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Second opinion on speaker replacement

#41
Dont recone those square magnet pieces of junk.

The sensitivity of the legend CA154 (4ohm version) is lower than the 8ohm version. 96dB compared to 98dB
It has a smaller magnet and has a stamped steel frame not cast.
Royal piece of krap compared to the 8ohm version.
absolutely no reason to use it.

I have no idea why you would run a series load, it is poor practice.
if one driver blows you now have no load on the amplifier. And no sound. With a parallel load if one blows you still have sound, and still provide a load for the amplifier.

On a budget the 8ohm Legend, has a larger magnet, higher quality cast frame and more sensitivity. 5mm of xmax will give you a realistic 120 to 160 watts of power handling per speaker before 10% distortion

when looking at lower priced speakers they range from 79 to 99 dollars. most have 3 to 4mm Xmax. Most of them below 100hz will only do 40 to 80 watts before 10% distortion.

So within a budget build you can instantly tell that spending a extra 40 dollars per driver will give you much much more power handling.

A [Invalid or Expired Link Removed] 130 dollars a piece that is the bottom of the budget, running a pair will give you 250 to 300 watt cabinet. that is real numbers at 10% distortion. A manufacture would rate that as a 600watt cabinet......whatever makes you feel better.

Otherwise a step up in budget is going to be Neos.
Again the Eminence 3015 not the LF is at the bottom of the budget for Neos. power handling is not much different than a pair of legends. maybe and extra 70 watts so a pair will be about
340 to 400 watts instead of 250 to 300watts with ceramic.

The 3015LF can take alot more power, but it has lower sensitivity not higher. It is no different than the 4ohm legend sensitivity wise, about 96 db compared to the 3015 which is 98db.

Running a 3015LF as a fullrange speaker would be muddy poo poo.
they earned their fame by adding a 6inch midrange speaker. which makes up for the highs they dont have.
which include more cost of expensive 6" speakers and crossovers.

A pair of 96db speakers will give you a 99dB 2x15
A pair of 98db speakers will give you a 101dB 2x15

if you dont understand the difference between 2 to 3dB
it could mean almost another 100 to 150 watts to get the lower sensitivity cabinet to the same level. With a 3015LF to some is no big deal, because they can handle alot of power. But it takes more power to get them to the same place. using a 600 watt solid state no big deal.
200 to 300 watt tube amp could be a big deal. Depending on how loud your band is. For the most part the cost is more the issue.

The reason the tech is annoyed, is because every 2x15 built for the last 40 years is 3 to 4 cubic feet per driver. And almost every single one of them is tuned to 30 to 45 hz.
So if your talking about a JBL K140 or a EV15L or a Black Widow or a Legend CB158 they will all work in just about any 2x15 cabinet. The EV15L the JBL K-140 and the Legend CB158 are all within 5mm xmax drivers, so if your a old fart or new fart you are still looking at a bloody freakin 250 watt to 300 watt cabinet.

Long story short, use fabric batten to line the cabinet and load it with some eminence legends CA158. you will find all the jacks, corners and speakers at [Invalid or Expired Link Removed] mattress topper will lower the volume of the cabinet, just use polyester or cotton batting for blankets, it comes in a formed sheet, not loose stuffing for pillows or stuffed animals, cant find the link maybe thisjust needs to be a formed sheet not loose stuffing.
 
#42
Craig and Will I will be PM'ing you soon as I get to do some more work.

I actually live in Round Rock, but this week I am living in Austin so my cab's back home.

The win.. software I have never used, is it free and pretty easy to get the hang of? My dad is an electrical engineer and all around techy guy so he might figure it out.

I guess it looks like I'll be keeping this think but really want to keep this project under $500, as it's a peavey cab.

The reworking the ports could be done, but I'd need info.

As for the padding, I Think I used what the guy above is mentioned before. It's a like polyester sheet of batting, was like $9 for a big 10x10 square or something. How crazy do I go with putting that stuff in?
 
#43
You can get "quilt batting" at any fabric store around here. Layer it up anywhere between 1" and 2" thick. Some guys use spray glue 'cause staples might come out inside the cab. I staple it and uave never had one come out.. Wait wih that until after you're done with any modding/cutting on the cab or you'll just have hell trying to vacuum the sawdust out of it.

The cheaper mattress pad foam works nice too, I use that on most stuff. Just make sure it's an open cell foam, meaning you can easily blow through it, like an air filter. Some other types of bedding foam don't allow much if any air movement. That's the stuff that can "shrink" your box.

I'm in South Austin for what it's worth. That speaker works place is probably about 1/2 way from my place to round rock. I'm also working 11-12 hour days, but I'll help where I can.
 
#44
What exactly is your amp setup?

You mentioned something earlier about a stereo tube amp and maybe adding a guitar amp on the highs. That stuff's gonna matter as far as what impedance drivers you need, and how to wire the cab. Might need a separate input for each driver or somethin'.
 
#45
I have a Peavey windsor, my dad and myself are modding to be a bass friendly dirty tube amp. My plan is to also use a russian muff and mole bass boost pedal through a old peavey combo, without a head unit, so it's a black widow box with a space for cables.

Then thi2x15 will have a hybrid style amp with 300-500 watts for headroom to use bass and low mids, and a oc-3 into a q-tron into a Sansamp VT set to like black top.

The signal is brought to both sides by a GFS tuner pedal (it' cheap and bright) with a Y cable.

My basses are a bronco in standard to d standard, a P bass with flats in bead, and hopefully a telebass with flats in bead.
 
