Low-cost DIY practice/coffeehouse tweeterless 110 [long]

[George Mann]

Originally Posted by kraigo

Since I was down on the machine with WinISD on it and the driver model was handy, I took a look.

The positive is that the whizzer cone in the B102 would help a ton with the top end.

Another positive is that the B102 (not a BP102 - totally different creatures) seems to be not allergic to the small vented box.

In the box used in this project the B102 starts to drop off at 500 Hz, but pretty slowly. F3 is at 83 Hz, but that's not really where it starts dropping off rapidly. I'd say that by about 60 Hz you're really done.

If you look at cone excursion, the speaker is really not going to work out in this box, though. At least not without a highpass filter. My weak skills suggest second order at about 60 Hz. Even then you're limited to about 70 watts.

In short, I don't think the driver is TOTALLY unusable, but I wouldn't buy one for this cab.

KO

Well, I thought that this driver would serve as a good midrange, as your calculations show.

[George Mann]

Let's take a look at another cheap project. If it works out, it may even merit its own thread.

This is going to be a 210 in a dual-chamber sealed enclosure of .75 per chamber.

The specs for the 16-Ohm driver I had my eye on:

http://www.avatarspeakers.com/TF1020%20Specs.htm

The main concern is how much low-frequency extension this combo is going to yield. This is aimed at 4-string players.

[George Mann]

Sorry guys, but I cannot find enough info on this driver for WinISD. The link below does help a little, but the Small Signal Parameters are different.

http://celestion.com/product/107/tf1020/

[George Mann]

To condense the known parameters into one post:

10” 200W 16ohm

T5411

Specifications

Nominal diameter 10.08in

Cut-out diameter 9.02in

Overall depth 4.33in

Power rating (W) 200

Nominal impedance (Ω) 16

Sensitivity (dB) 97

Voice coil diameter (‘’) 2

Frequency range (Hz) 70-6000 (60-Hz according to the frequency response)

Re (Ω) 10.8

Mmt (g) 29.9

D (m) 0.21

Qts 0.47

Vas (L) 23.6

Qms 4.19

Bl (Tm) 17.23

Qes 0.53

Cms (mm/N) 0.14

Fs (Hz) 78

Rms (kg/s) 3.5

Xmax 2mm/0.08in

[fdeck]

Originally Posted by George Mann

Sorry guys, but I cannot find enough info on this driver for WinISD. The link below does help a little, but the Small Signal Parameters are different.

http://celestion.com/product/107/tf1020/

I've seen cases where different data sheets showed different parameters. Typically the changes are minor. Model it both ways and see if it makes a real difference.

[George Mann]

Originally Posted by fdeck

I've seen cases where different data sheets showed different parameters. Typically the changes are minor. Model it both ways and see if it makes a real difference.

No good. It won't accept the data!

[fdeck]

Originally Posted by George Mann

No good. It won't accept the data!

Leave some of it out. Winisd only needs the basic parameters, and computes the rest. Those are --

Fs
Re
Le
Qes
Qms
Sd
Xmax
Pe

I think that's right, it's been a long time, since I wrote my own modeling program.

[kraigo]

I'm not an expert with WniISD, but I've played with it a fair amount. IME, the procedure outlined in the help for WinISD, which parameters to add in which order, which parameters to let WinISD calculate, has generally resulted in a good driver model.

YMMV.

KO

Added: also bear in mind that WinISD driver files are just text files with a different extension. When you get a valid driver model, open the .wdr file with NotePad, copy all of the contents and paste it into a post here. You may get more help with your project that way.

[George Mann]

Edit: I deleted the entire post because none of the calculators work with my set inputs.

[George Mann]

According to Eminence, the BP102 will work in the original project box with a modified vent. Any ideas?

Since it has a much smoother response to 2Khz, it will make a better 2-way.

[kraigo]

I've got a BP102-4 based 1x10, so I've got a bit of interest and experience with it. Most things you'll read will tell you that the high end really cuts off around 500 Hz - 800 Hz and that the BP102 likes a larger box. Both are prices you pay for the relatively large amounts of low end the BP102 puts out.

My own BP102 cab has a fourth order crossover at either 700 or 800 Hz. Sundogue built a couple of BP102 cabs and posted in response to my query that 800 Hz sounded best to him. My cab has a fabric dome mid that takes upper end response into the 5 - 7 KHz range, which is fine for bass guitar.

Sundogue's uses an Eminence Alpha 6 mid, I think. He uses a Carvin head with bi-amping to power them. It's quite a rig. I've played with designs using the BP-102 and an Alpha 6A. You have to pad back the Alpha 6A quite a bit to get the response to be more even, but I think it would be a good sounding rig. One design I had done had a 1.75 ft^3 box with a 40 Hz tuning. F3 models to 42 Hz, it can take up to around 82 watts before distortion and would put out around 110 dB. The driver excursion is equal to the resonance hump's excursion when you hit 33 Hz, meaning that you can pound on a B string all day long and as long as you aren't distorting at the resonance hump (60 Hz), low end excursion is pretty damned safe. The cab would be great for five string.

