FR Speaker Build--Ignorant Newbie Questions

[inputs]

Hello everyone:
This is my first post to the forum. I've been lurking for a couple weeks now, and I'm amazed by the amount of information presented here. In fact, I'm rather overloaded by options and opinions. So, I wanted to post and ask for some advice.
I listen to all types of music. Between me and my SO, the speakers I hope to build will be used for jazz, classical, and rock, but almost always at modest SPL levels. My collection of high quality stereo equipment is... well, none. I will most likely connect my shiny new (as-yet-undetermined) speakers to a boring pioneer receiver (VSX-2000), or possibly a Kenwood KA-3500 (once it's cleaned up and operational). I do, however, intend to build a moderately powered SS amp in the near future, and I want to plan accordingly. My listening room is about 12' x 15', with hardwood floors, and I can't depend on corner loading because of SO restrictions. (Loading against a wall should always be possible).
I have a sufficient variety of tools and woodworking experience that "ease of build" is much less important than the sound of the speaker.
Cost is an important issue, as the more expensive this project becomes, the longer I'll have to wait to build it.
One other complicating wrinkle: I have toddler who is obsessed with buttons. So, anything I build must be sufficiently immovable to prevent her from knocking it over, have rounded edges (where possible) to alleviate injury when she inevitably crashes into it, and must conceal anything that looks like a button (hence, speaker grills are required).

Based on what I've garnered, I think the following designs have promise for me:

CHR70 halfTower design (microTower variant)
some monolith variant (Mileva w/ FR125?)
B20 half-chang w/ a tweeter
miniOnken (FR125, naturally)

I would appreciate any input, recommendations, or words of warning you may have to offer.

Thanks,
_Ben

 

[edjosh23]

Welcome!

How are your woodworking skills?
You mentioned speakers near the back wall... what about corners?
I'm not sure how the Mileva will work with the FR125, but you may want to get your hands on a FE127 while you still can (don't tell others I'm suggesting you take one from the lot that is left).

Good Luck,

Josh

 

[planet10]

CHR70 halfTower design (microTower variant)
some monolith variant (Mileva w/ FR125?)
B20 half-chang w/ a tweeter
miniOnken (FR125, naturally)

Ben,

Having something to do with all of those, a few comments...

1/ Also consider the EL70 version.
2/ Mileva needs FE127 (and those are getting very scarce), I will be doing an EL70 version. Maybe a CHR version later.
3/ halfChang is good, and you'll be hard pressed to put togther a project for less... the B20s don't have the finese of any of the other mentioned drivers, but have more bass (althou the EL70 can go almost as low), and would be capable of playing louder (which you don't seem to need)
4/ althou the miniOnken was the box that spawned many very good miniOnken variations, it needs its ports damped to keep it from hitting its stops. The 4.5 litre aperiodic box is better (IMO). There is a version of this box for the EL70 (what i'm listening to right now) which i feel is the best of all mentioned in this post, You would need to engineer stands that keep them bolted down.

dave

 

[inputs]

@edjosh23 I have adequate woodworking skills. Especially in terms of actual construction. My finishing techniques could use further development--or I might just paint my speakers a nice solid color. As for corners: as long as the SO insists on the present furniture configuration, I don't have access one of the corners in the listening room. Another is blocked by the front door, and the third opens into another room. I might be able to corner load a single speaker--but that's about it.

@planet10
1/ Would you provide some insight into the differences between the EL70 and CHR70? I don't see a datasheet on the CSS site, but I assume the T/S characteristics are similar considering the minor changes to the halfTower depending on driver selection.

2/ I'll provisionally rule out the Mileva until the EL70 version is done. I really like the tombstone look of these speakers, so I'm looking forward to a version that uses a readily available and inexpensive driver.

3/ Would the B20 build be better suited to occasional employment in a home theater system? (than say, a EL70 halfTower).

4/ Are you referring to the plan which specifies the FR125 speaker? I like the aesthetic of that box, and may build a set in parallel with my main project for use as computer speakers.

One other question about the halfTower: would it be a good idea to utilize some type of BSC? Where can I go to get information about how to configure the circuit?


Thanks for the input!

_ben

 

[hm]

Hello inputs,
"I would appreciate any input, recommendations"

for your room size i would prefer
my Kornett double horn:
down 34 Hz, soundstage, small, cheap.

Or a few others you find on my HP

 

[Glowbug]

Something like a BIB would be tall, but you could build out the base to be much wider to give it stability. The drivers would be high enough up the cabinet to keep them out of reach

 

[planet10]

1/ Would you provide some insight into the differences between the EL70 and CHR70? I don't see a datasheet on the CSS site, but I assume the T/S characteristics are similar considering the minor changes to the halfTower depending on driver selection.

