Plastic cabinet EV zlx15

[jerry88lee]

I'm a solo keyboardist who plays touch bass, keys & vocals. I recently switched from my JBL Mpro 212 cabs (wood) to the EV because the 12" JBLs just weren't cutting the bass. The passive EVs are a DRAMATIC improvement overall & ESPECIALLY the bass. But there is a persistent very high pitched resonance as well as some other unwanted noises....I use one cab as a monitor so both are very close. There are no other blatant problems. I do restaurants, etc.

I made some very slight high end eq adjustments (Mackie 808s) which have helped, but I realize that these plastic cabs may be the cause. I paid VERY little for the EVs, but especially because of the bass would not return to the JBLs.
Any suggestions? I just have a 9 band EQ, but I do have 40 yrs experience. Oh, the bigger EVs weigh 8 lbs less too...and I'm 73....
Old saying: "You can't make a silk purse from a son's ear". Thanks for your comments....

 

[WayneP]

Since adjusting the EQ on the Mackie helped, you might try using the 9-band EQ to "fish" for a frequency that better matches what you're hearing. I'm guessing the frequency in question is making the cabinet resonate.

If the 9-band EQ does help, you might try moving up to a parametric equalizer. It would be able to "nail" the problem frequency and notch it with surgical precision.

Regards,
Wayne A. Pflughaupt

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[agedhorse]

Maybe first be sure that there isn't something wrong with speaker first?

A high resonance is not normal from that cabinet.

 

[jerry88lee]

Since adjusting the EQ on the Mackie helped, you might try using the 9-band EQ to "fish" for a frequency that better matches what you're hearing. I'm guessing the frequency in question is making the cabinet resonate.

If the 9-band EQ does help, you might try moving up to a parametric equalizer. It would be able to "nail" the problem frequency and notch it with surgical precision.

Regards,
Wayne A. Pflughaupt

Official Pedulla Club #45 Unique Arrangements of Hymns, P&W Standards, and Original Tunes
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Thank you! I will give a different EQ serious consideration!

 

[agedhorse]

Thank you! I will give a different EQ serious consideration!

Re-read post #3

 

[eniac]

EV says to run a 40 Hz HPF with those speakers. Are you doing that?

I've also found that keyboard bass players can be murder on LF drivers when their left hands go "too far left", i.e. into a region that most speaker systems were never designed to handle. Especially when the players crank the bottom end to compensate for lack of boundary reinforcement when the speakers are pole-mounted.

 

[eniac]

Addition: You said you paid very little for the EVs. Does that mean they're second-hand? If so, there's a chance they've been hammered by the previous owner(s).

 

[jerry88lee]

EV says to run a 40 Hz HPF with those speakers. Are you doing that?

I've also found that keyboard bass players can be murder on LF drivers when their left hands go "too far left", i.e. into a region that most speaker systems were never designed to handle. Especially when the players crank the bottom end to compensate for lack of boundary reinforcement when the speakers are pole-mounted.

I don't know what a 40 HPF is!..please let me know...but I am aware that my left hand bass is very demanding on speakers....I try to limit its volume & I almost never boost the bass...i generally play the eq flat..also volumes in restaurants are mild to moderate. These 15s are dramatically better for touch bass though. You mentioned poles....I use 1 on a pole for a main & 1 aside me on floor for monitor.....you are right...the monitor provides much more bass....the combination of the 2 does what I need.

I think that if I can reduce the tiny unwanted high freq noises through eq I will be good. Thank you....

 

[WayneP]

The short, minimal-tech answer: A high pass filter (HPF) removes the bass frequencies. In the case mentioned, only frequencies 40 Hz and above would be played through the speakers. Frequencies below 40 Hz would be reduced substantially.

An easy way to remember:
High pass filter only "passes through" the high frequencies.
Low pass filter only "passes through" the low frequencies.

