Novice questions re: 1st DIY full range project - existing cabinets

[rbclark]

Hello all,

1st time poster working on my 1st DIY speaker project. I've really enjoyed reading your knowledgeable posts. But there's so much to learn! I usually try not to post questions that have been answered before, but I've read so much here I'm really uncertain of my plan so I thought I'd try and give you as much info about my situation as possible and ask for your opinions.

Got my 1st taste of good hifi about 25 years ago when my cousin had McIntosh amp/preamp with Dahlquist DQ-10s. Over the years, I've only been able to afford a little gear here and there: B&K amp/preamp; Audio Alchemy DAC; Cambridge Audio CD. Never had any tubes, but I'm interested based on the reviews I've read. My interest has resurged lately finding that I don't have to spend much to get some pretty good sounding gear - Trends Audio TA-10.1; SqueezeBox playing FLACs from my computer; and DIY speakers!

I like what I've read about full range drivers. I like the idea of minimal stuff between source & speaker and I'm anxious to hear it.

Music I like:
Diana Krall - Love Scenes - wow! I like the bass and the vocals most. While I like *some* jazz, I'm more into Weather Report, Bob James, Lee Ritenour, etc than Duke Ellington, etc.
Almost anything acoustic (especially guitar)
I prefer simple music where there are not a lot of instruments playing at once.

So far the project plan is:
Drivers - Fostex FE167E full range (these will be here next week); Specs:
Was going to use the Hemp Acoustics FR6.5C - but it's backordered.
Dayton BPA-38G HD Binding Post Pair Gold
2 inch adjustable port. (6 to 11 inches)
Damping material that came out of the Mordaunt Shorts. Gotta read some more to figure out how much to stuff where.
Internal wiring - Walmart Yardmaster
Speaker cables - Walmart Yardmaster

Room is 14 x 19 ft. Ceiling is 8 ft.

Cabinets are Mordaunt Short MS-300. External size (inches): 21h x 9w x 9d. Front holes are 5.75 inches diameter. The hole in the back is almost 2 inches diameter. It was covered by the crossover board - speaker terminals on the back. These speakers are in the neighborhood of 20 years old. I think they've suffered terribly in the attic during some periods when we couldn't have them in the house. The N.E.A.R A8Ts sound much better than the Mordaunt Shorts - although they lack in bass. The N.E.A.R. A8T's are temporary. Gonna put 'em on the back porch once this project is complete.

Here are some pictures to give you an idea of the cabinet layout: http://www.smugmug.com/gallery/3327923

My questions are:
1 - What's the easiest way to deal with the baffle? I'm thinking I'll cut it out & replace it entirely.
2 - Can the port be on the back? If so, I could use the existing hole that was used for terminals. If not, should I just cover the existing with a piece of plywood?
3 - I'm not confident that I've fed the parameters correctly to any port calculators, but I've come up with 2 inches in diameter and 6.25 inches long. I'd really appreciate some confirmation/correction on this.
4 - Driver placement? I thought I'd like to put it where the top hole is now - ear level.
5 - I'm assuming my cabinet is big enough. Is it? I figured I'd 1st try to make this work and then build some custom cabinets if this doesn't work out.
6 - And finally, have I made any major mistakes - yet? Can this work? I'm hoping it will sound better than anything I've ever had.

Thanks for your help!
Bob

 

[gychang]

Music I like:
Almost anything acoustic (especially guitar)
I prefer simple music where there are not a lot of instruments playing at once.

I'm hoping it will sound better than anything I've ever had.

Thanks for your help!
Bob

Bob: you sound like me when I started to build fullrange speakers.
If u have 167E coming, BIB is very SIMPLE to build and my understanding is excellent with your speakers.

http://www.zillaspeak.com/bib.asp

gychang

 

[rbclark]

Re: Re: Novice questions re: 1st DIY full range project - existing cabinets

Bob: you sound like me when I started to build fullrange speakers.
If u have 167E coming, BIB is very SIMPLE to build and my understanding is excellent with your speakers.

http://www.zillaspeak.com/bib.asp

gychang

The BIB does look like one of the easier ones to get right. From the discussion here, it almost seems like it just works regardless! I'll definitely be considering it if I don't get the thumbs up from others here on whether I may have some success with my existing cabinets.

