These really are too big for my tiny "speaker corner" but still probably a better fit than the last couple of resident pairs (Martin Logan SL3 and Polk SRS-SDA-3.1TL). Screwing an additional "bass reflector" plate to the bottom means I can pull them out on to my carpeted floor too should the desire strike me.
Compared to the original "2.8mkII" that I built first these DO have a better developed bottom end, the goal I was after. It's still not ultra-deep and may never be there but certainly a significant improvement, really only showing it's roll off on certain tracks, electronica mostly, that I know have a palpable bass presence... a prime example is the bass riff that comes in at about 20 seconds in Crystal Method's "PhD": YouTube - The Crystal Method - PhD
These speakers will convey most of that song but the very bottom dip in that specific bass riff is notably more rolled off than the slightly higher section that precedes it. Not sure exactly where in the freq range that would be but I'm guessing under 40Hz anyway.
This metronome build also seems to have slightly decreased their efficiency, now requiring just slightly more on the big knob to produce the comfortable listening levels that I grew used to with the 2.8mkII.
Imaging is not really less or more but rather different, due I'm sure in no small part to the slight tilt of the drivers and the shape of my room. On one track (I don't remember which) my wife actually stood on a chair in the back corner of the room so she could put her ear next to one of our Klipsch SS1 surround speakers and thus verify that the full image we were hearing was coming *only* from the metronomes in front! It is spooky how good these can throw sound in our room with the right track. Conversely "toe in" is a much more finicky matter with these to get that same "center stage disappear into the room" effect that the smaller 2.8mkII bass reflex cabs produced so effortlessly. I really think in a larger room, with more space to spread them apart, placing these "metros" wouldn't be such a task either but in their default placement (as photographed) they take a good deal more fine tuning for the sound stage to fully materialize.
So there you are, flatter throughout the whole frequency range with a more extended lower end, but also needing more room, a bit more power, and careful placement to sound their best compared to the CSA 2.8mkII.
If nothing else these have shown me that the 2.8mkII that I built previously, a speaker some have said "should be spectacularly mis-tuned" really aren't that bad after all. With the right sub, something I'm shopping for again myself, mostly for home theater use, either pair could be quite good, the larger metros simply needing less augmentation to pull of their magic... in fact my little, although extremely well made, 7" sealed "Edge Audio" powered subwoofer does almost nothing to add to the metronome's bass end and for two channel music I don't miss it at all.
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For it to "sound like" it is coming only from the speakers, you would be avoid early reflections. 8" drivers will beam in the treble which may be seen as an advantage in that respect. To benefit further, you might consider turning the speakers at an angle out from the corners so the walls see the sides of them, and yes, experiment with pulling them out a little. I suggest this from a treble point of view despite the trade-off that the bass presents.
FWIW, the 2.8MKII is actually pretty badly mistuned. Using the AN10's, with measured TS params, the as built box has a nasty peak at ~75Hz and not much below. The real issue is the 6" hole (big port). I hate to call it a port. However, there is a simple fix. Using a 3" x 9" long port instead of the hole will result in flat response with an F3 of ~45Hz. Box size is actually ok for the as measured AN10. Can't say for the AN8.
So, the port/ports are not correct but can be easily fixed.
So, the port/ports are not correct but can be easily fixed.
Last summer’s project was supposed to be a pair of FE167e Metronomes. Having already made Mets with FE108eSigma and F120A drivers, I wanted to hear what a 6.5” driver could do in this style enclosure. (I obviously like the performance of this enclosure, and my wife finds them attractive--although she is growing concerned about the total number of speakers in the house.) The 2010 building season was instead taken up with making kitchen cabinet doors--a worthy endeavor to be sure, and one which earned some serious points for me.
I did break in the 167’s last year in an OB set up, so they have more than 400 hrs on them, and will only need a few more to ‘wake’ them up.
I ran the numbers from Dave Dlugos' Metronome tables in MJK’s MathCAD worksheets and tried tweeking the dimensions to see if anything looked more appealing. The box dimensions (generated by Scottmoose IIRC) appear optimal, but I decided to try a port length of 3” rather than 2”. It’s easy enough to trim the port down if I don’t like what I hear with the 3” length. This should give a couple Hz extension on the low end with only a small change in the bass output SPL.
So I have been working away for about 2 months now. Only final finish left coats left to go. Pics below show the 167's breaking in (sitting next to my MKJ OBs) and what they looked like a few days ago before I put oak veneer on the front baffles. This is to hide the edges of the ply. I cover the entire baffle because I use a round-over on the edges for cosmetic reasons, and I don’t like the look of exposed plys.