Regards,
Wayne A. Pflughaupt

Official Pedulla Club #45 Unique Arrangements of Hymns, P&W Standards, and Original Tunes
Make Your Own Cables: A How-To Guide
Administrator, Official Heartfield Club #36
Administrator, Official Tobias Club #133
Administrator, Official Pre-Gibson Tobias Owners Club
Administrator, Fretless Club #943
Big Cabs Club #23
My Basses
My Rig: Stage and FOH Friendly
Official Pedulla Club #45

 

[Redbrangus]

You can trying tweaking EQ and... blah, blah, blah. But the fact is, with those dime store speakers, you don't have the right tool for the job. If you want to be assured your low notes don't crap out, you need more robust speakers at anything but the most modest levels. And it doesn't much relate to anything like "12s won't cut it -- you need 15s." The JBL speakers you cited are entry-level speakers and really aren't representative of what JBL pro products are like. I'd recommend a pair of JBL SRX 812s, which can be had in powered or unpowered versions.

A high-pass filter would certainly help; it's possible your speakers have that capability.

 

[eniac]

Hey Red, I think those are passives, so he'd have to HP somewhere upstream.

Anyway, I was thinking he could remove the grilles, start playing the keyboard to create the resonance, and put his ear to the woofer and then the horn while playing. Doing that might help to isolate the source to one or the other. This noise might be coming from a blown compression driver.

 

[jerry88lee]

The short, minimal-tech answer: A high pass filter (HPF) removes the bass frequencies. In the case mentioned, only frequencies 40 Hz and above would be played through the speakers. Frequencies below 40 Hz would be reduced substantially.

An easy way to remember:
High pass filter only "passes through" the high frequencies.
Low pass filter only "passes through" the low frequencies.

Regards,
Wayne A. Pflughaupt

Official Pedulla Club #45 Unique Arrangements of Hymns, P&W Standards, and Original Tunes
Make Your Own Cables: A How-To Guide
Administrator, Official Heartfield Club #36
Administrator, Official Tobias Club #133
Administrator, Official Pre-Gibson Tobias Owners Club
Administrator, Fretless Club #943
Big Cabs Club #23
My Basses
My Rig: Stage and FOH Friendly
Official Pedulla Club #45

Thank you....will check it out. I realize that if I used heavy wood quality mains I would not have the noise issues as I never did with good equipment. At age 73, I no longer schlep those things around any more! So we adapt!

 

[eniac]

Edit: Your EVs DO have HPF capabilities. Here's a link to the owner's manual: RTFM

You sure about that? The OP said they're model zlx15: https://products.electrovoice.com/na/en/zlx-15/

And he also describes them as "The passive EVs".

And his previous speakers were JBL MP212: https://jblpro.com/en-US/products/mp212
...suggesting a direct replacement of the JBLs by the EVs.

 

[Redbrangus]

Hey Red, I think those are passives, so he'd have to HP somewhere upstream.

Anyway, I was thinking he could remove the grilles, start playing the keyboard to create the resonance, and put his ear to the woofer and then the horn while playing. Doing that might help to isolate the source to one or the other. This noise might be coming from a blown compression driver.

You're right, of course. There IS a powered version, but this ain't it. And I 'get' the issue of cabs being too heavy. There probably are some plastic cabs with neodymium drivers that would do the job adequately -- I don't think these are them. Another solution might be still smaller cabs supplemented with a compact dedicated sub-woofer, but then that's more gear to lug around.

 

[agedhorse]

Thank you....will check it out. I realize that if I used heavy wood quality mains I would not have the noise issues as I never did with good equipment. At age 73, I no longer schlep those things around any more! So we adapt!

It has nothing to do with wood versus plastic-composite. There are composite cabinets that are far better than wood cabinets.

If you are unwilling or unable to do any basic troubleshooting to identify a specific problem with your current speaker, then buying a quality new speaker ur really your only other practical option.

JBL PRX-812 is a very good keyboard speaker, and in the powered version will simplify your setup.

