Statements + XPA-2 = not enough power?

[gromit]

I built a pair of the Statements about two years ago. I was powering them with a Yamaha receiver and last year upgraded to an Emotiva Fusion 8100. I knew I wasn't giving them enough power but would upgrade in the future.
A few weeks back, I hooked up some spare speakers to complete 5.1 and watched Interstellar. A few times during the movie the speakers would make a large pop or crack type sound. Scared the hell out of everyone. I during the vol down and decided it was time to get an CPA-2 for the statements.

I installed the new amp and could hear the difference easily. The bad had more punch and less boom. Last night a friend and I were listening to music and the Statements made the same pop/crack sound when the volume was up rather loudly. I did not expect this since I thought the 400 or so watts a channel would be more than enough.

Today I did some tests where I used a tube preamp instead of the fusion to make sure the problem wasn't with the receiver. I used my SPL meter and played Hold On be Alabama Shakes. As soon as the DB go beyond 100, the pop would surface.
I have a large room 20x20 and the speakers are 12' away from the seating. I decided to try one last thing set the XPA-2 in monoblock mode on one of the speakers and got the same result. If there is a peak over 100db, I'll get the pop crack sound.
The meters on the amp are near full and I've seen the red led flick on for a split second before.

Have I reached the loudest the Statements can go or the most the amp can push? Now I'm always nervous about the volume level and that's why I got a 1000watt amp, to be carefree with the volume.

[5th element]

Loud pops and cracks that scare the hell out of everyone are usually the result of the voice coil in bass units being slammed into the backplate of the drive unit. This isn't the result of a lack of power it's the drivers running out of excursion. Very low bass in ported systems will do this rather well as the cabinet and port offer very little control vs cone excursion below the tuning frequency.

A high pass filter and subwoofer are the only answer if you want to keep your extension. The other option is to plug the ports but that will limit how low the speakers will go.

[gromit]

I will try to set the receiver to cut off freq below 30 (that's its lowest setting) and see if that helps.

[JonMarsh]

Yeah, I'm with Matt on this one- I think you're hitting the excursion limits of the Statements- probably if you check Kurt's site, you can get some specific information on the tuning and the limits. But frankly, I think you also may overall be pushing the combined excursion and SPL limits- they're nice speakers, but 400W is a lot of juice for a double 8" system with moderate throw woofers.

[JonMarsh]

I checked Curt's site- I thought he might have a Unibox analysis for the SPL low frequency capability, but that's not the case. From the impedance curve posted, I can see the box tuning is in the mid 20's, so a high pass at 30 Hz is quite advisable. HT effects will often have significant power to 20Hz and less- some movies have been documented to go down to below 10Hz years ago- this is fine for a big sub with the right design, but NOT for a dialogue 8" system like this. Get a sub, and high pass these speakers at 60 or 70 Hz if you want those kinds of SPL, especially with movie effects.

[jwanck11]

I HPF my Statements at 60Hz.

In music, very few tones - other than organs and selections purposefully accentuating deep bass (pretty rare) are going to press that barrier. This is why I have a very musical sub - to deal with the long waves of extremely low notes when I want to hear pipe organ recitals. That said, my sub does not really come into play with music. For movies, the sub takes over and supplies the boom needed, as it is designed for. Thus, the statements HT system has a wonderful dynamic range for both music and HT with a proper bass solution - you get extraordinary clarity with presence of the mids and "close bass" not found in many designs as well as flexibility of an enveloping HT solution with a good subwoofer set up.

[gromit]

Found out the lowest the Preamp can cutoff is 40Hz. Jwanck11, what sub do you have? I really love listening to music on these and the idea of cutting off anything to them makes me sad. I listen to all types of music so I guess electronic music could abuse them in those low frequencies. I was just surprised that Alabama Shakes cause this since their rock. I guess I could listen at quieter levels and enable the 40Hz cutoff when I'm watching movies. I already planned on building a statement center, now I guess a sub is on that list.

[kevinm]

Do oh have enhanced bass on? I
This setting sends the LFE content to the mains as well as the sub. I accidentally had this on a few years back and it caused the popping you're talking about. At the time I was powering with an XPA-5

[tktran]

100dB at the listening position (12ft)?
That's more than 110dB @ 1m!

The Dayton RS-225 is a great woofer. But even the very best 8" woofer
is not going to manage 110dB at 40hz, let alone 20Hz, without severe distortion.

The sound you are getting are the woofer cones traveling beyond their limits
(Excursion limited SPL). At bass frequencies (<~100Hz) the maximum attainable
loudness level is not related to how much power (thermal power handling) but
but how far the cones can travel.

Eg. http://ocw.mit.edu/high-school/engin...box_vented.pdf

Getting a bigger power amp is not the solution. I agree the use of a high pass filter isn't ideal. A more elegant solution is a frequency based SPL limiter (DSP type).

Your only other solution is turning it down.

[gromit]

I do not have enhanced bass on. I guess I'm just playing it too loud.

[Paul K.]

I also sit 12 feet from my main speakers where I listen to only music and mostly classical. The average SPL at my ears is typically 80 dB or so. I cannot imagine anyone listening at 100 dB SPL on the average 8O unless their hearing is already shot from abuse. Turn it down IOW.
Paul

[kevinm]

I do not have enhanced bass on. I guess I'm just playing it too loud.

Could totally be the case.

What else is in your setup? What volume setting on your processor were you at? Are you using a sub?

When you say 100db, is that measured with a decibel meter/mic?

