8" speaker for bass guitar

[Music is life]

I was wondering if there is actually a good 8" speaker out there that would be good for bass guitar in lets say a 4X8" or 8X8" cab.
Looks to me that most just don't have enough Xmax but I could be way off base (sorry for the pun).

I do not play bass guitar but may make a cab some day.
Any thoughts?

[billfitzmaurice]

I was wondering if there is actually a good 8" speaker out there that would be good for bass guitar in lets say a 4X8" or 8X8" cab.
Looks to me that most just don't have enough Xmax but I could be way off base (sorry for the pun).

I do not play bass guitar but may make a cab some day.
Any thoughts?
IMO no, there isn't. Good bass guitar drivers start at the ten inch size.

[PunkSweeper]

Just earlier today I was thinking that three of these (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-833) and one of these (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=294-654) would make a neat 4x8, sealed, bi-amped and equalized.

That way you'd have impressive lows and snarl in a a smallish enclosure. It might even beat...a 1x12.

[wg_ski]

The midrange is a good one. The way to get the tone of an 8" with some low end grunt *is* a biamped combo. But I think everyone here would question the choice of the "woofer". That woofer is a 5 1/4! not even an 8. And only 82 dB/W. How many would you need to get both a reasonable impedance and 90-some dB/watt? 32? 64? No free lunch.

[Music is life]

OK! So not very feasible on the 8's.

Next question then.
What 10's are recommended and is cross firing an option?

As an experiment I crossfire 4 alpha 6a's (2 high 2 wide), at 45% with extended sides coming out forming a horn (straight sided) that is to 26" wide at the front and 16" high at the front (14" high at the back). No compression on the drivers just mounted for easy access from the front. This with a 1" wide slot loaded port tuned to 104Hz place between the drivers at the back of the horn. 1.3 cu ft encloser, with a compression tweeter crossed over at 3000Hz.

Would like to have crossed it over at 2500Hz or even a little lower but using an Apt 80 with the horn taken off and placed in front of this horn:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=294-618

Yes I know it doesn't fit in that horn, but made it fit LOL! And prefer the sound.
Found the overall sound of this combination very nice and it does close to 104db with one watt. Put no attenuation on the tweeter. As mentioned could use a lower crossover.
Crossover at 100Hz at the low end to a sub.

Now brought all that up to say that I might like to try the same thing with some 8's or 10's for bass guitar cross firing, reflex port at the back of the horn for a small overall, maybe 3db increase in sensitivity. You can see why 8's would have been better as they would fit further back in more comfortably.

So is cross firing 10's for bass guitar a nutty thing to try? Would it be a waste of time and effort? It's fun to experiment but not just to waste time.

[PunkSweeper]

The midrange is a good one. The way to get the tone of an 8" with some low end grunt *is* a biamped combo. But I think everyone here would question the choice of the "woofer". That woofer is a 5 1/4! not even an 8. And only 82 dB/W. How many would you need to get both a reasonable impedance and 90-some dB/watt? 32? 64? No free lunch.

My bad, I fixed the link.

[wg_ski]

On paper, the 8's might work - if you drive them with 500W of class D amp. I wonder how much power they would really take before coming apart. Probably not 120W of instrument-speaker duty each.

Even instrument-specific 10" bass drivers have limits. Take a 4x10 loaded with Delta 10's and the suspensions get pretty ragged out after months of use, even if they seem to "take it just fine" initially. It's a cash cow for the reconers.

[PunkSweeper]

On paper, the 8's might work - if you drive them with 500W of class D amp. I wonder how much power they would really take before coming apart. Probably not 120W of instrument-speaker duty each.

Even instrument-specific 10" bass drivers have limits. Take a 4x10 loaded with Delta 10's and the suspensions get pretty ragged out after months of use, even if they seem to "take it just fine" initially. It's a cash cow for the reconers.

Let's not forget the premise of building a bass amp with 8's shall we? ;)

[Music is life]

If anyone has an opinion.
Is cross firing 10's a good idea and if so what angle would you try (for bass guitar)?

[billfitzmaurice]

If anyone has an opinion.
Is cross firing 10's a good idea and if so what angle would you try (for bass guitar)?
It's not, because for a given cab footprint you'll seriously reduce cabinet volume, and that reduces low frequency response and output. And having the tens side by side reduces the angle of dispersion within the bandwidth where they're close enough to each other to mutually couple. Run the tens vertical for the best dispersion within their bandwidth, which means to 2.5kHz maximum, if you need to go higher cross to mid driver(s).

[Music is life]

It's not, because for a given cab footprint you'll seriously reduce cabinet volume, and that reduces low frequency response and output. And having the tens side by side reduces the angle of dispersion within the bandwidth where they're close enough to each other to mutually couple. Run the tens vertical for the best dispersion within their bandwidth, which means to 2.5kHz maximum, if you need to go higher cross to mid driver(s).