I did break in the 167’s last year in an OB set up, so they have more than 400 hrs on them, and will only need a few more to ‘wake’ them up.
I ran the numbers from Dave Dlugos' Metronome tables in MJK’s MathCAD worksheets and tried tweeking the dimensions to see if anything looked more appealing. The box dimensions (generated by Scottmoose IIRC) appear optimal, but I decided to try a port length of 3” rather than 2”. It’s easy enough to trim the port down if I don’t like what I hear with the 3” length. This should give a couple Hz extension on the low end with only a small change in the bass output SPL.
So I have been working away for about 2 months now. Only final finish left coats left to go. Pics below show the 167's breaking in (sitting next to my MKJ OBs) and what they looked like a few days ago before I put oak veneer on the front baffles. This is to hide the edges of the ply. I cover the entire baffle because I use a round-over on the edges for cosmetic reasons, and I don’t like the look of exposed plys.
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Steve,
I'm grateful to you for having such a good idea! And grateful to you, Scott, and Dave for making it possible for me to build three really sweet speakers! The FE108eSigma Met is where I got my start in speaker building. And the Met is the only design I have repeated. The question now is: will I go for four? (or more?)
Cheers, Jim
I'm grateful to you for having such a good idea! And grateful to you, Scott, and Dave for making it possible for me to build three really sweet speakers! The FE108eSigma Met is where I got my start in speaker building. And the Met is the only design I have repeated. The question now is: will I go for four? (or more?)
Cheers, Jim
The FE167e Metronomes are finished! The pic below shows one of them standing in front of a FE108eSigma Met (my first build). I don’t think I will build a Met with larger drivers than the 167--these still have that svelte, high WAF character. With larger drivers, I think they would begin to look bulky and awkward.
After about 20 hrs. of playing (to wake up the drivers from their slumbers, even though they had more than 400 hrs. on them already,) I began critical listening. They naturally have a more bass extension than the 108’s, and even a bit more than the F120A Mets. I plan to make a simple cardboard tube port 2” long to see if I prefer them as Scott designed them, or if I will leave the ports at 3”. I need to make measurements, but from the sound of tacks like “Temple Caves” from the CD Planet Drum, I believe they have useful output into the mid 30 Hz range. The deepest notes are not as strong as they should be (and would be with subwoofer giving extension flat to 30 Hz or lower,) but definitely there and palpable.
The freq. balance wasn’t right though. A little too detailed and ‘hot’. So I ran a quick BSC calc using the Excel sheet from Quarter Wavelength Loudspeaker Design and got the following numbers:
for 2 dB of BSC: 0.5 mH and 1.8 ohms;
for 3 dB of BSC: 0.8 mH and 2.9 ohms.
I happen to have 0.7 mH air core inductors and 1.5 ohm Mills resistors. Adding these to the 167 Mets gives a satisfactory result. Still lively, yet not fatiguing.
More listening and testing will have to wait. Our grandsons are now here for a week. Delicate and vulnerable items must be put away. Little ones can’t be expected to be careful and cautious for long periods of time!
Cheers, Jim
After about 20 hrs. of playing (to wake up the drivers from their slumbers, even though they had more than 400 hrs. on them already,) I began critical listening. They naturally have a more bass extension than the 108’s, and even a bit more than the F120A Mets. I plan to make a simple cardboard tube port 2” long to see if I prefer them as Scott designed them, or if I will leave the ports at 3”. I need to make measurements, but from the sound of tacks like “Temple Caves” from the CD Planet Drum, I believe they have useful output into the mid 30 Hz range. The deepest notes are not as strong as they should be (and would be with subwoofer giving extension flat to 30 Hz or lower,) but definitely there and palpable.
The freq. balance wasn’t right though. A little too detailed and ‘hot’. So I ran a quick BSC calc using the Excel sheet from Quarter Wavelength Loudspeaker Design and got the following numbers:
for 2 dB of BSC: 0.5 mH and 1.8 ohms;
for 3 dB of BSC: 0.8 mH and 2.9 ohms.
I happen to have 0.7 mH air core inductors and 1.5 ohm Mills resistors. Adding these to the 167 Mets gives a satisfactory result. Still lively, yet not fatiguing.
More listening and testing will have to wait. Our grandsons are now here for a week. Delicate and vulnerable items must be put away. Little ones can’t be expected to be careful and cautious for long periods of time!
Cheers, Jim
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OK, final report:
After extended listening with many types of music, I have settled on a BSC of 0.7 mH and 2.2 ohms. On audiophile material, I like the 1.8 ohms, however, just a little more off the top works better overall. I switched out the 1.5 ohm Mills resistors for L-pads to supply variable resistance so I could obsessively tweek the BSC. You can drive yourself crazy adjusting the BSC for each album in order to obtain maximum performance, but I don’t want to live like that in the long run!
