My MJK OB's
So I hacked together a couple of test MJK OB's. I used the FX-120 instead of the FE-103, otherwise as spec'ed by MJK). I just determined an initial amount of padding tonight to try by measurement. I have only listened to them a little and in very non-ideal circumstances as I am away from home for the summer (No tubes, laptop source, inadequate room). They appear to have lots of promise.
I have no pictures (they are just two boards and some crossover parts strewn on the floor) but I do have some measurements, taken with fuzzmeasure and a modified Rat-Shack meter (replaced electret with panasonic etc. - unsure of response above 10K) in a tiny room.
First is the FR with and without padding
So I hacked together a couple of test MJK OB's. I used the FX-120 instead of the FE-103, otherwise as spec'ed by MJK). I just determined an initial amount of padding tonight to try by measurement. I have only listened to them a little and in very non-ideal circumstances as I am away from home for the summer (No tubes, laptop source, inadequate room). They appear to have lots of promise.
I have no pictures (they are just two boards and some crossover parts strewn on the floor) but I do have some measurements, taken with fuzzmeasure and a modified Rat-Shack meter (replaced electret with panasonic etc. - unsure of response above 10K) in a tiny room.
First is the FR with and without padding
kristleifur said:
Try Hifi Kit in Stockholm, Sweden. They sell both Eminence and Fostex. I have not seen Alpha on their web page but send them a mail. They are usually helpful.
http://www.hifikit.se/index.php?id=1154
Peter
I thinking of trying out dual Alpha's with the FE167E for my fisrt OB.
What kind of effiency could I expect on the 20" baffle with two of the Alpha's?
What kind of effiency could I expect on the 20" baffle with two of the Alpha's in a u frame with a 7.5" cavity and 16" x 16" cross-sectional area?
Just wondering if I could get away with the 167 with a u frame.
BR
What kind of effiency could I expect on the 20" baffle with two of the Alpha's?
What kind of effiency could I expect on the 20" baffle with two of the Alpha's in a u frame with a 7.5" cavity and 16" x 16" cross-sectional area?
Just wondering if I could get away with the 167 with a u frame.
BR
Wow, they look very nice!
Do the stands support the speaker well enough so that it will not tip over?
Does anyone know if the the stands placed either side of the back of the woofer like that would have any effect on sound?
I'm also wondering, does elevating the speakers on spikes decrease the bass response?
Reason for asking is i'm still in the process of building mine and yours may have given me some inspiration.
Do the stands support the speaker well enough so that it will not tip over?
Does anyone know if the the stands placed either side of the back of the woofer like that would have any effect on sound?
I'm also wondering, does elevating the speakers on spikes decrease the bass response?
Reason for asking is i'm still in the process of building mine and yours may have given me some inspiration.
Hi BR,
Very neat construction; but what are the spikes supposed to do ?
Do you hear better reproduction when the spikes (gap between baffle and floor) are fitted ?
If a real advantage then why spikes instead of small blocks of felt footed wood ?
Can I suggest you jam some carpet in the gap and then suddenly pull it away whilst you are listening to some music having deep LF content ?
I suggest you will hear a loss of ambience, firmness and depth to the LF.
Cheers ....... Graham.
Very neat construction; but what are the spikes supposed to do ?
Do you hear better reproduction when the spikes (gap between baffle and floor) are fitted ?
If a real advantage then why spikes instead of small blocks of felt footed wood ?
Can I suggest you jam some carpet in the gap and then suddenly pull it away whilst you are listening to some music having deep LF content ?
I suggest you will hear a loss of ambience, firmness and depth to the LF.
Cheers ....... Graham.
Re: Re: Another satisfied customer
Hey wixy, the depth of the legs are about a inch deeper than the rear of the Eminence. I have the baffle tilted a degree or two back which help stable them, if they were 90 degrees and you have a dog or little ones it may be a problem. Would probably do something differant next time. As shallow as the legs are I don't think they are effecting anything.
Get em done, they exceded what I was expecting
.
