Which 15 or 18 ınch woofer- best for open baffle

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#83
The Thornton 15" specs are a mess. 45 gram magnet? VAS of 25.9 Liters? 259L would be more likely. Until one could verify what the REAL specs are I would avoid this driver. It does have a passing visual resemblance to the Parts Express GRS-15.
 
#86
Low Price Woofer

Hi
it’s time for me to give some feedback 🙂
I went ahead and bought the Thornton T1501-45-8 15” woofer. At 259 dkr (35 EUR) each I thought that I would give them a try.
Before buying, I called the shop (Danguitar) and asked about the Thiele Small parameters, which looked a little suspicious (as John Busch pointed out). They could only agree and explained that they just printed the parameters as they received them from the manufacturer. But they promised me that if I did not like the drivers I could just return them. Great, I had nothing to lose then, and I decided to buy 10 woofers. 8 for open baffle config and 2 for a sealed box project I had going on.
And here I am. About 6 month later, and I am very very pleased with the sound I get. The speakers go deep. They start falling rapidly at about 28 Hz. So I guess the listed FS at 26 Hz is about right. I cross them over at 100 Hz 24dB-LR filter. I wouldn’t go much higher than about 110 Hz. The sound is deep, punchy and has good detail. 8 woofers move a lot of air and thus the distortion is low. But 4 woofers can also do, the job nicely.
There is however one thing I have to say about these low priced speakers. As Kjeldsen pointed out in an earlier post, the built quality is not great. I had to return 1 of the 10 woofers because it made a noise when pushed hard. But the return was easy. The shop just send me a new woofer. No questions asked!!! And now the only sound the woofers make is the one I want.😛
All in all I can only recommend these drivers. Are there better drivers out there? Yes most definitely, but NOT at this price tag. At least not in Denmark 🙄
 

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#87
I am considering upgrading my open baffle speakers with 15” woofers and I am looking for recommendations. Currently there are 2 x 15 in each channel actively crossed with DSP at around 250Hz. I use class D Hypex amp for the bass section.


Right now I have two options, either to go with Faital 15PR400 or PureAudioProject OB-A15SEN. Both lie in about the same price range (Faitals can be just a little cheaper). Both seem to have nice reviews for OB. From specs Faitals have quite low Xmax (stated 5.75mm, but if calculating with voice coil overhang it ends up just in 2.75mm) and low Qt = 0.32, but on the other hand has lower Fs of 35Hz. The OB-A15SEN has Xmax of 6mm, Qt of 0.72 and Fs of 40 Hz.


I do not use subwoofers, so I expect the woofers to play from 30-35 Hz up to 250-300Hz. There is a concern regarding the 15PR400 due to low Xmax and low Qt if it is going to perform well in this region in OB. There are however, very nice reviews of these woofers in OB, especially regarding linearity and the way it reproduces mid ranges, which is important for me. It is also more sensitive. The Pure Audio woofer was designed specifically for OB and “on paper” has certain advantages except for slightly higher Fs.



It would be interesting to hear if anyone has heard both of these speakers or could compare them face to face. I am also open for suggestions for alternative speakers.
Any info would be much appreciated.
 
#88
sismik11 said:
I guess the Skytronics no longer are available anywhere. 🙁
Click to expand...

Maybe they changed name to Skytec - the pricing seems similar, and this store still have 1 Skytronics item in their inventory.
Speaker Hardware - DJ City

I think a lot of stuff comes from the same few companies, and they slap different names on it depending on the price point. e.g. I bought a $200 "Vexus" PA speaker (junk for a workshop) from them which uses the same box as a $500 Wharfedale.

They probably made 10,000 of boxes, and put lighter / cheaper bits into 5,000 of them.
 
#89
hollowboy said:
Maybe they changed name to Skytec - the pricing seems similar, and this store still have 1 Skytronics item in their inventory.
Speaker Hardware - DJ City

I think a lot of stuff comes from the same few companies, and they slap different names on it depending on the price point. e.g. I bought a $200 "Vexus" PA speaker (junk for a workshop) from them which uses the same box as a $500 Wharfedale.

They probably made 10,000 of boxes, and put lighter / cheaper bits into 5,000 of them.
Click to expand...

Not dissimilar looking. However, it appears to have a paper cone, as opposed to polypropylene. Also, the quoted frequency range implies a much higher fs, and at 98dB/W, it almost certainly won't have the 6mm Xmax of the Skytronics. It appears to be a PA speaker.
 
#95
Bang for the buck realities!

Gotta chime in on the PE Realistic Mach 1 replacement 15"....

If you happen to have that driver, or it is the only one you can get, you can make it work. As is usual with OB bass applications, a viable solution can usually be engineered, with in the limits of the drivers potential.

However, a way better and easier to work with solution is a sister GRS driver, the 15PF-8. Can be had on sale for about $25 each (normally $31 each).

The differences between the drivers are considerable when it comes to using either one in an OB application.

The advantages of the 15PF-8 are considerable, 15PF-8 vs RSRMO-8:

Xmax: 4.0 mm vs. 2.5 mm
FS: 29 Hz vs. 22 Hz
Useable Frequency response upper limit: 2,500 Hz Vs. 1,200 Hz
QTS: 1.39 vs. .56
Unit cost: $31.00 vs. $80.00

Not knocking the RSRMO-8, it is a nice driver when used as it was designed to be used. But you are paying for features that have little value in an OB application. For $18 less than the price of one RSRMO-8 you can have two 15PF-8's. The pair of 15PF-8's wired in parallel will WAY out perform a single RSRMO.