 

[Transistor]

You could try a frequency sweep and see if there's a peak. Two mobile phones might do the job.
- Install a frequency generator on one phone and play that through the speaker. (Use a sinewave. Any other waveform will introduce harmonics, meaning you won't know which is causing the problem.)
- Install an audio level meter on the other and measure the sound level as you sweep through the low octaves. (Measuring at a distance from the cabinet sounds like a good plan but may pick up room resonances so you'll have to experiment.)

If you find a problem then you might be able to fix it with a single-band parametric equaliser.

Something like AudioTool for Android might be able to generate pink noise (equal energy per octave*) and plot the response as well. It's not quite clear from the "trailer" YouTube link on that page.

* White noise is equal energy per unit frequency band - so it sounds very hissy.
Pink noise is equal energy per octave and so the low frequencies should sound as loud as the highs.

 

[Guitalia]

Hey, jerry88lee:

You've apparently been ignoring the posts written by agedhorse, or at least haven't acknowledged them. Which was puzzling to me, until I noticed that you apparently joined this forum just today.

So:

FYI, agedhorse is easily one of the most experienced and respected contributors to this forum. He has designed high-end amplifiers, speakers, and other music electronics equipment for decades.

Since you're 73, you'll likely get the allusion when I liken agedhorse weighing in on your thread topic to the moment in the movie Annie Hall when Woody Allen pulls Marshall McLuhan out from behind a wall to confirm Allen's interpretation in an argument on McLuhan's media theory.

Allen, breaking the fourth wall, then says to us: "Wouldn't it be great if life was like this?" On this forum, life is indeed like that, every once in a while, when agedhorse or Wasnex or a couple of other members of the Talkbass brain trust show up. Thus, I suggest rereading his posts in this thread in that light.

 

[Mike Caldwell]

Yes to a high pass filter maybe even closer to 50hz and YES to sorting out the source of noise your hearing.

Buying used passive speakers can be a big gamble as to what they have had to endure before you got them, the amplification signal chain they were used / abused with could be all over the place.
By and large your average music store speaker buyer is going to push a speaker beyond what it can do.

Your Mackie mixer does have a high pass filter, the button is to the lower left of the EQ's. From what I just looked up is at 75hz, that's a little high for what your doing but better than blowing up your speakers.
Just how loud are you running these?

 

[Wasnex]

The RMS power rating is 250W and the sensitivity is fairly low at 96dB 1W/1m. Is it possible that you are simply asking too much of them?

How do they sound with program material VS keyboard? I.E. could the sound source be the problem and the EVs are just better at revealing it.

Could the horn drivers be partially blown? I bought some used EV SX300s and one of the horns had some distortion. I thought maybe some debris had gotten inside the phase plug and pulled the diaphragm. As I lifted the diaphragm out of the voice coil slot, it unwound like a slinky.

Another possibility is the previous owner blew the horn drivers and either replaced the diaphragms or entire driver with garbage.

 

[eniac]

I bought some used EV SX300s and one of the horns had some distortion. I thought maybe some debris had gotten inside the phase plug and pulled the diaphragm. As I lifted the diaphragm out of the voice coil slot, it unwound like a slinky.

Had a similar experience in the mid 1970s with some Altec 1204B cabs we were using. One pair began sounding rough/buzzy at the high end. Turns out the 808 (IIRC) drivers had no acoustical loading caps. I did what research I could, and read somewhere that the earliest drivers were shipped without them, and Altec began adding them later on to increase power handling. I can't remember where I read it. Anyway, I installed new diaphragms and loading caps, and those horns sounded better than they ever had.

The funny part of the story is how I obtained the caps. Since I couldn't find them locally, I mailed a typewritten (real Adler typewriter) letter to Altec directly, asking for the pair I needed, and I put a $10 bill in the envelope along with the letter. A couple weeks later I got a small box with the caps in them. I'd already picked up the diaphragms in a repair shop about 15 minutes away but they didn't have caps in stock and told me I'd have to wait until the next big Altec order went in, which would be who knows when.