Althou they use the same basket, spec is not the same. The EL70 datasheet should be on the CSS site, i have it here. Dimensions.

2/ I'll provisionally rule out the Mileva until the EL70 version is done. I really like the tombstone look of these speakers, so I'm looking forward to a version that uses a readily available and inexpensive driver.

The recent surprise that Madisound wasn't able to stockpile these has rocketed this design way up in the queue. With the Alpair 12 miliOnkens now done (at least 1st pass), this may be next up.

3/ Would the B20 build be better suited to occasional employment in a home theater system? (than say, a EL70 halfTower).

My system serves dual purpose... personally i'd choose EL70. I've had 4 B20 in their box for over a year, just can't get excited about tarting them up (i did do one pair for a client).

4/ Are you referring to the plan which specifies the FR125 speaker? I like the aesthetic of that box, and may build a set in parallel with my main project for use as computer speakers.

Yes. The Fonken followed in its footpath and a whole range smaller, larger, and the same. The EL70 Mar-Kel70 is the same size.

One other question about the halfTower: would it be a good idea to utilize some type of BSC? Where can I go to get information about how to configure the circuit?

I always feel BSC circuits are a bandaid, they can never completely sort the problem. A line level crcuits is better, acoustic solutions even better (why there is a halfTower and a tower, and not a tower and a doubleTower). If you can place them near a wall, any BSC will be minimal. Martin King's paper of Rod Elliot's article are a good start for circuits. A good general purpose starting place.

dave

 

[inputs]

@hm the cornet looks really interesting. I've saved a link to the design page. It looks like the two horns are different lengths, so I assume that you've tuned the back loaded and front loaded horns differently. What's the reason for this?

@glowbug I've looked at the BIB plans/spreadsheet/threads and I do like the line. I looked very closely at building an inverted BIB (iBIBk) since I can't corner load the speaker, but I think for the sake of domestic peace I'm going to start with something smaller.

@planet10 Thanks again. I'll look over papers you linked me to. Since these will usually be against a wall, I'm optomistic about avoiding the added complexity and cost of a BSC. I'd be very interested in a Mileva for the EL70. I'll keep an eye out on the forum for the plans to be posted. In the mean time, I'm leaning toward the EL70 halfTower.

I really appreciate the help.

 

[chrisb]

@hm the cornet looks really interesting. I've saved a link to the design page. It looks like the two horns are different lengths, so I assume that you've tuned the back loaded and front loaded horns differently. What's the reason for this?

@glowbug I've looked at the BIB plans/spreadsheet/threads and I do like the line. I looked very closely at building an inverted BIB (iBIBk) since I can't corner load the speaker, but I think for the sake of domestic peace I'm going to start with something smaller.

@planet10 Thanks again. I'll look over papers you linked me to. Since these will usually be against a wall, I'm optomistic about avoiding the added complexity and cost of a BSC. I'd be very interested in a Mileva for the EL70. I'll keep an eye out on the forum for the plans to be posted. In the mean time, I'm leaning toward the EL70 halfTower.

I really appreciate the help.

I'm almost as familiar as Dave with the combinations of enclosure/drivers discussed, and have some observations to pass along:

Mileva:
with an appropriate driver, and if you have the wall space available, I think it's safe to say the Mileva wouldn't require BSC of any sort. It's width/depth ratio can cause some placement issues in regards to toe-in for imaging sweet-spot.



Micro-tower:

If budget permits, the dual driver "castle" version would be my recommendation - I'm running a pair upstairs with a cheap Sony 23W or so receiver. The up-firing second driver adds a lot to ambience/dimensionality, and their small footprint makes placement fairly problem free (unless there is a low overhanging boundary shelf/counter etc.) - certainly more so than the bipole version.

They can definitely produce bass if corner mounted, but with the potential of some boominess, as well as exaggerated separation if more than about 8 ft apart. In my case, they are a couple of feet either side of a couch, and angled towards the main listening area, and sitting on 12" squares of granite (countertop sink cutouts).


The current availability status of the Fostex FE127E is a bit of a bummer for those of use who've found it a "go to" driver for the past 5 or 6 years, but we'll adapt - maybe we'll even find our own new "it" driver.

The late (and perhaps not all that lamented) Hemp Acoustics' FR4.5 was an interesting little driver - definitely a different flavor, but still fun.

 

[inputs]

@chrisb but if i make the castle version, where will i set my beer?

I would like to do the castle version, but since this is my first build, I'm inclined to make it more inexpensive where possible.

If I were to buy a second set of EL70's I'd be very tempted to slap together a set of the aperiodic enclosures Dave suggested earlier.

_ben