Small Full Range driver selection

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planet10

planet10

frugal-phile™
Joined 2001
planet10-hifi.com
Paid Member
Abelma said:
Jeff, what kind of enclosure is that for the FX120? Is there plans available?
Click to expand...

Jeff's own Fonken-like enclosure (for the FE127, i have heard him opine that it is a bit small for FX120.

Out larger box, i have plans for it (we didn't choose the colour scheme on this one, the client did, to my mind the veneer would work better on a smaller bpx, and the red spots clash)

fonken-steen-1st-pic.jpg


dave
 
B

Bob Brines

Member
Joined 2003
planet10 said:
I was considering W4-1879, but i find it kinda ugly, so on recommendations of a couple people i got W5-1611.

dave
Click to expand...

I have a pair of these, but I haven't spent much time with them. They are a drop-in for the RS 40-1354a, but sound much better even without expensive break-in. One interesting feature is a hole around 6-7kH, so sibilance is not a problem.

Bob
 
vinylkid58

vinylkid58

Member
Joined 2005
Abelma said:
Jeff, what kind of enclosure is that for the FX120? Is there plans available?
Click to expand...

A slightly larger Fonken, with more vent area, approx. 80% of the FE127 Sd. Basically, an experiment to see how far the FE127 could be pushed to produce a little more bass. On paper, the FX120 looked looked like it would work in this box also, so curiosity took over.

PM me if you're interested in the drawings. Just be aware that this box was meant for the FE127, and would probably benefit from a slight revision for the FX120. 15mm BB instead of 12mm for starters.

Abelma said:
Do you use any BSC filter or equalization on those two driver projects?
Click to expand...

No.

jeff
 
A

Abelma

Member
Joined 2007
Hi Bob,

How you compare the TB with the Alpair7, and/or if you know also the Fostex FX120in your opinion?
Its high price is justified?
Looking for the best low freq performance, the TB seems the one?
Thx

Bob Brines said:
I have a pair of these, but I haven't spent much time with them. They are a drop-in for the RS 40-1354a, but sound much better even without expensive break-in. One interesting feature is a hole around 6-7kH, so sibilance is not a problem.

Bob
Click to expand...
 
C

chrisb

Member
Joined 2002
Abelma said:
The Gen3 Alpair 7 driver seems it has a better sensitivity response, flatter, that would say that the new genereation is less agressive for people that found a little bright on mid top?

Jeff, what kind of enclosure is that for the FX120? Is there plans available?

Thx
Click to expand...


FWIW since we've been listening to Alpair7 for over a year now, they were obviously not Gen3, but I certainly can't recall anyone commenting on over-bright top end or other issues with upper midrange - certainly not the case for some of the Fostex drivers in this size range (i.e. FE126E ).



as to Jeff's enclosure pictured - as he noted this particular pair was actually built for FE127E, and a dedicated enclosure of this format for "optimal" LF performance on the FX120 would probably need some revisiting
 
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ghw

Member
Joined 2006
If you don't want a BSC or other EQ circuit between the amp and the woofer, you have a few options, assuming you do not want your speaker to sound like a 6dB shelving low-cut filter). These are listed in order of decreasing sensibility.

1) Put the BSC at line level, before the amplifier. This could be done actively, e.g. in the feedback loop of an opamp, or passively, e.g. between a buffer like the B1 or a low-impedance source and the input of your amplifier.
2) Design a speaker to be mounted on or in a wall. This eliminates the baffle step as an issue.
3) Design the dimensions of your speaker around a wide-range driver with a conspicuous 6dB shelf at some frequency, and then choose the dimensions of your baffle around that shelf. This seems like a brutal design constraint.


You appear to be opting for either third approach (find a driver with the shelf built in) or a speaker with the low frequencies shelved down 6dB. Neither option avoids equalization of the speaker. The former approach introduces a very rigid design constraint that is unlikely to be met and the latter does terrible injury to your signal (presumably music).

Dave appears to have the best approach (use a separate woofer for the low end). If you start with a relatively high-excursion, low-efficiency mid-top, like the Scan-Speak 10f, you can then choose a woofer 6dB more sensitive and cross at the baffle step center-point to take care of BSC. Again, this could be done at line-level to avoid EQ networks in between your amps and drivers.


Cheers,
George
 
A

Abelma

Member
Joined 2007
Reading in other post about the FX120, a owner did not like him with transistor amplifier? Only when he used a tube amplifier he liked. why this could be?

http://www.diyaudio.com/forums/full-range/170874-wich-enclosure-fostexs-fx120.html

chrisb said:
well he can snatch this one now for his collection

of course he might well have (misplaced) one or two pictures of this already - wanna try and sift through that one time?


While not as pronounced as with the FE127E (or the new FF125WK) the FX 120 will definitely have that signature midrange presence/dynamics that I've not found in Alpair7.

Dave - you should try to fully break-in the WKs for a session with all 3
Click to expand...
 
A

Abelma

Member
Joined 2007
Thank you for your opinion George.
But I will stick with the idea of one driver in this project.

ghw said:
If you don't want a BSC or other EQ circuit between the amp and the woofer, you have a few options, assuming you do not want your speaker to sound like a 6dB shelving low-cut filter). These are listed in order of decreasing sensibility.

