Is this really worth nerding out over?

[Gremson]

Originally Posted by jlepre

Let the NERDING OUT begin...

Was bound to happen eventually.

I had intended to do little things like line the back of the cab with foam. but resizing the ports and adding bracing like I've read a lot of you do is beyond my skill/desire for this cab.
Having the Speakers reconed isn't really ideal since my speakers don't match/aren't original.
Right now I'm pushing the cab with about 250 watts, but I'm looking to get something around 350 to 400 watts. I'm on the louder side of rock'n'roll, but not heavy. Most of the shows I play I line out to the PA, but I'd like to be capable of handling my own volume when needed.

I hope I've answered all the appropriate questions. I'll yank out a speaker when I get home from work tonight and get some measurements for you kind folks.
I've been researching and weighing my options between this, and buying a modern cab for a few weeks now. Every thread from here to the unofficial Acoustic Control forum get as far as "What are the internal dimensions?" and fizzles out. It would be nice to have a clear answer posted SOMEWHERE on the internet!

[jlepre]

http://www.avatarspeakers.com/scratch%20and%20dent.htm
Not sure if these are still available, but they might serve the purpose?

[BogeyBass]

No kappa, mud bucket No delta 15, fart bucket and no 3015lf mud bucket.

Legend CB158 or Delta Pro 15a
both same price delta pro has much more highend.
and 101 dB sensitivity much higher than the factorys around 97dB

the factory speakers are no where close to those drivers.
It will sound great. If a farty pair of mismatched speakers sounds good now, just wait till you plop in a matching pair of 101 dB monsters.

line the cabinet with batting and it will have unfound midrange clarity you have never heard

[Gremson]

Originally Posted by BogeyBass

No kappa, mud bucket No delta 15, fart bucket and no 3015lf mud bucket.

Legend CB158 or Delta Pro 15a
both same price delta pro has much more highend.
and 101 dB sensitivity much higher than the factorys around 97dB

the factory speakers are no where close to those drivers.
It will sound great. If a farty pair of mismatched speakers sounds good now, just wait till you plop in a matching pair of 101 dB monsters.

line the cabinet with batting and it will have unfound midrange clarity you have never heard

I like you.

[will33]

Agreed on the DeltaPro's for topend and just plain loud. The Legends are no slouch either, but "warmer/thicker". More that side of "classic tone" rather than the "bright/cutting" sort.

[Mr. Foxen]

Originally Posted by Gremson

Right now I'm pushing the cab with about 250 watts, but I'm looking to get something around 350 to 400 watts. I'm on the louder side of rock'n'roll, but not heavy. Most of the shows I play I line out to the PA, but I'd like to be capable of handling my own volume when needed.

If you are thinknig of being louder by getting more watts, getting more sensitive speakers is a better way to go, with decent speakers, you don't need much by way of power to get loud. Since you are doing speaker swapping anyway, might as well do that.

[BogeyBass]

Originally Posted by Gremson

Every thread from here to the unofficial Acoustic Control forum get as far as "What are the internal dimensions?" and fizzles out. It would be nice to have a clear answer posted SOMEWHERE on the internet!

36H x 30W x15D

minus .75 for 3/4 plywood on both sides is 1.5 for each dimension
and include a 1.5 setback for front baffle.

34.5 x 28.5 x 13.5 internal dimensions

7.6 cubic feet or 3.8 cubic feet per driver.

106 cab was manufactured from 72 to 76
was when Theile small practice was in full effect

so the port it most likely tuned to a generic 45hz

3.8 cubic feet at 45hz is just about perfect for almost any pro audio 15" speaker.

The 106 cabinet was advertised to be used with the 150B Bass head at the time and pairing the 2 together would complete the 156 bass system

[will33]

Yep, these are pretty much sized to "drop in" many different 15's and get a good result.

Agreed on needing more port area though. Can be as simple as cutting a little wood/pipe.

[BogeyBass]

Originally Posted by will33

Yep, these are pretty much sized to "drop in" many different 15's and get a good result.

Agreed on needing more port area though. Can be as simple as cutting a little wood/pipe.

Actually your right might have jumped the gun here.

Third gen ACC from 77 to 82 was when TS was used for the 406 wide/narrow and the 408 those have tuned slot ports for sure.

The 106 looks like to have generic holes drilled in the baffle so it is most likely a case of higher tuned older cabs, similar to the peavey cabinets or what not we have looked at here before.