Thanks a lot for the suggestion.
Bob

 

[loninappleton]

I have built the BIB and am enjoying that. But I also made an MLTL
and think that is very good. I have one of each going at the moment.

Others here will say I'm nuts.

Try to minimize your work load when you can. There's a lot of expertise here on scratch building and also modelling the builds designed
by Scottmoose, GM and others.

I would like to move from the BIB build to the Spawn-Harvey. All this is on the full range threads here.

To sum up, I'm sold on the larger cabinet designs. You can retrofit an older cabinet but the dimensioned builds for your driver will give a better result.

 

[rbclark]

I would like to move from the BIB build to the Spawn-Harvey. All this is on the full range threads here.

To sum up, I'm sold on the larger cabinet designs. You can retrofit an older cabinet but the dimensioned builds for your driver will give a better result.

I really like the looks of those Spawns of Frugel. Looks like the Iris was designed with my FE167E drivers in mind. I'm giving this some serious consideration. Though I'm not a carpenter, I'm obviously not a speaker designer either. Seems I'm going out on a limb trying to stick the FE167E's into my old cabinets - might just be a waste of time.

Thanks!
Bob

 

[planet10]

Cabinets are Mordaunt Short MS-300. External size (inches): 21h x 9w x 9d.

If the walls are 3/4" that comes out to a gross volume of just shy of 18 litres

1 - What's the easiest way to deal with the baffle?

Easiest is to just put a new baffle over the old, vut if you do cut the old one out you can add some bracing

2 - Can the port be on the back?

sure

3 - I'm not confident that I've fed the parameters correctly to any port calculators, but I've come up with 2 inches in diameter and 6.25 inches long. I'd really appreciate some confirmation/correction on this.

We did a 15 litre FE167 BR... the 2" D port was 2.5" long so i'd expect that yours should be close to this length.

4 - Driver placement? I thought I'd like to put it where the top hole is now - ear level.

That's where i'd put it.

dave

 

[loninappleton]

I really like the looks of those Spawns of Frugel. Looks like the Iris was designed with my FE167E drivers in mind. I'm giving this some serious consideration. Though I'm not a carpenter, I'm obviously not a speaker designer either. Seems I'm going out on a limb trying to stick the FE167E's into my old cabinets - might just be a waste of time.

Thanks!
Bob

OTOH (On the other hand) there's the curiosity factor of a first build.
I started out by modding cabinets (with some advice from GM).

You have the parts-- adjustable port and so on.

Simply making a new front baffle would give practice in circle cutting
without much spoilage if something goes amiss. Then if you have an
A/B comparison (old versus new) you'll be able to hear the difference with just one completed mod.

Have you listened to the FE167's in free air? (put one up agains ta pillow or something) to see how that sounds. Cur a hole in a big piece and that would give the open baffle effect. Trim the OB and you have your new front for the old cabinet.

One other thing: Break in. I've used the method of putting the
drivers in a closed box well stuffed and bolted face to face, tune the tuner to an unused frequency to get white noise and let them run someplace where jacking up the volume won't drive anyone nuts. The white noise exersizes the cone during the break in. The wiring is one push and one pull.


To check to make sure your speaks are coded correctly, wire one up
with 2 leads. The leads are then attached to a small battery --
C or D cell will do. You'll hear the speaker pop and the cone will move
forward or if reversed, backward. The push and the pull.

Anybody else can come in and correct me on this. I did the procedure years ago.

 

[rbclark]

Dave, L,

Thanks for your comments. I was hoping the existing cabinets were worth a try. I'm definitely going to follow through with it - but I'm already thinking about the Spawn Iris project next.

Funny - I thought maybe... just maybe... I would submerge into the DIY custom speaker building world just long enough to restore good sound to these old cabinets at a one-time expense as opposed to becoming a tweaking perfectionist with a regular speaker budget. Yet, here I am with 2 projects lined up before I even get the 1st one under construction! And you can bet that as soon as I stumble across the budget tube amp (easy kit? pre-built?) that gets the diyAudio seal of approval that'll be project #3!
Thanks guys! I'm really looking forward to it!

L,
As far as the break-in suggestion, are you saying that sometimes the driver terminals come improperly marked?