That's what I was afraid of.
Perhaps better then simply to start with a good 15 and cross over to a good midbass?
Maybe something like this:
(1) 3015LF
(4) Alpha 6a (vertical and connected for 8 ohms)

Crossed at 3 or 4 hundred.
Already have almost all the parts to build the above.

Would 8's be better?
Would that need a tweeter?

And thanks for the input.

[billfitzmaurice]

That's what I was afraid of.
Perhaps better then simply to start with a good 15 and cross over to a good midbass?
Maybe something like this:
(1) 3015LF
(4) Alpha 6a (vertical and connected for 8 ohms)

Crossed at 3 or 4 hundred.
Already have almost all the parts to build the above.

Would 8's be better?
Would that need a tweeter?

And thanks for the input.Use a tested and tried design. Like the one here:
http://www.talkbass.com/forum/showthread.php?t=586013

Or here:
http://www.billfitzmaurice.info/Omni15.html

[Music is life]

Use a tested and tried design. Like the one here:
http://www.talkbass.com/forum/showthread.php?t=586013

Or here:
http://www.billfitzmaurice.info/Omni15.html

Good advice Bill.
Got a bit of a stubborn streak so to speak. Like to learn from others but still like to experiment a bit.

I've got a couple of free 3012lf's and a couple of free beta 8's and some apt 80's hanging around.
Might try a 3012lf with a beta 8 some time and ask one of my bass playing friends to give it a whirl.

Now that my original ideas doesn't seem to have any real potential that is.
Your Omni 15 looks like a real beast!

Thanks for the input.

[Music is life]

Happy Holidays everyone! :)

[kduggan]

You could use non pro sound woffers. I would think 4 dayton classic 8's would perform quite well as bass drivers at a reasonable level. you can cross to a compression driver at around 2.5K without issue and have a really strong bottom end properly tuned all the way down to the mid 30's

[billfitzmaurice]

You could use non pro sound woffers. I would think 4 dayton classic 8's would perform quite well as bass drivers at a reasonable level. Between their low sensitivity and displacement four Classic Eights would be severely outclassed by a single pro-sound twelve. They're simply the wrong tool for the job.

[kduggan]

Between their low sensitivity and displacement four Classic Eights would be severely outclassed by a single pro-sound twelve. They're simply the wrong tool for the job.

I agree the 8 in driver is not the best choice. I was just trying to suggest a different way to skin the existing cat.

[Music is life]

First of all, thanks to everyone for the input so far.

I've been thinking about this for a while now.
Let me know what you think.

(1) 3015 lf
(4) Alpha 6a vertically arrayed.
Tweeter optional.

Crossover 250 Hz 18 db per octave.
If this makes sense might build one this spring for trial.

I have the speakers on hand but would need to order parts for the passive crossover.

Thinking, easy to build, easy to put another 1 or 2 on top with no comb filtering [box 27" high with woofer next to mids], might not need a tweeter, nice 99db sensitivity, nice full range option with tweeter.

Nothing fantastic about it, but perhaps nice and linear, and practical, hopefully, and if not do let me know.

Any thoughts?

[billfitzmaurice]

First of all, thanks to everyone for the input so far.

I've been thinking about this for a while now.
Let me know what you think.

(1) 3015 lf
(4) Alpha 6a vertically arrayed.
Tweeter optional.

Crossover 250 Hz 18 db per octave.
If this makes sense might build one this spring for trial.

I have the speakers on hand but would need to order parts for the passive crossover.

Thinking, easy to build, easy to put another 1 or 2 on top with no comb filtering [box 27" high with woofer next to mids], might not need a tweeter, nice 99db sensitivity, nice full range option with tweeter.

Nothing fantastic about it, but perhaps nice and linear, and practical, hopefully, and if not do let me know.

Any thoughts?There's no reason to cross a direct radiating 3015LF lower than 800Hz, nor to use more than two Alpha 8s with it.

[Music is life]

I've moved away from the bass gutar speaker project temporary.
Working on the this one as mentioned above:
Quote:
As an experiment I crossfire 4 alpha 6a's (2 high 2 wide), at 45% with extended sides coming out forming a horn (straight sided) that is to 26" wide at the front and 16" high at the front (14" high at the back). No compression on the drivers just mounted for easy access from the front. This with a 1" wide slot loaded port tuned to 104Hz place between the drivers at the back of the horn. 1.3 cu ft enclosure, with a compression tweeter crossed over at 3000Hz.
End quote.

Have rebuilt it to try and get a little better sound.
It starts out at a very slightly tighter angle and then expands just beyond the drivers to about 85 degrees to try and get a little more depth in the horn before it gets too wide.

Loaded the alpha 6a from the inside of the enclosure (still the same cross fire set up) to put them in a little compression to start with, with about 2" by 3" rectangle opening.
Experimenting with about a 26" to 27" width.
Crossing over now 18db per octave at 2400Hz to a B&C DE10-8 and B&C ME10 horn. Attenuated 4db. Could use 1,2 or 4 of these by cutting off the horn lips at top and bottom. It's about 105db with one watt.