[gromit]

MacPro lossless iTunes over optical 96k 24bit ->
Emotiva Fusion 8100 as preamp set to mid 70's -> Emotiva XPA-2 -> Statements
No sub and I have the RadioShack digital SPL Meter.
I just wanted to make sure something wasn't wrong with my speakers or amp. Sounds like I just need to mellow out with the volume. If I keep it under 70 on the volume, I think I'll be safe. What can I say, sometimes I like my music loud.

[5th element]

Big spaces need big speakers to reach party levels. There's a reason pro sound exists! But all jokes aside there are limitations to what a pair of 8" drivers per side can do. The RS225s are very capable for what they are but it sounds like you enjoy party levels with bass heavy material from time to time, but then again so do most people! This is what subs and high passes are for. My listening room is only ~3x4 meters. Yeah that's right, ~9x12 feet, we have small rooms here in the UK, but still I have 4 sealed 10" sub woofers in that room. Is that needed most of the time? No. But it is required for 20Hz extension on HT stuff when I decide to crank it, no way around that.

If you really want to check that over excursion is what's causing the problems then take the grilles off of your statements, put some music on and go stand next to them (maybe with ear protection on) and watch the woofers. When you've got it cranked are the cones of the RS225s flapping about like crazy? Remember here that the linear region of these drivers is only 8mm forwards and 8mm backwards. That's 16mm total. In bass driver terms this is actually quite a lot, but visually it may not seem that impressive. Now the RS225s should go comfortably beyond this before a 'crack' occurs, but in some drivers this might only be 12mm backwards from the xmax of 8mm.

I'll never forget the first time I heard a driver crash into the backplate though. This was when I was around 15 or so and I had it cranked on a pair of Mission loudspeakers with a HM170Z0 mid/bass variant from Audax and I jumped out of my seat!

[Jim Holtz]

Lots of great feedback that I fully agree with. "Most" music has very little if any content below 40 Hz. but pipe organ and techno isn't most. If the recording has lots of bass below 40 Hz. its into HT territory particularly at high volumes. We've always used the rule of thumb that the Statements were safe to about 115 db maximum in a normal sized room with most music. That is pushing the limits and is above the manufacture rating of linear response.

So, with that thought in mind, I've attached a Unibox excursion/frequency graph that can be used as a guide.

BTW, I've never bottomed my Statements. I don't use a sub for music but do have (2) 15" subs I use for home theater. My normal listening volume is about 80-85 db.

Here you go....

Jim

[gromit]

Thanks everybody for helping me figure this out. Like I said in the beginning, I wanted to make sure something wasn't wrong with my amps or speakers and I'm comfortable knowing I just had the volume too loud. Now I need to build a nice musical sub (or two) AND a Statement center channel. FYI, The Interstellar bluray will seriously push your speakers in the low frequencies. That's what's triggered all of this and when I googled and saw the movie referred to as "a speaker and sub killer," I really got nervous.

[jwanck11]

I have a 15" Martin Logan, which is a good musical sub for being a bit small and non-ported. I use it to accentuate low frequencies. It is very pleasing when it thumps about and by no means is it "sloppy" or disconnected from the rest of the running frequencies.

There are loads of excellent designs and build threads for subs at avsforum. I'd suggest any good 15" musical sub either ported or non ported will deliver significant low frequency output that compliments the statements at loud volume very well. I am about to start another build thread...... or two. One of which will be for a sub design called the "martysub." I am going to build 2 ported boxes that will have an 18" Dayton umax drivers in each. This will almost solely be for HT usage. Yes, I am kissing loud organ music (I do not listed to techno) goodbye, though my Statements are all I want in terms of volume in my 12X16 open rear walled room. I am more into clarity and presence of a soundstage that the Statements deliver with aplomb, that's just my preference. In HT, I would not want to rely on anything other than subs to shake the house when that's what is called for. Having them in mains gives up what I want most and therefore would be a waste.

Good luck choosing a sub and by all means, if you build one, start a thread!!

Oh, and the statements center channel is fantastic. I am picking up sounds behind sounds now that my center is nicely run in.

[IslandHydro]

I've bottomed out woofers in the past, not recently. Be forewarned that you can damage the voice coils by doing this (don't ask how i know ops. Essentially you'll deform the end of the voice coil former, and it will then rub on the pole piece (I think). You can test to see if this has happened by gently pushing in on the woofer cone, make sure you apply force symmetrically or you'll cause rubbing that otherwise wouldn't be there. If you press symmetrically, and hear any kind of scraping noise, the voice coil is shot. There will also be intermittent distortion (buzzing) from drivers with warped / deformed voice coils.

[TEK]

If you are gong for sub and are interested in high quality sound I would recommend several sub's instead of just one.
You could download REW, it has a room-simulator (don't need any measuring equipment to use that part of REW) that will show you a simulation of the quency response with different numbers of subs and different placements of the sub's in your room.

I have 3 subs. 2 15" on each side in the front of the room and a 18" in the back of the room. My 15" is two Rythmic audio servo based sub's. Very accurate bass. The 18" is a Aurasound DIY sub. Very deep bass.
All subs are closed box DIY designs. Having several sub causes the sub to even out frequency tops and bottoms caused by room modes and gives a better result.

[kevinm]

If you are gong for sub and are interested in high quality sound I would recommend several sub's instead of just one.

Or you could just put (4) 18in driver directly under your couch. Then your basss is so loud you can't hear anything else!

Kidding of course. This is great advice.

[5th element]

Or you could just put (4) 18in driver directly under your couch. Then your basss is so loud you can't hear anything else!

Lol Kevin.