#46
I might be the dummy here, but back in the day, I just ordered a couple Carvin speakers and stuck 'em in there. It was an Earth cabinet, but the same design as yours. Check the specifications and whip out the soldering iron.
[Invalid or Expired Link Removed]
 
#47
Did a quick model with a delta 15 based on guessed dimensions: 3 cu feet, port 55cm wide,5cm high, and 10 deep. Is that about right?Tuning is about 55hz, specs show a big bump at 100 hz. Changing the port to lets say 30 wide, 5 high, 25 deep (centimeters) will get the tuning somewhere just above 35hz with acceptable chuffing. Padding will limit the 100hz bump.
 
#49
I don't know what you can achieve in the way of tuning within the box size and driver budget but 30hz response is a pipe dream for even the best of the best. Nobody has 30hz unless they have a PA with literally a truckful of subwoofers. What makes low B boomfy is lots of 60hz.

EQing my Trace 1518 I settle for B being "there". 30hz is completely nixed and 40Hz is also cut. D on up is properly grunty. It's a 15" oldschool BIG cab tuned to 40hz but it isn't loud at 40Hz. Shooting any lower makes it farty at high volume.
 
#50
Downunderwonder said:
I don't know what you can achieve in the way of tuning within the box size and driver budget but 30hz response is a pipe dream for even the best of the best. Nobody has 30hz unless they have a PA with literally a truckful of subwoofers. What makes low B boomfy is lots of 60hz.

EQing my Trace 1518 I settle for B being "there". 30hz is completely nixed and 40Hz is also cut. D on up is properly grunty. It's a 15" oldschool BIG cab tuned to 40hz but it isn't loud at 40Hz. Shooting any lower makes it farty at high volume.
Click to expand...

Tuning the port at somewhere near 35 hz is not for trying to achieve even response down to 30 hz. It makes for a nice even downslope from about 100 hz and a good xmax inbetween 30 and 40. It is exactly about the 30hz 'being there'. Also keep in mind the OP wants a bassy cab and spends a lot of time in the "doom" part of TB.

Oh, and Jimmy: lots of people like and expect that bump and in that cab it will always be there, but there is something like too much of a good thing.
 
#54
BogeyBass said:
I have no idea why you would run a series load, it is poor practice.
if one driver blows you now have no load on the amplifier. And no sound. With a parallel load if one blows you still have sound, and still provide a load for the amplifier.
Click to expand...

A series load has several advantages over a parallel load:

1. Assuming the speakers are identical model, and they are sharing a common chamber, the series configuration will have the same current flowing in both drivers so they will be forced to equally share the acoustic load.

2. If one driver does blow, and the remaining driver continues, the blown driver could act as a passive radiator and blow out the good driver. Essentially one driver stops, and the remaining driver is now operating in a too large cabinet with multiple tuning "vents". Having the good driver stop working will prevent it from blowing out from over excursion. A solid state amp does not need a load on it.

If the amplifier is a tube design, then of course it is good practice to keep a load on it and have one driver continue. That's where a parallel configuration makes sense. To prevent the above issue, the cabinet should be separated into 2 chambers with each chamber having it's own vent. That way, whatever happens to one driver does not effect the other driver.
 
#55
braud357 said:
No need to "overthink" this ! Parts Express sells a Peavey-brand 15" speaker, part #294-3122 for $67.19 each. I recently put one in an old 1-15" Peavey cabinet, and it sounds pretty damned good. It is a lot of speaker for the money!
Click to expand...
Agreed, those model well in many reflex cabs and do sound good. I've used the Pro 15 myself for low-budget projects. The problem is, at 2.5 mm Xmax it doesn't get all that loud before it gives up. For only $50 more one can get a pair of U.S. made drivers that will deliver 2x the piston stroke. But yeah, even Pro 15s will be an improvement over those evil square magnets from the '70s. It all comes down to how much money can be spent.
 
#56
Matthijs said:
The driver moves the least at the port tuning frequency. You use that to prevent farting. The cone movement rises enormous below the port tuning frequency, that's generaly where the danger zone is for farting.
Click to expand...
If it was as simple as that, cabs would be tuned to 30hz so we could pound on our B strings and never blow a woofer.

A higher tuning gets more of the harmonics of bass from the cab but you have to control the power input to the lows with EQ.
 
#57
2 Carvin PS15-8 drivers 69.00$a piece plus 15.00$shipping. 800watts @4ohms 36hrz- 3k of serious bstring thunder no augmentations needed on your cab. Shipped to your door 90days warranty! 10day try it or return it policy can't go wrong! You'll be350.00$ under your budget and will be well pleased with your purchase
 
#58
Tuning a box has almost nothing to do with note fundamental frequencies....you don't tune a speaker to a particular note. It's about shaping the lowend response curve, and making sure the box can "keep control" of the cone when you do send it low frequencies with power behind them.

One thing that took a while for me to wrap my head around, being a musician most of my life but just learning about the speaker end of things, was to mentally separate frequency and pitch. Though related, they are not the same thing at all.
 
#59
will33 said:
One thing that took a while for me to wrap my head around, being a musician most of my life but just learning about the speaker end of things, was to mentally separate frequency and pitch. Though related, they are not the same thing at all.
Click to expand...
exactly!

a string creates a whole bunch of frequencies, only one of which (and often not even the loudest one) happens to be the fundamental "pitch".
 
#60
Retroblaster said:
2 Carvin PS15-8 drivers 69.00$a piece plus 15.00$shipping. 800watts @4ohms 36hrz- 3k of serious bstring thunder no augmentations needed on your cab. Shipped to your door 90days warranty! 10day try it or return it policy can't go wrong! You'll be350.00$ under your budget and will be well pleased with your purchase
Click to expand...
Those used to be on my short list for budget drivers until I got the word from from two respected and trustworthy board heavies that what you actually receive may not be what you thought you bought.
 

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