Hey Graham, the reason for the spikes is they are being used on a carpet floor. First impressions tell me they are not lacking in the LF department. This is the kind of bottom end I was looking for, it's not real tight bass but they are very natural down low.
That would be cool. The camera I have isn't that great but I will try and take some better pics and email them to you. Thanks again.
BR
wixy said:
Hey wixy, the depth of the legs are about a inch deeper than the rear of the Eminence. I have the baffle tilted a degree or two back which help stable them, if they were 90 degrees and you have a dog or little ones it may be a problem. Would probably do something differant next time. As shallow as the legs are I don't think they are effecting anything.
Get em done, they exceded what I was expecting
. Graham Maynard said:
Hey Graham, the reason for the spikes is they are being used on a carpet floor. First impressions tell me they are not lacking in the LF department. This is the kind of bottom end I was looking for, it's not real tight bass but they are very natural down low.
MJK said:
That would be cool. The camera I have isn't that great but I will try and take some better pics and email them to you. Thanks again.
BR
Hi BR - Great Job!! 
Very nice attention to detail such as the installation of the x'overs and twisting of wire leads etc. Is the finish on the baffle a heavy use of paint - and what did you use for the baffle material - MDF or plywood? I also noticed that the Alpha woofer looks as if it may be mounted to a separate support and then butted up against the front baffle - I would suspect for mechanical isolation purposes? Details please!
I would expect a more effective coupling to the floor by having used the spikes and therefore a better base response - I like the idea but had never thought about it for use in OB. Perhaps you are listening to a little of that jazz that New Orleans is so famous for!
Very nice attention to detail such as the installation of the x'overs and twisting of wire leads etc. Is the finish on the baffle a heavy use of paint - and what did you use for the baffle material - MDF or plywood? I also noticed that the Alpha woofer looks as if it may be mounted to a separate support and then butted up against the front baffle - I would suspect for mechanical isolation purposes? Details please! I would expect a more effective coupling to the floor by having used the spikes and therefore a better base response - I like the idea but had never thought about it for use in OB. Perhaps you are listening to a little of that jazz that New Orleans is so famous for!
Thanks you sir, the paint is from home depot, it's two coats Behr pure black enamal. First coat for a primmer and filling then sanded, then second coat is applied. It's not perfect but good enough.
The baffle is just regular 18mm birch plywood. The original intent was to just build a test baffle but I wanted the 15 recessed which needed 3/8 deep cut out for this driver. I then realize this wasn't beefy enough and got creative with another piece of 18mm scrap behind the baffle. This worked out good for the legs since it allowed more surface to glue to. The legs were cut from a 20" round dropout from a past project cut into four.
These things sound great for all that jazz and more. One thing I have noticed is that bad recordings don't sound that bad on a nice OB which is one of the reasons why everyone should own one. Thanks
BR
The baffle is just regular 18mm birch plywood. The original intent was to just build a test baffle but I wanted the 15 recessed which needed 3/8 deep cut out for this driver. I then realize this wasn't beefy enough and got creative with another piece of 18mm scrap behind the baffle. This worked out good for the legs since it allowed more surface to glue to. The legs were cut from a 20" round dropout from a past project cut into four.
These things sound great for all that jazz and more. One thing I have noticed is that bad recordings don't sound that bad on a nice OB which is one of the reasons why everyone should own one
. ThanksBR
Thanks for the info BR!
IF you would want to take things up a notch you might want to check out BudP's EnABL treatment to smooth things out a bit.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100399&highlight=
I'm thinking of one of these along with the Fostex FE107 and the Alpha. Did you wind your coils or did you purchase them somewhere? What type of XO are you using in terms of slope and component values?
IF you would want to take things up a notch you might want to check out BudP's EnABL treatment to smooth things out a bit.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100399&highlight=
I'm thinking of one of these along with the Fostex FE107 and the Alpha. Did you wind your coils or did you purchase them somewhere? What type of XO are you using in terms of slope and component values?
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