Thanks,
Bob

 

[gychang]

Dave, L,

Funny - I thought maybe... just maybe... I would submerge into the DIY custom speaker building world just long enough to restore good sound to these old cabinets at a one-time expense as opposed to becoming a tweaking perfectionist with a regular speaker budget. Yet, here I am with 2 projects lined up before I even get the 1st one under construction! And you can bet that as soon as I stumble across the budget tube amp (easy kit? pre-built?) that gets the diyAudio seal of approval that'll be project #3!
Thanks guys! I'm really looking forward to it!

Bob, this is not good. Typical symptom of CUIDIY syndrome. (caught up in DIY). I have the same disease, be careful.

gychang

 

[loninappleton]

[
L,
As far as the break-in suggestion, are you saying that sometimes the driver terminals come improperly marked?

Thanks,
Bob [/B]

It's far from common. The proper term is having the speakers in
phase, I believe.

But the battery test is printed in beginner speaker books and is
well known.

Using the battery test also illustrates the Xmax of the speaker-- how far the cone travels

Lon

 

[planet10]

Funny - I thought maybe... just maybe... I would submerge into the DIY custom speaker building world just long enough to restore good sound to these old cabinets at a one-time expense as opposed to becoming a tweaking perfectionist with a regular speaker budget. Yet, here I am with 2 projects lined up before I even get the 1st one under construction!

muhaha

Another addict in the making...

And you can bet that as soon as I stumble across the budget tube amp (easy kit? pre-built?) that gets the diyAudio seal of approval that'll be project #3!

Kit (aimed squarely at the beginner)

<http://www.bottlehead.com/et/adobespc/paramourII/paramourII.htm>

this is one that a lot of people do as a starter because the entry is so low. There are at least 4 variations

http://www.tubedepot.com/diy-k12m.html
http://www.tubeaudio.com/page23.html
(the monobloks) http://www.tubedepot.com/diy-k11m.html

and some user builds
http://diyaudioprojects.com/Tubes/K-502-Tube-Amp-Kit/index.htm
http://diyaudioprojects.com/Tubes/K-12M/K-12M.htm

a little more ambitious

http://www.diyhifisupply.com/diyhs_joplin.htm

and if you want a pre-built amp, this one is probably the pinnacle of SE EL84s.

http://www.vaughnaudio.com/carina.html

These guys supply someof the better "pre-built kits"
http://www.divertech.com/antiquesl.html

and here is a laundry list (showing the bewildering choices available)
http://www.worldtubeaudio.com/directory/categories/kategorie_8.htm

and for every kit there are probably 10 fairly well documented diy builds.

As far as the break-in suggestion, are you saying that sometimes the driver terminals come improperly marked?

Not often on a product like Fostex (i've never found a set mislabeled). You will find that not all manufactures use the convention that positive to red pushes the cone out thou.

dave

 

[seventenths]

RBC,
Funny isn't it? I started along this path with similar goals. To this date, I have built a CMOY headphone amp (It didn't LOOK like bait ), then a gainclone, then a Bottlehead S.E.X amp (excellent kit) then a set of BiBs and now I'm in the middle of a scratch-built tube preamp. A Nelson Pass amp and a set of Hemp fr8 SpawnOFH cabinets are on the short list of coming projects but the list seems to grow as if it were alive...

I get an insane level of gratification from this new hobby


Good luck with your decision...


7/10

 

[rbclark]

Bob, this is not good. Typical symptom of CUIDIY syndrome. (caught up in DIY). I have the same disease, be careful.

gychang

I'm predisposed to getting CUI. Should be no surprise that I now get CUIDIY. Thanks for the diagnosis.

 

[rbclark]

muhaha

Another addict in the making...



dave

Dave,

I thank you for your tube amp suggestions.... and my wife thanks you!

Bob

 

[rbclark]

Uh oh....

Got the drivers today. Got one installed and it sounds terrible. Any bass causes a very bad distortion. Anything else is ok - but I'm not sure how ok at this point. This couldn't be a break-in thing... I don't think.

Here's what I did:

The driver is installed in the top hole of the existing cabinet. Turns out that it fit the hole w/out modification. (The hole is 5.75" and the driver's specified baffle hole diameter is 6" - go figure). Could this be a problem? The cone is not restricted in any way I don't think?