The 15PF-8 is WAY cleaner in the mid range too. Not even close. So much simpler crossover. Speaking of which, the two 15PF-8's in parallel create a 4 ohm load, which cuts inductor requirements in half. Inductors are expensive, good ones anyway.

Another aspect is FS. To take advantage of the RSRMO-8's lower FS the baffle and or crossover correction would be considerable, both in cost and size. And even if you were to correct it to yield a flat, or near flat response down to the 22 Hz resonance, there just is not enough cone area and xmax to support a usably loud acoustic output.

There are additional differences in favor of the 15PF-8. But the above should be enough to make the point.
 
#96
Antonfazer said:
Right now I have two options, either to go with Faital 15PR400 or PureAudioProject OB-A15SEN.
I do not use subwoofers, so I expect the woofers to play from 30-35 Hz up to 250-300Hz. There is a concern regarding the 15PR400 due to low Xmax and low Qt if it is going to perform well in this region in OB. There are however, very nice reviews of these woofers in OB, especially regarding linearity and the way it reproduces mid ranges, which is important for me. It is also more sensitive. The Pure Audio woofer was designed specifically for OB and “on paper” has certain advantages except for slightly higher Fs.


It would be interesting to hear if anyone has heard both of these speakers or could compare them face to face. I am also open for suggestions for alternative speakers.
Any info would be much appreciated.
Click to expand...

Better take beyma sm115k and your faital easy suits for midbass and not for bass. In addition to this, the fatal has small xmax and for the woofer the diffuser's movement is critical and should be at least 8 in order to create the necessary pressure for the movement of the heavy diffuser. Personally, I also do not like the assertive sound of the faital, so I'm in favor of beyma.
 
#97
John Busch said:
Gotta chime in on the PE Realistic Mach 1 replacement 15"....

If you happen to have that driver, or it is the only one you can get, you can make it work. As is usual with OB bass applications, a viable solution can usually be engineered, with in the limits of the drivers potential.

However, a way better and easier to work with solution is a sister GRS driver, the 15PF-8. Can be had on sale for about $25 each (normally $31 each).

The differences between the drivers are considerable when it comes to using either one in an OB application.

The advantages of the 15PF-8 are considerable, 15PF-8 vs RSRMO-8:

Xmax: 4.0 mm vs. 2.5 mm
FS: 29 Hz vs. 22 Hz
Useable Frequency response upper limit: 2,500 Hz Vs. 1,200 Hz
QTS: 1.39 vs. .56
Unit cost: $31.00 vs. $80.00

Not knocking the RSRMO-8, it is a nice driver when used as it was designed to be used. But you are paying for features that have little value in an OB application. For $18 less than the price of one RSRMO-8 you can have two 15PF-8's. The pair of 15PF-8's wired in parallel will WAY out perform a single RSRMO.

The 15PF-8 is WAY cleaner in the mid range too. Not even close. So much simpler crossover. Speaking of which, the two 15PF-8's in parallel create a 4 ohm load, which cuts inductor requirements in half. Inductors are expensive, good ones anyway.

Another aspect is FS. To take advantage of the RSRMO-8's lower FS the baffle and or crossover correction would be considerable, both in cost and size. And even if you were to correct it to yield a flat, or near flat response down to the 22 Hz resonance, there just is not enough cone area and xmax to support a usably loud acoustic output.

There are additional differences in favor of the 15PF-8. But the above should be enough to make the point.
Click to expand...
Hi John, Can NE123W-08, 4" keep uo with two GRS 15 in parallel. Or need to go with $ 100 + drivers TB or Fostex.
Planning for an OB and need to get parts from usa, so I'm trying to get the best configurations to try.
Will a 10 mh inductor will do the job for parallel GRS 15.
Many thanks..
Johncy
 
#98
scottjoplin said:
This is also what I have found in practice, and, importantly, keeps the distortion to a minimum. OB bass has very low distortion so increasing Xmax should be something to be avoided.
Click to expand...
Hi ScottJ...

I'm trying to get a handle on this.... better understand it.

So would it be accurate to say: "Desirable would be large Xmax CAPABILITY... But small Xmax CAUSATION?

In other words...
Were you hypothetically to design/build your own large woofer... you would want a suspension etc. that PERMITS a large excursion, BUT a voice coil that does not CAUSE large excursion???
(Permits because it's inevitable to some degree with no box-resistance)

TIA for knowledge!

Greg
 
#99
That GRF-15 has a baby brother in a 12" and it looks in pix and spec to be the same as the Jaycar woofer I collected for my own big OB project that will happen one day soon [ I hope] and I have 8 of them here.
The Jaycar 12 do very well OB but can't handle much power at all and I was planning to use with subs below 40Hz
 
#100
Car woofers specifications sheets can be very seductive sometimes...
But with Mms exceeding 0.5 kG can such a driver work in vertical position?
And power handling question.
It is not clear to me whether the given power handling is measured with support of tight space inside the car or in a free space.
 
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