anyway :-)

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Re: New GRS driver suitable for an ultra cheap THT?

#9 Post by ACUA »

I built many car subwoofer boxes out of MDF in my days. I will never use it again. I’m glad to see affordable drivers that are viable options.
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Seth
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Re: New GRS driver suitable for an ultra cheap THT?

#10 Post by Seth »

I would use (and have used) inexpensive 5 ply 15/32" CDX sheathing plywood way before I'd consider MDF. Between the two, my opinion is that the only benefit of MDF is that it takes no extra work to get a nice smooth outer surface. The main downsides are weight and lack of strength. But, there's also a noticeable difference in how it cuts and the mess it makes. Let alone MDF's lack of moisture resistance that shows little cancers in the finish if it happens to get wet or stored in a less than dry environment. Last I checked (pre COVID) the ply was less expensive too. And really, the cost to go with Baltic Birch Plywood isn't all too much more and is even easier to work with and has the benefit of a fairly smooth outer finish too. The CDX is inexpensive and weighs less than Baltic Birch, but can warp much more than BB (which most times doesn't warp at all) and the CDX also takes more work filling voids and sanding to get a nice finish. So, as usual, there's plusses and minuses to each option. But, there's almost no reason I'd ever build with MDF again. The only thing I can think to use it for is shelving.

Of coarse, there's grades between CDX construction/sheathing ply and Baltic Birch to choose from. Baltic Birch is the preferred material unless slight cost or weight concerns make other options more applicable to your project. Just the way I see it.
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JensToft91
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Re: New GRS driver suitable for an ultra cheap THT?

#11 Post by JensToft91 »

Thank you for the answers. I'll find the cheapest ply available.
Now I just need to decide, if I really need the upgrade from the TT. It's a damn good sub - but coming from a quite cabable 18 Hz ported, I know what's missing - and that's probably the only reason I even consider upgrading.

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Bill Fitzmaurice
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Re: New GRS driver suitable for an ultra cheap THT?

#12 Post by Bill Fitzmaurice »

I'd have to see the measured results to believe that a ported cab beats a wide TT, other than having much higher THD. :?

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Re: New GRS driver suitable for an ultra cheap THT?

#13 Post by JensToft91 »

I have the narrowest TT - and I'm only taking about ~18-25 Hz range.

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Re: New GRS driver suitable for an ultra cheap THT?

#14 Post by JensToft91 »

Edit. 18-30 hz range. The TT comes alive at 30hz- but quickly drops below.

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Re: New GRS driver suitable for an ultra cheap THT?

#15 Post by JensToft91 »

Soo. I got an idea.
Until I decide to build the THT. I will hook up my ported sub, highpass my TT at 28 Hz (because of driver distortion at 25 Hz) and then lowpass my ported sub at 28hz, matching the phase of the two.
The distortion you are talking about, Bill, really became evident. Level matching the 2 subs at 30 Hz - not anywhere near the limits of the TT, the ported sub is already putting out audible port-noise at 25 hz.
Guess the THT is the only way to go 😁

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