The S2010 box modeled with a 58 Hz tuning (blocking the port a bit as suggested by Duke early on in this thread), can take 100 watts before distortion putting out 114 dB. F3 is around 66 Hz. Cone excursion is an issue starting at around 48 Hz and rising rapidly as you go down from there, assuming you don't put in a high pass filter. Given the reality of how much fundamental is in a typical bass guitar signal, this may not be necessary. This cab would probably be fine for five string, but a little care is a good idea.

I personally would not try to use a BP102 in the box used in this thread because the .9 ft^3 box is too small to really let the BP102 blossom in the low end, which is its forte and because you want a mid to pickup the signal at a fairly low frequency and there isn't room in the baffle of this box for it.

As time permits this long weekend I hope to play with models of the Eminence 3010MB. The 3010LF appears to be a bit of a let down, having read about it yesterday and looking at the Eminence recommended cabinets. You'd be about as well off to use the BP102, which I think is a great speaker.

The 3010MB may be closer to the S2010 used in this thread, I haven't had a chance to look you. But this is an intellectual exercise. I have two S2010's waiting for me to finish their boxes and I'm more inclined to use my time toward that end this weekend than researching the 3010MB. One brief comment I've seen suggested that the 3010MB is similar to the S2010 but beefier, but I haven't verified.

I'm sorry if I'm being negative. I have looked through a lot of Eminence's 10 drivers over the last couple of years and I came away with the impression that the S2010 and the BP102 are the two gems of their products for bass guitar use. Nothing I've seen since has really changed my mind. The Beta 10CX Duke mentioned a few pages back is not bad and if I wanted to make a small co-axial cab would probably be a fun project. I like the way the S2010 models better than the Beta 10CX, though.

KO

[George Mann]

Thanks for the reply. I have been rethinking the use of the Celestion driver. It appears to work fine in a 1.5cu in enclosure, and has good midrange to boot.

A calculator I downloaded indicates that the box below will work with just a 4-inch hole cut out of it.

http://www.ebay.com/itm/SEALED-10-CA...item35c23ef9e7

[George Mann]

I have another cabinet here:

http://www.ebay.com/itm/NEW-Q-POWER-...item5ae8f2890b

Calculations indicate that it may work fine with the Celestion if I restrict the port width to 8-inchs.

[kraigo]

Back on topic...

I've had the Vifa tweeter and the crossover (highpass filter for the tweeter, I'm pretty sure) components for some time. Some of the parts for one of the cabs got used for the combo amp that I popped an S2010 into. I also have a pair of home audio speakers I need to put together, so yet another Parts Express order is in the making.

I never looked into the ripple filter that Duke had designed all that closely. I am largely just playing to gain a little experience with crossovers and filters, but I'd like to see if I can make my two cabs workable as both bass cabs and small PA cabs. My medium sized PA is a pain to get out of the basement and often I just need something that will project over an acoustic band in a noisy room.

Duke's initial post on the filter is here: Low-cost DIY practice/coffeehouse tweeterless 110 [long]

Duke's tweeter mod is here: Low-cost DIY practice/coffeehouse tweeterless 110 [long]

I recall that somewhere in this thread someone posted links to the tweeter components. In the interests of cost effectiveness, I'm planning on addressing the 1.5KHz notch filter but not the 2.5KHz notch filter because Duke suggested that the 1.5 KHz filter would have a more noticeable affect.

So, my plans are to block out some of the port to lower the Fb, mount the tweeter in the port, mount a cup handle in the port and put the crossover and notch filter in the port as well, all mounted so I can take things apart and get at them should the need arise. The filter, crossover and tweeter will be switchable so I can just run the woofers full range for bass if I want to.

But first, I just want to get the basic box working. Still I need to place an order to PE for the home audio speakers, so I've spent a bit of time finding the 1.5 KHz filter's components on the PE site and pricing it out to see if I really want to follow through. The point of this post is to share the research.

The required components for me are the caps, the coil, the resistors and the switch. Optional are the cup (I should be able to use the cup the input jack is housed in), the gasket for the cup (I'd use aquarium sealant if I need to use the cup) and the rubber boot for the switch (if the MDF cab gets wet, it's pretty much toast anyway, right?).

Here is the list of components, their cost and the links to them.

