MTH30 Questions : Complete Noob!

[turbodawg]

Originally Posted by weltersys

Turbodawg,

You are using the Dayton Reference 15 four ohm driver in a very small low tuned ported box.

It is only 87 dB one watt one meter at 100 Hz, and drops considerably in sensitivity from there, probably in the 80 dB one watt one meter range at Fb.

Have you any measurements?

Art

Hornresp sim's to a 40-50hz peak over 95 db/m/2pi at 2.0V input, aka nominally 1w, and -3 db around 34 hz. It has a mildly peaking response with lots of gain from the port, like a house curve, and I'm using a bit of overlap at the crossover to fill in the midbass. Dayton's spec sheet calls their shown response below 200hz as "not actual". These simmed higher sensitivity than other smaller drivers, the only thing comparable was some of the eminence LF models.

I could use my analog rat shack SPL meter with correction data to pull some numbers, if I get around to it.

Running full range music, bass heavy, I've hit over ~115db peaks in the middle of the room, the RS meter is accurate "enough" for that, without the system breaking a sweat or the subs near xmax.

[weltersys]

Originally Posted by turbodawg

Hornresp sim's to a 40-50hz peak over 95 db/m/2pi at 2.0V input, aka nominally 1w, and -3 db around 34 hz.

I guess I could use my analog rat shack SPL meter with a correction file to pull some numbers, if I get around to it. Trust me, it's loud.

I'll trust it's loud to you .
You claim a response 8 dB above a manufacturer's specification, and have not bothered to put a dB meter in front of the cabinet?

Please show us the Hornresp input screen and FR that result in an 8 dB sensitivity increase over the manufacturer's specifications and a measured response at a few frequencies.

[turbodawg]

Originally Posted by weltersys

I'll trust it's loud to you .
You claim a response 8 dB above a manufacturer's specification, and have not bothered to put a dB meter in front of the cabinet?

Please show us the Hornresp input screen and FR that result in an 8 dB sensitivity increase over the manufacturer's specifications and a measured response at a few frequencies.

I'll see what I can do, but I've got many projects in process right now. Taking an inaccurate measurement of these is not a high priority. I'm confident of my ablity to use simulation software and casual observation seems to indicate they are performing as expected.

[PASC]

[QUOTE=ghettosynth;3338791]Thanks, to be clear, did you mean 6 of the MTH30? I read in another thread that the 12ps100 didn't simulate well in that cabinet so I want to make sure that you aren't talking about the THAM12?

Hi!

Yes, 6 MTHs.

12PS100 has a strong cone, good xmax 8mm, 700W Pe, goes low, and plays nice innit from 40 till past 100Hz, with good and defined notes reproducing the bass guitar. To me is more than enough.
Make one and hear it with your ears, measure it, ...
Compare it with what you have and make your decisions.

Isn't it this driver in the Danley miniTH? Why? How much is the sensivity claimed?
Think that the SPL/response should be measured within the band it will be used, as a subwoofer, and not when the thin cone or drivers dome plays full range as could be observed at the drivers PDFs.

Due to the cost of it at my country decided on the 12CL76, which costs half compared to the 12PS100. Is a bit more sensitive so final SPL within limits are near same, also sound is near like it, but the cone is not so strong.

No, not the THam 12.

Regards,

[weltersys]

Originally Posted by PASC

Yes, 6 MTHs.

12PS100 has a strong cone, good xmax 8mm, 700W Pe, goes low, and plays nice innit from 40 till past 100Hz, with good and defined notes reproducing the bass guitar.
Isn't it this driver in the Danley miniTH? Why? How much is the sensivity claimed?
Think that the SPL/response should be measured within the band it will be used, as a subwoofer, and not when the thin cone or drivers dome plays full range as could be observed at the drivers PDFs.

Hi Pasc,

As far as I can tell, the DSL TH Mini uses the B&C12TBX100, which on paper is a tiny bit more sensitive than the BC 12PS100, 2 Hz lower Fs and has 9mm Xmax and 11mm Xvar, and 300 watts more power handling.
In my testing of the BC18SW115 I found the Xvar excursion and rated power handling completely usable, so if one can afford the 12TBX100, it is worth the extra output potential in whatever box it is in.

Still using the Keystone?

Art

[weltersys]

Originally Posted by turbodawg

I'll see what I can do, but I've got many projects in process right now. Taking an inaccurate measurement of these is not a high priority. I'm confident of my ablity to use simulation software and casual observation seems to indicate they are performing as expected.

Even a quick measurement would probably be more telling than the simulation.
Using the Dayton Reference 15 in a simulation of about 90L net (20x22x16 using 3/4") 2 volt with a 35 Hz Fb does show 95 dB at 60Hz, 91.96 at 40Hz, but only 89.34 at 35 Hz. At 30 Hz it shows 85 dB.
Hornresp is very useful, but it often shows peaks larger than reality, and drooping upper response (or more LF response) than real measurements.

Comparing the real measurement of my Lab 2x12" to the sim, the sim shows the response at 40 Hz to be some 10 dB higher than 500 Hz, while it is actually 2 dB less.
I built the Lab 2x12" before using Hornresp, that peaky port "boom" Hornresp predicts would have scared me off.

If the same holds true for your Dayton Reference 15 in a 20x22x16 35Fb box, it may be closer to 87 dB than 95 dB sensitivity.

Art

[PASC]

Originally Posted by weltersys

Hi Pasc,

As far as I can tell, the DSL TH Mini uses the B&C12TBX100, which on paper is a tiny bit more sensitive than the BC 12PS100, 2 Hz lower Fs and has 9mm Xmax and 11mm Xvar, and 300 watts more power handling.
In my testing of the BC18SW115 I found the Xvar excursion and rated power handling completely usable, so if one can afford the 12TBX100, it is worth the extra output potential in whatever box it is in.

Still using the Keystone?

Art

Hi!

12PS100 Item Price: $205.95
12TBX100 Item Price: $294.95
Difference............+ $ 89.00 43%more per driver.

If you have the money for the difference of cost and and so for bigger amp to earn some 1.5dBs ok.

Not have chance to test the 12TBX100 yet.

When tested in the TH18, the 18TBX100 beside 18LW2400, it didn't impress me so much. 2000W to do the same as the 18 Sound one with 1300W, and travelling a lot despite carefull low-cut set.

Keystone: Despite good results, after tests, shame it is parked at my garage as is the TH18. Driver costs to much here due taxes. But was a good study to me.

Regards,

[Brian Steele]

Originally Posted by weltersys

Comparing the real measurement of my Lab 2x12" to the sim, the sim shows the response at 40 Hz to be some 10 dB higher than 500 Hz, while it is actually 2 dB less.

HornResp doesn't take losses into effect, if I remember correctly. Gotta be a bit careful when using it to sim vented boxes.

[Brian Steele]

Originally Posted by weltersys

My statement that the MTH30 does not look like a particularly good TH design is based on comparing it to others that appear better in terms of output vs. size and frequency response.

Do you have access to HornResp predictions or actual measured FR or PR response curves for the MTH30?

[weltersys]

Originally Posted by Brian Steele

Do you have access to HornResp predictions or actual measured FR or PR response curves for the MTH30?

No, just my meat computer generated response curves .

I'd like to see sims, actual measurements, or direct comparisons if anyone has made them, but found none in my quick review of the MTH30 threads I came across.

Maybe Pasc could compare the MTH30 to the XOC1 TH18 or my Keystone and give us an idea of FR, sensitivity and output potential.