Bass tuning: I made the port tubes 3” long instead of 2” based on how the MathCAD model looked--the 3” tube would give a few more Hz on the bottom end at the expense of maybe 1 dB lower output. So I tried 2” long ports made from cardboard just to compare. Result: essentially no difference from the 3” tubes.
That being the case, I will leave the ports at 3” long. No reason to bother changing them.
I also tried the ‘bearded whizzer’ tweek. I placed a small amount of PE AccoustaStuff around the whizzer (see photo) to see if it would result in reducing the touch of high freq harshness produced by interference between the whizzer and the main cone. Both my wife and I agree that this makes a small, but worthwhile improvement.
Conclussions:
The FE167e Mets are a success! They give up a bit in the mids & highs compared to the FE108eSigma and F120A drivers. OTOH, they hit deeper, play louder, and handle complex, large scale classical music better than their smaller siblings.
Problem: I now have three pairs of Mets and the OBs (using FF85K and Alpha 15) for this room. (The living room has the FE127e Fonkens Prime--and they won’t be moved. No other large spaces are available.) I can’t bring myself to part with any of them, yet they don’t all fit in the room. And then there is next year’s project in the planning stage.
After extended listening with many types of music, I have settled on a BSC of 0.7 mH and 2.2 ohms. On audiophile material, I like the 1.8 ohms, however, just a little more off the top works better overall. I switched out the 1.5 ohm Mills resistors for L-pads to supply variable resistance so I could obsessively tweek the BSC. You can drive yourself crazy adjusting the BSC for each album in order to obtain maximum performance, but I don’t want to live like that in the long run!
Bass tuning: I made the port tubes 3” long instead of 2” based on how the MathCAD model looked--the 3” tube would give a few more Hz on the bottom end at the expense of maybe 1 dB lower output. So I tried 2” long ports made from cardboard just to compare. Result: essentially no difference from the 3” tubes.
That being the case, I will leave the ports at 3” long. No reason to bother changing them.I also tried the ‘bearded whizzer’ tweek. I placed a small amount of PE AccoustaStuff around the whizzer (see photo) to see if it would result in reducing the touch of high freq harshness produced by interference between the whizzer and the main cone. Both my wife and I agree that this makes a small, but worthwhile improvement.
Conclussions:
The FE167e Mets are a success! They give up a bit in the mids & highs compared to the FE108eSigma and F120A drivers. OTOH, they hit deeper, play louder, and handle complex, large scale classical music better than their smaller siblings.
Problem: I now have three pairs of Mets and the OBs (using FF85K and Alpha 15) for this room. (The living room has the FE127e Fonkens Prime--and they won’t be moved. No other large spaces are available.) I can’t bring myself to part with any of them, yet they don’t all fit in the room. And then there is next year’s project in the planning stage.
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Problem: I now have three pairs of Mets and the OBs (using FF85K and Alpha 15) for this room. (The living room has the FE127e Fonkens Prime--and they won’t be moved. No other large spaces are available.) I can’t bring myself to part with any of them, yet they don’t all fit in the room. And then there is next year’s project in the planning stage.
Time to upsize, you need a bigger house with more rooms so you can build more speakers.
Martin
My mets gave me the same feeling. One thing to remember with BSC is the compensation does some EQ but the fundamental radiation angle transition remains. The met cabinet has its benefits on the inside. If I were you I'd alter the front baffle to find the sound I was after.
Hi Bob,
Glad to hear that you are happy with the MTs.
It was hearing your HCs that resulted in my building a pair for the kids. The HCs do a great job and can fill a large space with wonderful sound. Maybe you can do what I did and give the HCs to your kids (or other relatives.) They make a really nice gift!
Cheers, Jim
Glad to hear that you are happy with the MTs.
It was hearing your HCs that resulted in my building a pair for the kids. The HCs do a great job and can fill a large space with wonderful sound. Maybe you can do what I did and give the HCs to your kids (or other relatives.) They make a really nice gift!
Cheers, Jim
I've just finished the design, with Scott's help, for a 5ft tall Metronome based on the new Fostex FF225WK.
Five years on from the first one however, I will not be building it myself. My mate Colin will be doing the cabinet for me.
American black walnut finish with a FT17H (with LPad) to fill in the very top.
This speaker project was my wife's idea as she wanted a good looking speaker in the room once more, and she's paying, so who am I to argue
Watch this space
Five years on from the first one however, I will not be building it myself. My mate Colin will be doing the cabinet for me.
