Unusual Qts Value?

[shlshh]

I'm brand new to speaker design and am trying to make a full-range pair on the cheap (investment of <$100 hopefully!).

The extent of my design plan is to choose full-range drivers and plan an enclosure around them based on the Qts and equivalent volume parameters (nothing too ambitious for the first project).

The two drivers which I was looking at are
The Madisound Speaker Store
HiWave BMR12 Compact 2" Full-Range Square Speaker 12W 8 Ohm 299-208

On the first driver, I as very surprised at the Qts value on the spec sheet -- 1.45! It seemed quite high, and gave me some funky results when for box volume. What gives? I thought Qts typically were less than 1?

As a preemptive reply to any suggestions of moving up to higher-end drivers... I realize that my objective of using small and cheap full-range drivers will inevitably prevent the end product from having high quality sound. As my first project I'm not too concerned with this, and am thinking of this pair as a low-entry learning opportunity. The projects I've seen on this site are truly inspirational and I hope to someday reach that quality. Thanks in advance for any help!

 

[planet10]

For less than $100 you can afford more expensive drivers.... both of these are really mid-tweeters

dave

 

[Toberius]

Hehe, the work time is more expensive what 10 pc each !!

 

[Inductor]

This is a good (world classic) starter. Post your project pics (for our enjoyment...)
Fostex FF85WK 3" Full Range The Madisound Speaker Store
8?????????Fostex FF85WK????California Girls?(Papa Doo Run Run) - YouTube
??????FF85WK?????DR-07II?????????? - YouTube
FF85WK - YouTube
http://spc.jpn.org/zumen/MS-802T-mk4_zumen.jpg
http://spc.jpn.org/zumen/max85_zumen.jpg

The projects I've seen on this site are truly inspirational and I hope to someday reach that quality.

 

[planet10]

T
Fostex FF85WK 3" Full Range

One of my favorites. Will produce better, deeper bass than eother of the 2 originally posted but still bass shy.

My personal uFonkenSET with FF85wKeN

dave

 

[DrBoar]

A 2" will have no real bass what so ever so having a high Q giving at a peak in midbass lower midrange improves the thin bright balance it otherwise would have. The highly respected BBC monitor LS3/5A had no bass below 80 Hz but a peak in the octave above that to give the impression of bass, so in some setting it is a valid design option to use even if it is not the purist approach.

 

[IG81]

FF85WK is a cool little driver. Personally, I prefer Tang Band W4-1320SIF, which is priced a tad lower to boot. Either driver should be able to have a pair of simple vented enclosures fit in a single 0.5" BB-ply handy-panel from Home Despot. Add some decent connectors and wire and you're not over the budget by very much, assuming you already have all required tools, workbench and glue at home...

IG

 

[Godzilla]

>>> My personal uFonkenSET with FF85wKeN

Gorgeous!

Both the Fostex and TB suggested are great. Any 3" TB in a sealed box seems to work really well. You can add a subwoofer later to improve the bass.

 

[planet10]

Gorgeous!

An example of the fine woodwork Bernie does. These are solid Yew.

dave

 

[Inductor]

silly-little-buggers drivers

One of my favorites. Will produce better, deeper bass than eother of the 2 originally posted but still bass shy.

My personal uFonkenSET with FF85wKeN

Another driver to consider with F3 ~40Hz, Aurasound NS3-193-8A 3" Fullrange Price: $23.00 (each) Madisound. (Mid. pic)
That's all for today (dinner).

More references:
Dayton Audio ND91-4 3-1/2" Aluminum Cone Full-Range Driver 4 290-224
http://www.daytonaudio.com/media/resources/290-224-dayton-audio-nd91-4-specifications-8418.pdf
Tang Band W3-1878 3" Full Range Driver 264-902
http://www.tb-speaker.com/detail/1230_04/w3-1878.htm
http://www.madisound.com/store/manuals/aurasound/ns3-193-4a.pdf

DAYTON RS100S-8 and 4. Price: $28.85. Iinteresting silly-little-bugger driver (pic right).
Dayton Audio RS100-4 4" Reference Full-Range Driver 4 Ohm 295-378
http://www.daytonaudio.com/media/resources/295-378-dayton-audio-rs100-4-specifications-46166.pdf
http://www.daytonaudio.com/media/resources/295-352-dayton-audio-rs100-8-specifications-47076.pdf

This one is interesting, might work as a good mid/tweeter combo for top frequencies in a 2-Way (woofer+midrange).
Eton Symphony 3" Midrange 3-400/A8/25 MG, Matched Pair Price: $245.95 (each)???? (pic left). The Madisound Speaker Store
Fountek FR88EX 3" Neodymium Full Range Driver 296-719
The Madisound Speaker Store

 

[Godzilla]

I've owned Eton drivers and just don't get it. I sold them because they were too difficult for me to figure out how to make them sound good. I'm told I do not have the skills and I am fine with that explanation. The pic on the left looks like a rather ordinary driver (just like the ones I owned and could not work with). They sounded like crap to me, kept me up at night thinking thru crossover components and were totally unenjoyable. I think the baskets were made of plastic too. I don't care what material they use for the cone, they are overpriced.