The original bottom driver is out so right now there's a 5.75" diameter hole in the front baffle. I tried re-installing the original driver (to cover up the hole - probably not the most rigid speaker structure!) but it didn't make any difference.

I've not installed the port tube yet. So there's also a 2" hole in the back.

Could my problem be due to the open cabinet? I'm doubting it. If this driver could not distort in an open baffle design, seems it wouldn't distort here. I'll close up the cabinet tomorrow night to see if that makes a difference. I fully intended to - I just thought I'd give it a quick listen before I finished.

I'd appreciate any thoughts on where I've gone wrong.

Thanks for your help!
Bob

 

[planet10]

so right now there's a 5.75" diameter hole in the front baffle ... a 2" hole in the back.

No bass -- and easily overloaded in that region -- is to be expected. And you do need to quickly get at least 100 hrs on them (face-to-face out of phase with interstaion FM (muting off) is a good way to get them going.

dave

 

[rbclark]

No bass -- and easily overloaded in that region -- is to be expected. And you do need to quickly get at least 100 hrs on them (face-to-face out of phase with interstaion FM (muting off) is a good way to get them going.

dave

I guess I was expecting some "missing bass" - but not "overloaded". In hindsight, I don't know why I should expect lower frequencies to just disappear - I guess it makes sense that they sound bad. I'm surprised though that anyone would be happy with this as a full range solution.

What I've got is pretty un-listenable. Is there something I can do to prevent the overloading? Or, are you suggesting that this could be a break-in thing? I'd love to think this will go away with some time.

Thanks for the help!
Bob

 

[planet10]

Is there something I can do to prevent the overloading?

Cover/seal the other driver opening and install your port in the back (i'm guessing 2.25-2.75" long)

dave

 

[loninappleton]

Cover/seal the other driver opening and install your port in the back (i'm guessing 2.25-2.75" long)

dave

Dave, others, I have a question here. If he just puts the speaker
back in the hole as a cover is that other driver acting as a passive radiator? It's my understanding that a passive radiator is a speaker frame with no magnet structure.


Rb,

Also for the Fostex driver, start with no internal stuffing. I have the
MLTL design for Fostex 127e with practically nothing inside and I ran it with zilch for quite a while. Give yourself a baseline to start from.

 

[3-LockBox]

Dave, others, I have a question here. If he just puts the speaker
back in the hole as a cover is that other driver acting as a passive radiator? It's my understanding that a passive radiator is a speaker frame with no magnet structure.

It is, but not just any 6" driver is going to make for a decent PR, especially an old driver. The cone will be too thin, it will act more like an aperiodic port, and not a good one at that. But I wouldn't recommend a 6" radiator either. I would recommend an 8" PR, except I don't know the specs on the driver in question.

Hey rbclark,

I made a fullrange/PR combo and it turned out pretty good, but I used two 5.25" drivers in a .8 3^ft cab (22 liters), in a bipolar mounting, with a forward firing 8" PR (Dayton). If I could do it over again, I'd use a slightly smaller cab. Your's is a good size, I think, for that.

FWIW: some drivers do seem to need break-in (though many disagree, like Bob Brines). I don't know of any driver that will sound good in the senario you just described. The cabinet you're using right now, as is, is neither a bass reflex, or proper open baffle, and a driver would sound better laying in a pillow. You're hearing all kinds of anomilies at once, so don't listen to them that way any more.

If it were me I'd make the botton hole a tad bigger to accomodate an 8" PR, and I'd use the Dayton PR, or any reputable manufacturor PR, but don't think you're going to lop off the magnet of any old speaker and call it good. No. And do not use flat panel PR as they suck (there's a good explanation for why they suck, but for now...). You could maybe use a blown subwoofer, as they usually have nice thick surrounds and treated cones, but unless you can find two exactly the same, I'd just buy the PRs. Daytons can be purchased through Parts Express for a reasonable price.

Keep the tweeter hole in case you feel the need to add a super tweeter (many do), but cover it well. Cover all holes well and make sure the cab is sealed. A PR will not work properly in a leaky cab. Yes, there are pros and cons to using a PR, but sometimes its a matter of taste. I happen to like their sound compared to ports.