American black walnut finish with a FT17H (with LPad) to fill in the very top.
This speaker project was my wife's idea as she wanted a good looking speaker in the room once more, and she's paying, so who am I to argue
Watch this space
Hi Steve,
After building the FE167e Mets, I don't think I would go for a larger driver. The cabinet starts to get large, and the effort to construct it increases exponentially with size! And I'm not feeling the need for a larger driver in our modestly sized rooms.
Is Colin building the cabinets because he has bigger/better tools or is it a matter of convenience?
I will be eager to hear how your project progresses.
Cheers, Jim
After building the FE167e Mets, I don't think I would go for a larger driver. The cabinet starts to get large, and the effort to construct it increases exponentially with size! And I'm not feeling the need for a larger driver in our modestly sized rooms.
Is Colin building the cabinets because he has bigger/better tools or is it a matter of convenience?
I will be eager to hear how your project progresses.
Cheers, Jim
Hi Jim
Colin has better tools and a lot more cabinet building skills than I do.
The larger driver is simply because I want to shift more air.
At the moment I am using 3.5 feet high by 18 inch wide open baffles with 12 inch wide-range main drivers,
backed up by 12 inch bass units driven actively, plus a super-tweeter of course.
TBH they are too big for the room, but boy do they sound solid, weighty and dynamic! if lacking some subtlety.
I want to retain some of this characteristic sound with smaller speakers and add in a bit more finesse,
hence the reason for the bigger Met. Compared to the baffles, those tall, slim cabinets will be far less visually intrusive.
Gychang
Thanks for that. I have fond memories of those original cabinets.
I felt like a pioneer in those days, working in my basement, without the aid of MJKs software tools.
It'll be nice to get back into doing Mets.
BTW I liked the striking visuals on your original Mets; a "happy accident" IIRC
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FE 166En Metronome Dimensions
Anyone tried the Planet10 FE-166 drivers in a Metronome configuration? I've gotten WAF for the 60" tall metronomes over the 48" tall ones so i'd like to move forward with these but i notice the tables only show the FE-167 dimensions. Since these have different specs what would the dimensions be for the Fe-166En's from Planet10?
Anyone tried the Planet10 FE-166 drivers in a Metronome configuration? I've gotten WAF for the 60" tall metronomes over the 48" tall ones so i'd like to move forward with these but i notice the tables only show the FE-167 dimensions. Since these have different specs what would the dimensions be for the Fe-166En's from Planet10?
Sherpa,
Before I built my pair of FE167e Mets, I looked at the FE166e to see how they would work in a Met. Models in MJK's MathCAD worksheets lead me to conclude that I should grab a pair of FE167e before they disappeared, rather than using the 166's.
When I saw your question, I wondered about the recently released FF165WK. When I modeled it in a Met with the dimensions for the FE167e, it appeared to be useable, but could stand to be improved. So today I had a little time & ran some models of the FF165WK in a slightly smaller cabinet than the FE167e. Below is about the best I found in my limited time. Scott can probably do better.
Using MJK's MathCAD worksheets where:
L= 60"
Z(d)= 30
S(0)= 4"x2"
s(l)= 9"x6"
port dia= 3"
port L=4"
Note: I did not check to see if the drivers actually FIT into this cabinet, so if you decided to use these dimensions: make careful drawings to check everything first!!!
Cheers, Jim
Before I built my pair of FE167e Mets, I looked at the FE166e to see how they would work in a Met. Models in MJK's MathCAD worksheets lead me to conclude that I should grab a pair of FE167e before they disappeared, rather than using the 166's.
When I saw your question, I wondered about the recently released FF165WK. When I modeled it in a Met with the dimensions for the FE167e, it appeared to be useable, but could stand to be improved. So today I had a little time & ran some models of the FF165WK in a slightly smaller cabinet than the FE167e. Below is about the best I found in my limited time. Scott can probably do better.
Using MJK's MathCAD worksheets where:
L= 60"
Z(d)= 30
S(0)= 4"x2"
s(l)= 9"x6"
port dia= 3"
port L=4"
Note: I did not check to see if the drivers actually FIT into this cabinet, so if you decided to use these dimensions: make careful drawings to check everything first!!!
Cheers, Jim
Attachments
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Pressure to get his PhD thesis done is going to keep Scott from us for at least a while. He did say much the same thing over Skype today, and will look into it for me.
Jim, your sim looks good. Mets are fairly tolerant so yours is likely good to go.
I just ordered a pair of FF165wk today (and 20 FF85 & 2 pair of 125)
dave