Qty Description Unit Price Line Total Link
1 50uF Cap 13.1 13.1 http://www.parts-express.com/pe/show...number=027-443
1 5.1uF Cap 2.54 2.54 http://www.parts-express.com/pe/show...number=027-423
1 Jantzen .2 mH Inductor 3.41 3.41 http://www.parts-express.com/pe/show...number=255-024
3 20 ohm 20 watt resistor 0.79 2.37 http://www.parts-express.com/pe/show...tnumber=017-20
1 SPST Toggle Switch 1.69 1.69 http://www.parts-express.com/pe/show...number=060-370
1 Cup to mount switch 4.79 4.79 http://www.parts-express.com/pe/show...number=262-324
1 RubberBoot for switch 1.88 1.88 http://www.parts-express.com/pe/show...number=060-378
1 Gasket for cup 0.53 0.53 http://www.parts-express.com/pe/show...number=262-049
Necessary parts total 23.11
w/Optional parts total 30.31

$23.11 for the filter, per cab. That's for a partial filter, not addressing the 2.5 KHz hump. Pricey for a small cab (but it would move me into free shipping with PE )

KO

P.S. Ordered, just in the interest of learning something about crossovers and how they sound and in the hopes that $41 ($46 - $5 for ordering too much crap from PE these last couple of months) will give these cabs some serious utility for me.

[Woodstockz]

Originally Posted by kraigo

I've got a BP102-4 based 1x10, so I've got a bit of interest and experience with it. Most things you'll read will tell you that the high end really cuts off around 500 Hz - 800 Hz and that the BP102 likes a larger box. Both are prices you pay for the relatively large amounts of low end the BP102 puts out.

...

KO

Kraigo, What size is your BP102 Box?

I had a defective BP-102 that I had to send back to Parts Express. It was dark and scratchy sounding. I'm waiting for the replacement.

[kraigo]

I think dark is pretty normal. They're optimized for low end. Scratchy is not.

My cab wasn't designed around a BP-102. It was an old Len Moskowitz cab from the early 90's where a friend and I got stupid with it and blew out the original woofer. The original woofer was out of production, so the cab sat for years before I found the BP102-4 (four ohm) that would pretty much drop right in.

My cab is around 1.6 ft^3.

Glancing through various WinISD projects I have for the BP102, 2 ft^3 (roughly a 16" cube) tuned to 40 Hz gives you an F3 of 43 Hz but limits you to about 65 watts before distortion. SPL at 65 watts models at 110 dB.

On the other end of the spectrum, a 1.25 ft^3 box (roughly a 13" cube) tuned to 42 Hz gives you an F3 of 53 Hz, which is really fairly respectable for a small box. It would take about 90 watts before distortion. SPL at 90 watts models at 113 dB.

My 1.6 ft^3 box will probably get retuned at some point, but either way it's tuned at around 41 Hz and gives an F3 of 47 Hz. For some reason WinISD is telling me it can take 400 watts before distortion, which is absolutely wrong. The retuning would give me some better cone excursion results and more port area, so less chuffing. I like this cab a lot. Both Bill FM and Greenboy have poo-poo'd the article for various reasons. It's available here: http://www.core-sound.com/bottom-article.html.

Lastly, a 1.75 ft^3 box (roughly 14.5" cube) tuned to 40 Hz gives an F3 of 42 Hz, takes about 83 watts before distortion and again gives about 110 dB before distortion.

At the moment I'm thinking that a net volume of 1.5 - 1.6 ft^3 might be a sweet spot for the BP102. It gives good low end and is safe for a B string and can handle a bit of power.

Good luck!

KO

[Woodstockz]

Originally Posted by kraigo

I think dark is pretty normal. They're optimized for low end. Scratchy is not.

...snip...

At the moment I'm thinking that a net volume of 1.5 - 1.6 ft^3 might be a sweet spot for the BP102. It gives good low end and is safe for a B string and can handle a bit of power.

Good luck!

KO

Thanks for the data points.

I just got my replacement BP-102 today from Parts Express. My test box is right about at 1.5 ft^3.

I'm using an Ampeg PF-350 for a head. I really like this combination, it sounds really sweet. Time to go play it more, er, I mean test it more.

[MX21]

I just noticed that the S2010 prices seem to be coming down. $99 at both parts-express and Amazon.

[Woodstockz]

Originally Posted by MX21

I just noticed that the S2010 prices seem to be coming down. $99 at both parts-express and Amazon.

That's good news. I also noticed a recent price reduction in KappaLites. Hopefully, this trend will continue.

I am still loving the BP-102. I bought it on a recommendation, but I never would have bought it just looking at the specs.

P-bass with flats, PF-350 and BP-102 = Classic old school tone.

[kraigo]

Do you have anything picking up the top end? I've never heard a BP-102 without anything carrying the top. I would think that it'd be too dark. I like the S2010 I have in my little Traynor 20 watt tube combo quite a lot. But that goes to around 4 KHz. I'd describe that as a nice old school tone.

Most of the things I've read suggest that by about 1 KHz (two less octaves of top end) the BP-102 is done.

KO

Originally Posted by Woodstockz

That's good news. I also noticed a recent price reduction in KappaLites. Hopefully, this trend will continue.

I am still loving the BP-102. I bought it on a recommendation, but I never would have bought it just looking at the specs.

P-bass with flats, PF-350 and BP-102 = Classic old school tone.