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My starter rig - Mostly DIY.

S

Stromrider

Feb 16, 2008
162
0
CT, USA
#1
Well, I've been playing for a year or so now, and finally decided i need to upgrade from my clunker combo. I'm using an Ampeg G100 (yeah, the regular guitar amp... :rollno: ) which i got for free with a blown driver and the amp needed some help to get working well again. I've been using it with a 10" that came out of some Fisher speakers; cleaned up the amp board and replaced a few leaking caps. Yeah, it sounds like dirt... but it works and it got me started. I play a Peavey Milestone III which i got for an awesome price (free) and i have a cheapo Squier P bass but i play the Peavey more often. Just looking for a good sound...

So, i'm good with electronics, and loudspeaker design/construction so i'm planning on building a cabinet and a preamp. The preamp will be basic, just pre vol - three band tone controls - master vol. Its an opamp based design. I'll probably add a compressor, maybe a used dbx or a behringer.

The cabinet will consist of a 15" Eminence 3015LF which seems to be the most used for diy cabs around here. Planning on 4.5-5ft^3 ported, tuned to 45hz or thereabouts. Next inline will be an Eminence Beta 8" in its own selaed compartment, and i haven't decided if i'm going to add a horn or not. I'll leave space on the front baffle to add one if i want.

I am going to use an active crossover, the Behringer CX2310. I could design a passive xo easily enough, but active gives me much more control over the sound of the cab. So i'll need up to three channels of power. I have a Hafler P125 (200w into 8r bridged) or a Hafler P230 (360w bridged) to run the 3015LF, and i'm going to build two LM3886 based chipamps (50w) into the preamp case for the mid and tweeter (if i use one). Signal chain would be guitar > diy preamp > compressor > active xo > power amps > two or three way cab.

Does anyone see any potential holes for me to fall in, or anything else i should consider adding? Thanks!
 
#6
synaesthesia said:
You might to try this chain:

bass - preamp - crossover - compressor channel for hi, compressor chanel for low - into power amps - feeding your cabs.
Click to expand...

I'll try that if i end up with a two channel compressor - i wouldn't have thought of that. Thanks!

amos said:
In my opinion, an all diy setup is as sick as it gets. If it thumps well thats an added bonus. Being poor (like me) is a great incentive to learn from some one and then continue to diy
Click to expand...

From what I've seen, some of the most renowned cabinets use Eminence, Selenium, Peavey, etc... drivers; most of which are available to us pretty cheaply compared to the cost of the finished cab with a name on it. Pretty good incentive right there to diy...

Ask questions - Answers will follow. ;)
 
#7
Minor change in plans... I'm thinking about using this 18" instead of the 15" Eminence.

[Invalid or Expired Link Removed]

Its cheaper (always a bonus), delivers lower frequency response in a smaller box and has plenty of xmax for the power i plan on throwing at it. Only drag is its 4 ohm, so i can't bridge my Hafler amp to power it. One channel on my P230 will give me 180w into 4r so that'll be fine until i get another, bigger amp. And this way i won't need to build the chipamp for the midrange as I can just use the leftover channel on the Hafler. Which also means i don't have to devote a big case to the preamp...

I've used Dayton Loudspeaker drivers in the past and have always been happy with them. I use some of the Reference series in my main audio system.

The 18" gets down to a 40hz F3 with a slight bump in a 3.8ft^3 sealed cabinet, compared to the vented 4.5ft^3/45hz F3 for the Eminence 3015LF.

With the 70$ i'm saving on the woofer, how about I step up to a 10" mid? Or should i just stick with the 8"?
 
#8
Stromrider said:
Minor change in plans... I'm thinking about using this 18" instead of the 15" Eminence.

[Invalid or Expired Link Removed]

Its cheaper (always a bonus), delivers lower frequency response in a smaller box and has plenty of xmax for the power i plan on throwing at it. Only drag is its 4 ohm, so i can't bridge my Hafler amp to power it. One channel on my P230 will give me 180w into 4r so that'll be fine until i get another, bigger amp. And this way i won't need to build the chipamp for the midrange as I can just use the leftover channel on the Hafler. Which also means i don't have to devote a big case to the preamp...