 

[EdKennedy]

If you can afford a little more cost, I recommend MarkAudio CHR-70 in the box of your choice. The speakers with shipping will be about $82. A sheet of MDF will run about $36. Terminals, Glue, and Paint will cost about another $20.
I know the experts here like cabinets in Baltic Birch, but I think a great driver in a MDF cabinet will sound much better than a lesser speaker in an expensive box.

 

[shlshh]

Forget the budget, I'll just go straight for the Etons!

But seriously, thanks for all the feedback. I wasn't expecting nearly so much help! Those TB W3-1878s are gorgeous, I'm bookmarking them.

I'm liking the approach of making a decent pair of which might lack bass and adding a sub later when I save up a bit more. My plan was to make sealed enclosures out of MDF.

Now I'm sitting here with about 15 tabs open looking at different drivers. Before I pull the trigger on any, I want to try to understand what makes some of these more expensive than others. I've got an example of exactly what is confusing me.

Fostex FF85WK
vs.
Fountek Fe85

What I'm seeing is two drivers with similar resonance frequency (115Hz vs 125 Hz), similar Qts value (0.55 vs. 0.52) and similar Vas values (1.036L vs. 0.85L... maybe not too similar).

These are the main parameters I've been using for design. I guess I'm not taking into account enough parameters.

 

[planet10]

Fostex FF85WK
Fountek Fe85

I've not heard the FE85, but it is the real cheap brother of the FR88ex of which i bought 24 of when the FF85k was discountinued. It wasn't as good but had potential and it filled a void. Before i sold any the FF85wk came out. It was definistly better (than both the FF85k or the FR88ex). So it is pretty easy to extrapolate that the FF85wk kills the FE85. Doesn't make the FE85 a bad driver, especially when you consider it is ~1/3 the price.

All the parameters do is give you an idea of what kind of bass performance you can get.

dave

 

[Godzilla]

I always wanted to try the TB 1053.
Tang Band W3-1053SC 3" Full Range Driver 264-880

Visaton BG17-8 6.5" Full-Range Speaker with Whizzer Cone 292-546

Tang Band W5-1611SAF 5" Full Range Speaker 264-918

Dayton Audio PA130-8 5" Full Range PA Driver 295-010

I'd look at these and anything from Fostex.

 

[Xaborus]

Forget the budget, I'll just go straight for the Etons!

But seriously, thanks for all the feedback. I wasn't expecting nearly so much help! Those TB W3-1878s are gorgeous, I'm bookmarking them.

I'm liking the approach of making a decent pair of which might lack bass and adding a sub later when I save up a bit more. My plan was to make sealed enclosures out of MDF.

Now I'm sitting here with about 15 tabs open looking at different drivers. Before I pull the trigger on any, I want to try to understand what makes some of these more expensive than others. I've got an example of exactly what is confusing me.

Fostex FF85WK
vs.
Fountek Fe85

What I'm seeing is two drivers with similar resonance frequency (115Hz vs 125 Hz), similar Qts value (0.55 vs. 0.52) and similar Vas values (1.036L vs. 0.85L... maybe not too similar).

These are the main parameters I've been using for design. I guess I'm not taking into account enough parameters.

Prices of drivers usually don't mean much, other than a nice placebo effect and usually higher priced drivers usually have better quality control. Some very expensive drivers are terrible, while some moderately priced drivers are very good.

The Japanese have a cult following of the Fostex FE103En.

 

[Inductor]

Visaton BG17

Besides it's use as a "mid-range in a 3-way combination", link for MB 156/3, it's only gonna work as OB (or some kind of Onken).
Not really a "full-range" speaker driver if you don't know how to use it, and place it in a box.

 

[Hanatsu]

The Eton 3-400 is a great driver. Replaced my Fountek FR88EX with those. Really good HD performance in the low end of their usable range. Here's FR/HD/Impedance plots;

Imp. Plot was taken with the drivers right out of the box. After some burn-in Fs/Qts are likely to go down a bit...


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