Subwoofer question??

AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
I agree that providing a strong input signal below the port tuning frequency is probably the easiest way to kill a ported sub.
However, I think you are not addressing frequencies above the port tune and how to ensure a proper balance between amp clipping (due to not enough amp power) and overloading the sub (due to too much power). Maybe I am over-complicating it, but using a 250 to 500W amp for a 500W rated sub seems like a broad brush for what I perceive as a matter of fine tuning!
I might believe that the manufacturers use some sort of limiters to provide frequency dependent output limits?

I look at active speakers like the JBL LSR-305's and what it takes for JBL to make them bullet-proof and think it is an amp with specific, customized parameters. A subwoofer may be less sensitive to these concerns, but I don't know about that!

Maybe @Ed Mullen could give us some idea of what they do on this count?
1. Regardless of what I'm watching or listening, I love Hearing and Feeling the bass, gotta have a lot of bass to SHAKE my room and everything (sofas, pillows) in my room like an EARTHQUAKE. I've never felt like I'm missing anything with a HPF of 20-30Hz. I've tried using HPF of 20Hz, 25Hz, and 30Hz. It seems the difference in the magnitude of the bass was minimal.

2. I've used from 60WPC (ATI amp) to 200W (ATI amp) to power my passive SX-1010 subs. Right now my ATI AT2005 amp is powering my RBH subs (1010s).

In my living room, the RBH SA-500DSP (500W into 4 ohm) external sub amp is powering the SX-1212 (bottom cabinet of the SVT towers).

3. But I think you have an excellent point about taking a RISK when you go with passive subs vs active subs. I guess because I've always used passive subs even with 60WPC amps and always had room-shaking-earthquake bass with my subs, I've taken them for granted. But there is a risk of blowing your subs.

In the end, the user has to weigh the risk vs benefits of using passive subs.

I've mentioned this several times on AH, but a friend of mine owned a brand new flagship SVS sub. He had to replace the amp on that sub TWICE in 3 years. Now I've hooked him up with the RBH SVT/R towers and SA-500DSP amps. He says the bass of the SVT/R towers are at least as awesome as his big SVS sub.

RBH sells Sub amps (SA-500DSP) that go with their Subs. So these amps were designed to work perfectly with their Subs. The only difference is that the sub is EXTERNAL.

Remember I used to own those Red Linkwitz Orion? They are Active speakers that require 8 amps per pair of speakers. Yet the amps are external (60WPC x 8Ch).

So perhaps sub (and speaker) companies could offer subs (and speakers) with external amps designed to work perfectly with their subs?

"Active" subs and speakers can still have EXTERNAL amps.

So sure, let's do all Active speakers and subs. But let's keep the amps external and SEPARATE for better reliability and easier replacements or repairs.
 
Last edited:
A

Andrein

Senior Audioholic
I think that it might be cheaper to just sell european subs and buy new ones when you land in US. Subs are usually very heavy and it can be expendive to move them over the pond.
 
C

CoryW

Audioholic
My Rythmik E15HP has a switch to accommodate both voltages, my Outlaw X13 Ultra does not! Most ID websites offer photos of the amp panel, so it is not too hard to verify for a particular model.

There are pros and cons to subs with built-in plate amps. I assume you have heard many pros of passive sub with external amp. One major advantage of built-in amps with the sub is that the amp is selected specifically for the sub so as to limit output before damaging the sub (or even making bad sounds). As Tom V. of PSA says about his subs: "They are pretty much bullet proof - but don't take that as a challenge!"

Even the low priced ($150 MSRP) Dayton Audio SUB1200 has an amp selected specific to its driver/design such that Jim Wilson had this to say in his review:

This is the advantage of letting the manufacturer choose an amp specifically for the sub. You want the amp to limit itself before the drivers are over-driven so even though you may not get the deepest bass at full volume, you are not hearing a loss of composure.
Of course, a better sub will take much more before reaching limits as compared to the SUB1200, but it is nice to have an expert take care if the amp selection.
The RBH fan boys and DIY guys can tell you how they best deal with concerns over what happens if/when their systems get pushed to the limit.
Kinda funny on this thought, I had my crown bridged at 1500 watts, powering a single RBH 1010sen/r sub with freakish results. I asked the sub designer about concerns of bottoming the driver out (observed massive excursions). He smiled, and said I will never bottom or damage the 10” reference driver. I started to argue the point , he repeated the statement. I am using RBH SA-400 amps that put me in the sweet spot. I’ve never been able to push the subs into breaking up because I think they would collapse my basement first. Everything came to life, the subfloors., wall board, windows, doors....all vibrating wildly. Scared the hell out of me.
 
KEW

KEW

Audioholic Overlord
Kinda funny on this thought, I had my crown bridged at 1500 watts, powering a single RBH 1010sen/r sub with freakish results. I asked the sub designer about concerns of bottoming the driver out (observed massive excursions). He smiled, and said I will never bottom or damage the 10” reference driver. I started to argue the point , he repeated the statement. I am using RBH SA-400 amps that put me in the sweet spot. I’ve never been able to push the subs into breaking up because I think they would collapse my basement first. Everything came to life, the subfloors., wall board, windows, doors....all vibrating wildly. Scared the hell out of me.
Very interesting post. Did he explain why you could never damage it? I would really like to understand that!
 
lovinthehd

lovinthehd

Seriously, I have no life.
It wouldn't be wise to try, but I bet you'd be surprised at how much abuse they will take.
From the manual:

Maybe I am overly optimistic, but you know somebody is going to use these studio monitors as on-stage personal monitors or some such. I just think of pro-audio as being a tremendously abusive environment and believe most pro-audio gear is built with safety limits in mind. If you are going to be in the pro-audio business, you don't want to be the company that gets a reputation for failures even if it is for BS applications.

I know my Focal Pro Audio studio monitors simply shut off when I maxed them out. Scared the crap out of me, and it was one hell of a sigh of relief when I shut them off, waited 60 seconds (probably not needed, but I wanted to give them every opportunity to work), flipped them back on and they were like new!
Never saw that bit in the manual. It might depend on source/signal level, too. Might try to find out what the specifics of that test is.....
 
C

CoryW

Audioholic
Very interesting post. Did he explain why you could never damage it? I would really like to understand that!
It had to do with the construction of the surround and spider, and the way coil sticks half way out of the magnetic gap, also the magnets used are really large thick ceramic magnets, double stacked and a large bumped back plate. I did a test a while back when I had my crown amp in 1500 watt bridged. I started a test track that starts at 10 hz. It was dead silent yet my grandson said he felt funny. When I pulled the grill off, I saw both woofers doing the most freakish excursions I have ever seen. The port was moving air like a high speed fan. I believed him after seeing that. However, I think a sucky amp clipped hard could still cause damage.
 

newsletter
  • RBHsound.com
  • BlueJeansCable.com
  • SVS Sound Subwoofers
  • Experience the Martin Logan Montis
Top