1) Put the BSC at line level, before the amplifier. This could be done actively, e.g. in the feedback loop of an opamp, or passively, e.g. between a buffer like the B1 or a low-impedance source and the input of your amplifier.
2) Design a speaker to be mounted on or in a wall. This eliminates the baffle step as an issue.
3) Design the dimensions of your speaker around a wide-range driver with a conspicuous 6dB shelf at some frequency, and then choose the dimensions of your baffle around that shelf. This seems like a brutal design constraint.


You appear to be opting for either third approach (find a driver with the shelf built in) or a speaker with the low frequencies shelved down 6dB. Neither option avoids equalization of the speaker. The former approach introduces a very rigid design constraint that is unlikely to be met and the latter does terrible injury to your signal (presumably music).

Dave appears to have the best approach (use a separate woofer for the low end). If you start with a relatively high-excursion, low-efficiency mid-top, like the Scan-Speak 10f, you can then choose a woofer 6dB more sensitive and cross at the baffle step center-point to take care of BSC. Again, this could be done at line-level to avoid EQ networks in between your amps and drivers.


Cheers,
George
Click to expand...
 
C

Chaz H

Member
Joined 2009
Abelma said:
Hi Bob,

How you compare the TB with the Alpair7, and/or if you know also the Fostex FX120in your opinion?
Its high price is justified?
Looking for the best low freq performance, the TB seems the one?
Thx
Click to expand...
I can't speak to the bass performance of the other drivers, but my W5-1611s do pretty well in the double bass reflex enclosures I made for them. I test them out using James Blake's cover of "Limit to your Love" which features a deep, oscillating bass line. They get overwhelmed but they try damned hard to make the room shake! If specs are to be trusted then they can be coaxed down to about 45Hz. the DBR cabinet is intended to reduce their excursion requirements, which I think is a good idea for any full range driver.

But if you search for FX120 you'll find someone who made a bookshelf horn for those drivers recently, and IIRC was achieving some 30hz extension. So bass response is often a function of the time and space you're willing to sacrifice.

Bob, any chance you would post the frequency response and TS parameters for the W5 drivers? Without testing equipment I'm doomed to trust my own ears. :confused: I'm interested in trying to understand better what it is my own drivers might be doing.
 
A

Abelma

Member
Joined 2007
Hi All.....I am reading on others forums to get some idea of the characteristics of those drivers and others as the Jordan JX92 (Out of my project budget). A 5"will not be suitable for me if the max exterior diameter is more than 140 mm because a possibility is to use this driver in a enclosure under the TV, and I have some space limit to build the cabinet. But, that will be after some experimentation with a proper cabinet for the driver, and may be that will be the final destination, don't know yet.

I am looking very well the TB W4-1879 and I like the Fs of 55 Hz and the Xmax of 5 mm. If the parameters are right it is an excellent candidate. The only thing is that I am looking not only good potential bass performance. The Jordan JX92 with excellent reviews on the forums has very close parameters.
Bob, it seems that you have some listening with this driver, so I am anxious to know you opinion.

After the driver is selected I will start another thread to have help on the enclosure selection and I am very interested to learn and do my own simulations and design. It seems that Martin King or MJK has a good software simulation.
More and more I am reading about TL loudspeaker, more and more interested to do it myself or DIM :)

I appreciate the people here helping me to find the driver, I think that everyone was where I am sometime. Thank you.
 
G

ghw

Member
Joined 2006
Abelma,

I'm sorry if I suggested some things you didn't want to do. One driver isn't necessarily a problem.

Is your television mounted on or against a wall? If so, that space might lend itself to eliminating the need for bsc, if the driver is radiating into 2pi space over its whole range of operation. Just watch out for nearby cavities and sharp edges, which cause resonances and diffraction, respectively.

MJK's software is excellent, and more than worth the price of admission.


George
 
A

Abelma

Member
Joined 2007
Hi George, don't worry, it is always useful to know experiences, and I was nnot so clear with my requirements, thx.

The enclosure under the Tv could be the last destination for those drivers. For now the idea is to build a nice pair of enclosure in a std position on the room.
 
DYNABLASTERTUNERS

DYNABLASTERTUNERS

Member
Joined 2009
No Maaaaaaan, that's Frodos Project (Herr der Ringe = Lord of the Rings :D )

should be a good driver, but I haven't heard them

but I have Tang Band W5-1611 that don't need notch(for my taste) and no BSC in this TML Enclosure:
Flat 5 Bausatz - Lautsprecher Selbstbau by blue planet acoustic
Sound is mellow never fatiquing, Vocals are very real, and the cone is big for 5" Wideranger and no need for a tweeter(also for my taste)

that Flat 5 TML has more Bass then this 10L BR "Sarah" that is more balanced, but "Sarah" has BSC and notch filter
http://www.roehren-und-hoeren.de/phpBB/viewtopic.php?t=6037
Sarah Thread:
http://www.hifi-forum.de/viewthread-267-8.html
altough it's all room dependent...
 
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