I've used Dayton Loudspeaker drivers in the past and have always been happy with them. I use some of the Reference series in my main audio system.

The 18" gets down to a 40hz F3 with a slight bump in a 3.8ft^3 sealed cabinet, compared to the vented 4.5ft^3/45hz F3 for the Eminence 3015LF.

With the 70$ i'm saving on the woofer, how about I step up to a 10" mid? Or should i just stick with the 8"?
Click to expand...

How do the sensitivity curves compare between the Dayton and the Eminence 15?
 
#9
fdeck said:
How do the sensitivity curves compare between the Dayton and the Eminence 15?
Click to expand...

The Eminence is 98db 1w/1m, the Dayton is 91db 1w/1m. Can blame that on the heavier cone of the Dayton.

Another driver i'm thinking about is the Peavey Low Rider 15" which is 94db 1w/1m; it has the same xmax as the Eminence 3015LF but it hits 40hz F3 in 3.5ft^3 vented... Here's a link:

[Invalid or Expired Link Removed]

So, should i go with the Eminence 3015LF, Dayton 18", or Peavey Low Rider 15"? The 18" would give me the most power handling, although it won't get as loud as the 15"s but it is cheaper. The Eminence would be the loudest but in a bigger cabinet with not as much extension, and the Peavey seems to be the middle ground... I'm not gigging right now, but may be within another year or two and it would be nice to get the cabinet in the 3.5-4ft^3 range...
 
#10
Well... I have to admit my personal tastes here. I find speakers with lots of low end extension to be pretty much unworkable in rooms that don't have the best acoustics. All of that low end bouncing around just turns into mud.

Also, if you are simultaneously getting into playing, gigging, and DIY'ing, a more mainstream design may be prudent. Most commercial bass amps have F3 in the range of 50 to 70 Hz. My DIY 12" is even higher. I think a safe bet for modern electric bass would be the 3015LF in a slightly smaller than optimal box, maybe even down to 3 cf. It will be more portable, and the lightweight driver will give you the impetus to build from 1/2" panels with bracing. Also, I think a 8" mid would probably be a good match to the 3015LF.

There are just so many people singing the praises of the 3015LF. Where to come up with the $70 difference? For now, you can dispense with casters, corners, handles, fancy jack plate, etc. Another thought is that you might actually save money by keeping the electronics simple with a passive x-over.
 
#11
All very good points fdeck. Thanks for your suggestions.

If i had unlimited funds i would just buy the Peavey and the Eminence and see which i liked better, but wouldn't we all... Since i'm relying on the experiance of others i'll stick with the Eminence 3015LF and put it in a 3.5ft^3 air space. That gives me a 50hz F3 according to winisd. If i find the need for more or less lowend i can add an eq to the rack or just use the tone controls in the preamp i'm building. Time to buy plywood! :hyper:

I'll hold off on the compressor, and if i find i need to save a bit more money i can use the active xo i use in my stereo setup for the testing phase. :bassist:
 
#14
Vin_MM_Sabre_79 said:
Why not build the compressor too withInvalid Link Removed?
Click to expand...

I've seen those before and i could build one, but i wanted all the different options a full rack unit would give me... I could just build one anyway to play with, they're cheap enough.

As for Bill F's designs, i've seen those also and considered them but i'm looking for a more standard/mainstream cabinet for this build. In the future i will no doubt try some of his cabinet designs.
 
#15
I have a pair of PA cabs that are just about the same size as my Peavey 1516 cab. I contacted Eminence directly, gave them the anb dimensions, and they put everything into their cab modeling software. One of the speakers they came back with for good clean low end in that size cab was the Eminence Delta 15LFA. I ordered them online and they sound great in those cabs. I found them cheap here and had no problems with my order:

http://www.audio-discounters.com/delta-15lfa.html
 
#17
greenboy said:
Hey all, starting from post #725 in Boutique 3-way 115 and 215 on a budget: Part II, I'm providing plans to build a really top performing 2- or 3-way cab that's like high quality PA only optimized for bass guitar use. You are all welcome to check it out. It's my gift to talkbass : }
Click to expand...

