Crossover/multiple enclosure question...

[BritFunk]

OK, folks, buckle up - I'm in unfamiliar territory and have a lot of what might be really dumb questions.

First off, a bit of background - I play five-string fretless and six-string fretted Ibanez basses. My amp is an Ashdown RM-500 Rootmaster. I have been running it with a Hartke Hydrive 112, switchable from 4 to 8 ohms.

I recently obtained a Peavey 1x15 cabinet that has been modded to hold an 18", and it currently contains a Peavey Black Widow (1808-8 sps bwx) speaker, no crossover - just a single 1/4" input (8 ohms).

I ran them both together at a jam session, and WOW did that rig sound great.

That said, I know I am not getting max performance out of these cabs, and am thinking a crossover would be a reasonable fix (the 18" allegedly handles all the way up to 1kHz, but that might be a little optimistic).

I will probably run just the Hartke alone at 4 ohms for 75% of gigs, but like the option of a larger cab for moving air at outdoor shows, etc. It would be ideal to have the Hartke run full-range if used individually, but when the 18" is incorporated the frequencies would be divided to the cabinet best able to handle them.

Cutting to the chase, my question is essentially this: of the two following wiring scenarios, is one preferable to the other, and why?

#1 - install a passive crossover in the 18" cabinet, crossed over at or below 1 kHz, and install a second jack to run out in parallel to the Hartke with everything above those frequencies.

#2 - use something like a Rolls SX21 crossover in the effects loop of the Rootmaster, and run the low frequencies out to a second amp powering just the 18", while the higher input is routed back into the Rootmaster's "effects in" jack.

Again, I see either of these as workable, but is one preferable to the other and why? More versatile, etc.? I did really like the idea of the Rolls SX21, mostly because I could tweak the frequency in real-time until I found the ideal crossover point.

Other suggestions on how to handle/better handle this situation?

Yes, I know the 18" in the 15" cab isn't ideal. It was stupid cheap, so I'm not complaining.

Any advice would be appreciated!

- Kurt

 

[Redbrangus]

WOW did that rig sound great.

No offense intended, but it sounds to me like you're making things overly complicated. I doubt the result of what you're proposing would be worth the effort...that is, if I even understand what you're thinking. Is it that you want to use the 18 as the low half of a 2-way speaker system and the Hartke as the high part? While still retaining the ability to use the Hartke as a full-range system? Definitely not worth the effort IMO...just plug 'em together if you liked the sound of it.

 

[JRA]

i agree with Redbrangus : run them in parallel at 8ohms each = done. take two cabs when you want that thrill.


edit: of course a HPF treatment would tighten it all up!

 

[BritFunk]

That will work! And yeah, that would reduce the suck of the complications considerably.

I was under the impression that I *really* needed to reduce the high frequencies going into the sub, but hey - if it will handle it without creating an issue, I'll be perfectly happy not making this more involved that it needs to be! Thanks for the help!

- Kurt

 

[Bass_Pounder]

I was under the impression that I *really* needed to reduce the high frequencies going into the sub,
- Kurt

Just because it is an 18", it does not make it a sub. Especially when it is loaded into a cabinet that is too small for it.

As already said, run the 2 together full range and be done.

 

[Redbrangus]

You absolutely do not have to worry about high-frequency content going into a low-frequency speaker. Speaking very broadly, one should not run LF information through a specialized HF driver.

 

[Coolhandjjl]

Even if you crossover at 800Hz, using a 12” cab is a poor way to handle to highs. You’ll get beaming/lousy dispersion. At 800, all you need for the top is a 6” 18Sound midrange driver.

 

[BritFunk]

> Even if you crossover at 800Hz, using a 12” cab is a poor way to handle to highs. You’ll get beaming/lousy dispersion. At 800, all you need for the top is a 6” 18Sound midrange driver.

The 12" cab also has a switchable horn/tweeter, so the high end wasn't really a point of concern. I read a number of conflicting things online over the weekend about using 18" speakers for sound reinforcement, so thought I would come here to ask - I knew that if any community would have a real-world answer, it would be this one.

Thanks again!

- Kurt

 

[Wasnex]

OK, folks, buckle up - I'm in unfamiliar territory and have a lot of what might be really dumb questions.

First off, a bit of background - I play five-string fretless and six-string fretted Ibanez basses. My amp is an Ashdown RM-500 Rootmaster. I have been running it with a Hartke Hydrive 112, switchable from 4 to 8 ohms.

I recently obtained a Peavey 1x15 cabinet that has been modded to hold an 18", and it currently contains a Peavey Black Widow (1808-8 sps bwx) speaker, no crossover - just a single 1/4" input (8 ohms).

I ran them both together at a jam session, and WOW did that rig sound great.

That said, I know I am not getting max performance out of these cabs, and am thinking a crossover would be a reasonable fix (the 18" allegedly handles all the way up to 1kHz, but that might be a little optimistic).

I will probably run just the Hartke alone at 4 ohms for 75% of gigs, but like the option of a larger cab for moving air at outdoor shows, etc. It would be ideal to have the Hartke run full-range if used individually, but when the 18" is incorporated the frequencies would be divided to the cabinet best able to handle them.

Cutting to the chase, my question is essentially this: of the two following wiring scenarios, is one preferable to the other, and why?

#1 - install a passive crossover in the 18" cabinet, crossed over at or below 1 kHz, and install a second jack to run out in parallel to the Hartke with everything above those frequencies.

#2 - use something like a Rolls SX21 crossover in the effects loop of the Rootmaster, and run the low frequencies out to a second amp powering just the 18", while the higher input is routed back into the Rootmaster's "effects in" jack.

Again, I see either of these as workable, but is one preferable to the other and why? More versatile, etc.? I did really like the idea of the Rolls SX21, mostly because I could tweak the frequency in real-time until I found the ideal crossover point.