Trying to re-tune the small bass hump from the reflex design to compensate from the lack of horn length but at the same time avoid coloration in the male voices because the small bass hump does not match exactly the unloading of the horn in the 200 to 250Hz range. This is really a pain!

So far a 120Hz crossover (on my receiver) sounds better than trying for 100Hz but that might change.
The surprises at this point is how much a difference a very small change makes. An inch difference forward or backward on tweeter placement can change the phase.
A half inch more or less on horn length.
A few cubic inches less or more in the enclosure.
A slight retuning of the slotted port.

Will be playing with this one for a while.

When the crossover was changed from 2nd order to 3rd order this difference was quite audible. Perhaps because, of the time difference between the alpha 6a's and the tweeter. So will try forth order next to keep the frequency where they both contribute to a minimum.
Also placed a 1.5" wooden round dowel vertically near the back of the horn at the center juncture where the cross firing alpha's sound meets together (so to speak). This really helped the openness of the sound of the horn and I do not sense a degradation is sound quality. This might be a good idea for other cross firing applications, don't know. [Someone might want to try this out on cross firing tweeters for example like maybe a small wooden dowel at the angle of convergence. Just an idea.]

Also I do not have enough "poly" caps for this crossover frequency, and I'm sure that this will affect the tweeter's quality of sound. So gotta order some more parts when I've settled on the design.

Question then:
How much of a difference can one expect with better caps?

[Randy L]

Pictures are worth a 1000 words! Post some up please! :D

[Music is life]

Pictures are worth a 1000 words! Post some up please! :D

A little messy as it's still in prototype stage.

[Music is life]

A little messy as it's still in prototype stage.
This was a great experiment, but I've abandoned it at least for now.
It seems that the cross firing and the reflex combined into the same horn may have created problems in the midrange. Both "smear" and dispersion issues.
Great learning experience.

[billfitzmaurice]

This was a great experiment, but I've abandoned it at least for now.
It seems that the cross firing and the reflex combined into the same horn may have created problems in the midrange. Both "smear" and dispersion issues.
Great learning experience.That resembles a Danley Unity. The engineering of those is daunting, and venting the chamber into the horn adds another layer of complexity.

[Music is life]

That resembles a Danley Unity. The engineering of those is daunting, and venting the chamber into the horn adds another layer of complexity.

I've got a delta pro 12 hanging around. Think I'll play with it instead for a while. A little less complexity. :)
And I find its midrange astonishingly good. Especially behind a horn.

[Randy L]

This was a great experiment, but I've abandoned it at least for now.
It seems that the cross firing and the reflex combined into the same horn may have created problems in the midrange. Both "smear" and dispersion issues.
Great learning experience.

I think part of the fun IS experimenting. I've played around and ended up scrapping quite a few designs and construction methods.

[AMC]

I've got a delta pro 12 hanging around. Think I'll play with it instead for a while. A little less complexity. :)
And I find its midrange astonishingly good. Especially behind a horn.

I think the whole Delta Pro line has very good midrange, The 15 I have is great, for any size driver, let alone a 15. These were designed mainly for that it seems, as they don't even try to produce large levels below about 80Hz.

[Music is life]

I think the whole Delta Pro line has very good mid range, The 15 I have is great, for any size driver, let alone a 15. These were designed mainly for that it seems, as they don't even try to produce large levels below about 80Hz.

I'm surprised by the mid range quality. It's crossed over at 2400Hz.
But it won't do much below 120Hz the way I'm using it.

Where do you have your 15 crossed over?

[AMC]

I'm surprised by the mid range quality. It's crossed over at 2400Hz.
But it won't do much below 120Hz the way I'm using it.

Where do you have your 15 crossed over?

Right now I don't, I am using it in a new box for my bass, and just run it full range. It's an experimental thing. On thing I did do in it's previous box, I had a 6db/oct HIGH PASS x-over set at about 40 Hz, just to protect it from over excursion below the port. Highly recommended, seems to control a lot of the flabbiness 15's can sometimes have. As far as your 12, if it's like the 15's at all, it has to be a big box before it will get much bass, and then your power handling drops way down. But if you can get 100Hz out of it, that should be all you need.

[Music is life]

Thanks amc, your input was helpful.
I'll try that 15 out at a later date. It looks promising for what I'm trying to do.
That 15 reminds me a bit of an EV sp15a that I used to have many years ago.
Man did that thing play loud with my NAD 3080
Now I'm showing my age. :)

[AMC]

Thanks amc, your input was helpful.
I'll try that 15 out at a later date. It looks promising for what I'm trying to do.
That 15 reminds me a bit of an EV sp15a that I used to have many years ago.
Man did that thing play loud with my NAD 3080
Now I'm showing my age. :)

That's interesting, because as I understand it, it was modeled to be like the EV. I would like to know if anyone has tried the Deltalite 15, wonder how it stacks up. Love the idea of neo drivers.