Thanks for pointing me there greenboy but i think I'd rather use the Eminence Alpha 8" midrange. It needs a bit more space in the cabinet but it will be give me more wiggle room with the xo frequencies. I could run the 15" all the way up to 1khz, or i could cross it at 200hz to the 8" and anywhere in between. Both the Beta and the Alpha 8"s have a pretty flat frequency response.

Also, if you are going to use 5/8" material i hope you plan on bracing the cabinet heavier than what you have in the diagrams. I believe that cabinet will resonate badly, and which will hurt the sound, that is unless you the boomy midbass sound of cabinet resonance. I'm going to use 3/4" birch ply, with a lot of bracing.
 
#18
Stromrider said:
Thanks for pointing me there greenboy but i think I'd rather use the Eminence Alpha 8" midrange. It needs a bit more space in the cabinet but it will be give me more wiggle room with the xo frequencies. I could run the 15" all the way up to 1khz, or i could cross it at 200hz to the 8" and anywhere in between. Both the Beta and the Alpha 8"s have a pretty flat frequency response.
Click to expand...

I've had 'em. The 18 Sound 6ND410 pounds 'em and leaves 'em in the dust (my opinion and that of others who have tried it). There's absolutely no reason to cross over as low as you propose when the woofer can handle that better with no fear of blowing it. Secondly, the 18 Sound has way nicer off-axis response, is way more sensitive (easily equivalent to two of those), and weighs less than 2.5 pounds, and can handle power better as long as you don't try to cross over too low. It also reaches higher, which even for some tweeter-likers who have heard it agree can obviate the need for a tweeter.

Also, why run both drivers in some of the same bandpass? Really don't gain much, and the imaging clarity/coherence is considerably degraded.

Also, if you are going to use 5/8" material i hope you plan on bracing the cabinet heavier than what you have in the diagrams. I believe that cabinet will resonate badly, and which will hurt the sound, that is unless you the boomy midbass sound of cabinet resonance. I'm going to use 3/4" birch ply, with a lot of bracing.
Click to expand...

Actually there is a secondary bracing system that ties in, but I doubt it will even be needed so I haven't published it. Those are aircraft-drilled girdle bracing - on mine they slide in on dovetails.

More to consider: the shelf and the midrange box themselves also provide considerable bracing. That's already been proven by the way, on the Carvin LS1503 which is 1/2" 9-ply and is rock solid. Know your glues.
 
#19
greenboy said:
I've had 'em. The 18 Sound 6ND410 pounds 'em and leaves 'em in the dust (my opinion and that of others who have tried it). There's absolutely no reason to cross over as low as you propose when the woofer can handle that better with no fear of blowing it. Secondly, the 18 Sound has way nicer off-axis response, is way more sensitive (easily equivalent to two of those), and weighs less than 2.5 pounds, and can handle power better as long as you don't try to cross over too low. It also reaches higher, which even for some tweeter-likers who have heard it agree can obviate the need for a tweeter.

Also, why run both drivers in some of the same bandpass? Really don't gain much, and the imaging clarity/coherence is considerably degraded.
Click to expand...


I'm using an active filter between the two drivers, LR4 24db/octave. "Imaging" is a psychoacoustic effect of a stereo system playing recorded/mastered music. Not sure where that ties in with a mono bass cabinet. I design phase coherent passive filters for the hifi speakers i design and build so the drivers integrate well, so the system can "image" well.

Thats not necessary in a bass cabinet, or even most PA cabinets considering the distance between the listeners, the cabinets themselves and the fact that most sound guys just do a mono mix.
 
#20
Hey Stromrider,

Imaging, as in multiple sources with differing responses in close proximity operating partly in the same passband, as you have when a driver is stopping at 1K Hz while the other is starting at 200 Hz (or whatever).

I use asymmetrical SMS-driven crossovers too - but only to optimize actual response of the two drivers - not to get them both reproducing some of the same frequencies. Doing that smears the sound, and contributes some additional odd polar anomolies.
 

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