Other suggestions on how to handle/better handle this situation?

Yes, I know the 18" in the 15" cab isn't ideal. It was stupid cheap, so I'm not complaining.

Any advice would be appreciated!

- Kurt

IMHO if you like the sound with the 18 and Hartke just go with it. Unless you have tuned the cabinet to the 18" driver it will not perform well as a stand alone woofer. Better to share the load with another speaker that is properly designed.

I have quite a bit of experience biamping. A biamped rig can sound pretty decent if you use high quality components that are well matched. I don't mean to be disrespectful, but I would not describe the setup you are considering as high quality or well matched.

Additionally, although a biamped rig can sound decent, IMHO, a multi-way passive speaker from a designer like Greenboy or Duke at AudioKinesis will typically sound better. The reason is because a designer will put a lot of thought into making sure the crossover and speaker components are optimized/tailored to work perfectly together. When someone like you are I puts together a biamp rig, there is typically no real engineering involved. We buy off the shelf components randomly and throw them together in a system. The lack of engineering has a negative impact on the system's phase, frequency response, dispersion, etc.

The same issues occur when you use an off the shelf passive crossovers. There is no engineering involved to ensure it will work well with your speaker components.

If you have the cash and enjoy experimenting, by all means go ahead. Your results are going to be better if you buy the good stuff. I currently play around with a Klark Teknik DN9848E speaker processor that originally sold for almost $5000 and the results are way better than the simple $180 DBX and Ashley crossovers I used to use. Likewise the DBX and Ashley crossovers sounded better than some of the really cheap stuff I tried when I was younger.

 

[BritFunk]

My Friends,

If you have the cash and enjoy experimenting, by all means go ahead. Your results are going to be better if you buy the good stuff.

Naw, if I had an excess of cash I wouldn't be screwing around with secondhand mismatched components. ;-) I'm just a weekend warrior these days and as I mentioned, 75%+ of the time the little Hartke cab will handle things just fine. More than anything I was concerned with the 18" not being able to handle the HF and that it might create an issue or cause damage. The sound of the system was fine, at least by my ears and the guys I was working with. If the HF isn't gonna hurt the 18" we'll roll with what we got! Thanks!

- Kurt

 

[Bob_Ross]

the 18" allegedly handles all the way up to 1kHz, but that might be a little optimistic

It's even more optimistic to expect a Peavey Black Widow 18" to produce proportionate SPL anywhere south of ~55Hz, regardless of the enclosure...but especially one that's too small.

 

[Wasnex]

My Friends,



Naw, if I had an excess of cash I wouldn't be screwing around with secondhand mismatched components. ;-) I'm just a weekend warrior these days and as I mentioned, 75%+ of the time the little Hartke cab will handle things just fine. More than anything I was concerned with the 18" not being able to handle the HF and that it might create an issue or cause damage. The sound of the system was fine, at least by my ears and the guys I was working with. If the HF isn't gonna hurt the 18" we'll roll with what we got! Thanks!

- Kurt

The 18" is safe with HF, but may not necessarily sound great above a certain frequency range. The idea of the crossover is to limit the drivers to the range where they are safe and sound best, and to prevent multiple drivers from producing sound in the same frequency range, so there is no destructive interference to produce phasing/comb filtering. IMHO, if you like the sound, don't worry about it.

Ideally when you run multiple speakers, you want them to be exactly the same. But I have run an 18" and 12" before and it worked fine.

 

[Coolhandjjl]

> Even if you crossover at 800Hz, using a 12” cab is a poor way to handle to highs. You’ll get beaming/lousy dispersion. At 800, all you need for the top is a 6” 18Sound midrange driver.

The 12" cab also has a switchable horn/tweeter, so the high end wasn't really a point of concern. I read a number of conflicting things online over the weekend about using 18" speakers for sound reinforcement, so thought I would come here to ask - I knew that if any community would have a real-world answer, it would be this one.

Thanks again!

- Kurt

The point was that crossing at 800 or higher, a 12” cab makes for a lousy choice regardless of what’s inside. All that’s needed when crossing at 800 or higher is a 6” midrange driver in an enclosure the size of a half of a loaf of bread.

 

[micguy]

I’ll echo comments on your 18” “sub”. Bass cabinets are almost always smaller thsn ideal for low frequency extension. Put an even larger driver in there, and it’s probably very far from optimal - It’s entirely possible that your 12 goes lower than your 18.

 

[BritFunk]

The point was that crossing at 800 or higher, a 12” cab makes for a lousy choice regardless of what’s inside. All that’s needed when crossing at 800 or higher is a 6” midrange driver in an enclosure the size of a half of a loaf of bread.

Ah - makes sense. Apologies - I misunderstood your point initially - that does make sense now. Thank you for the clarification!

I think in the interest of simplicity I'll just run both cabs full-on at 8 ohms in parallel for the time being. If I start playing any serious number of serious gigs again anytime soon I'll look into more serious gear then.

Thanks again for the thoughts and advice!

-----
Kurt

 

[Eddie LeBlanc]

The problem is, if you have different cabinets, with very different SPL (Efficiency) Ratings, and Frequency Response curves then is is highly possible to create frequency issues where you don't want them. And no matter what you set a volume or tone control, may never rectify.
18s can be real boomy down low, and other smaller speaker cabs can't hold their own with them.

That was one reason people went to bi-amping with active crossovers in the first place.
So, need to really pay attention to differences in the cabs, and adjust according. And sometimes playing with just the tone controls won't get it, cause they roll tone on all cabs in a Mono configuration with one mono amp. An 18" moves a lot of air.
Currently I'm running cabs that are real closely matched in SPL efficiency and frequency response. Makes it real easy to dial in a sound for the room.