I cant tell the size holes looks about 3.5 to 4" should be a easy fix just need to add port tubes to those holes. With 2 ports at 3.5 to 4" yes could be considered a little small for modern 500 to 800 watt systems. But the Delta Pro pair should be good for 300/330 watts and at that level i think port velocity should be ok. More important would need to figure out the port length he needs to add should be a easy fix

just need to measure those holes

[BogeyBass]

Kinda funny because i think those holes are gonna be about 4"

and so 2 4" ports would only have to have about 1.5 to 2" in length to get to 43/45hz the delta pro Fs is about 42/43 I think.

but if you calculate 2 x 4" ports at just .75 inch in length( depth of actual plywood)
with a volume of 7.5 cubic...minus bracing and drivers from 7.8

the tune is actually only a little higher at 49hz ...so it isnt gross amount of high tune....interesting.

[Gremson]

Them ports measure 4.5" in my cab.

And now we're definitely crossing into a dark, scary land where I am completely lost.

Ports! How do they work!?

[Arjank]

Originally Posted by Gremson

Them ports measure 4.5" in my cab.

And now we're definitely crossing into a dark, scary land where I am completely lost.

Ports! How do they work!?

If the cab is 7.6cubic feet(approx 225liters) and it has two 4.5" ports of 0.75" long, the tuning will be 47hz (if you use lining on the interior walls the tuning will drop approx 1hz)

Increase the port lenght to 1.5" the tuning will be 44hz.
Increase them to 3" the tuning will be 39hz.
These are some pratical values to work with.

Hope this helps.
(btw. I use a programm that also takes the position of the port (distance to left side of cab, distance to bottom... etc) into account, it's therefore a little more accurate then most programms)

[BogeyBass]

how ports work is a long winded explanation
and could be researched to further understand in detail

short answer, port frequency chosen is related to a specific alignment for a driver where its response matches the slope of electrical filter. At least early thiele/small research

realistically depending on driver the port frequency is usual slightly above or below the resonant frequency (Fs) of the driver.

Anyhoo if you use the delta pro 15's the Fs is 42hz and could simply tune a few hz above it around 43/45hz

the 4.5 inch cutouts you have now are about .75 inches deep pretty much a hole in the baffle. pretty inaccurate and would give a high tune around 52 to 54hz

Give you something more accurate you could just use a 4" flared tube for a tune around 43/45hz

which would simply need 2 4" ports 2inches in length, if people think the velocity is too high then use 2 6" ports at 6inches in length.

Parts express has a few flared ports which require about a 5inch cutout because they are flared and you would simply slightly enlarge the openings you have now and just screw em in.

2 i had in mind is

this generic adjustable which you would just cut to 2" which needs a 4 3/4 cutout

or the dayton system which is more expensive because you need the flared opening the coupling ring and the tube itself. and it needs a cutout of 5 13/16

I just chose those because the actually screw in not just glued and they would fit in what you have by slightly enlarging the current holes

they are flared so you have to compensate for that and I started you out a little longer at 2" and if you wanted to change tune you could shorten them to 1.5 inches

[Arjank]

Originally Posted by BogeyBass

the 4.5 inch cutouts you have now are about .75 inches deep pretty much a hole in the baffle. pretty inaccurate and would give a high tune around 52 to 54hz

The standard tuning of that cab is approx 47hz. See my post above.

[Arjank]

Here a simulation of the Delta 15A pro in a 3.8cu ft enclosure tuned to 47hz, fits like a glove (both impedance peaks are approx equal).
When I tune it to 42hz or 54hz, the impedance peaks are not distributed evenly.
If you choose the Delta 15A pro, you can leave the cabs tuning as it is.
In the other picture you can see the powerhandling, the driver will not be able to handle more then 200watts mechanically in the frequency-range around 75hz.

A driver that also would work is the Emi Delta 15LFA http://www.parts-express.com/pe/show...number=290-417 can handle slightly more power(only a tiny bit). The Delta 15A pro has a more extended top end, which is also something to think about.
This Selenium driver will also work though it needs a slightly lower tuning (41hz) http://www.parts-express.com/pe/show...number=264-464

Edit: I also simulated the CB158 vs Delta 15A pro(recommended by Bogeybass), both will have the same low-end response in that cab. The CB158 has slightly better powerhandling mechanically, it takes the 300watts without fartingout above the tuning frequency.

Now it's up to Gremson what he wants, Delta 15A pro or CB158.

Pros Delta 15A: more extended high-end and better sensitivity in the mids/highs
Pros CB158: can handle it's power rating mechanically(remark: in the low-end both drivers achieve approx the same max spl, the Delta 15A though can produce slightly more in the range above 100hz)

If I had to choose it would be the Delta 15A pro.