Stealth 8 Specs -> Response curve plots PDF link incorrect?

[bcbigb]

Hey guys, long time lurker with a question for you.

I'm having a hard time getting ahold of Emotiva proper (probably busy with the Xmas season and this holiday sale), but I'm seeing something that doesn't make any sense. The Stealth 8 specs PDF shows the dropoff at ~45hz while it says it's flat to ~30hz. I've seen it glossed over in other threads like people are just accepting this complete inconsistency and aren't even wondering why it doesn't make sense. Maybe you can help me to confirm that the Stealth 8s are indeed flat to 30hz as I don't want to miss out on this holiday sale. Here's a snippet of the e-mail I sent to Emotiva sales a couple of days ago with links etc:


"I can’t reconcile the spec sheet linked to on the Stealth 8 page with the specs listed. Namely, it says it’ll be practically flat (±1.75db) to -30db, but the SPL chart clearly shows the big dropoff start to happen at around 45hz or so, which seems like the PDF was an accidentally-renamed/uploaded copy of the one for the Airmotiv 6s, which drops off at 43hz."

[Axis]

Not being sarcastic in any way. I am just curious. Is there material that you need to reproduce down to 30hz like for professionally mixing? These are marketed as professional monitors.

[bcbigb]

Yeah. I will use these in my home studio to test against my current monitors, a pair of Dynaudio BM15As, which are very solid performers, but I've been hankering for a little more low-end without a sub (acoustically a sub is very difficult to control in this space, especially without good bass damping at the moment, long story) and I'm dying to get a proper ribbon-tweeter to A-B with the Dynaudios, plus I've never heard any of the Emotiva speakers and before purchasing just want to take care of this niggling detail to ensure there isn't something I'm missing (or namely, something the Stealth 8 is missing). I'm 99% sure this is a mistake, assuming the Stealth 8's listed specs are right, because they make sense relative to the AirMotive6s. I just want to get some quick acknowledgment or an independent test or verification that they go that low and I'll be ordering them right away.

[bcbigb]

Oh, and I'd like to see the proper plots for the Stealth 8, again assuming I'm right that it is a mistake, for all of the good gear-head reasons that we all like plots... :-)

[klinemj]

Your best bet is to call them.

That said, in your e-mail, it didn't appear you asked them a question. You merely made a statement. You might have had better luck asking a question...like "which is correct, the specs listed or what I see in the graph?" But, even then...calling is best.

Mark

[Axis]

I remember before Emotiva released the Stealth 8's Dan put them out the wild at many Pro and High-End shows and I would read comments on them in obscure forums and reviews of shows that I doubt anyone here even knew about. Everyone was just blown away by them. Dan had them hooked up to the Emotiva DC-1 DAC. The only thing I have heard negative on them which is probably just someone's opinion and or is true for any two way monitor with an 8" woofer, is the mid frequency gap between the drivers. I know I could not hear it.

[djreef]

I haven't heard that either.

DJ

[garbulky]

I wouldn't expect any speaker with a single 8 inch speaker get down to 30 hz in the way that a sub would. I think your expectation of 45 hz is accurate but also that it will produce substantial volume below that. Remember room gain helps.

[bcbigb]

Thanks guys. I do believe it'll hit that, even with only 8" behind it, as not only are there several other products out there that can do it, but, per Bob Carver, you can get lower with larger drivers (typical) or with longer-throw smaller drivers, and 8" isn't too small to hit 30hz without crying about it, plus IIRC these are ported which is responsible for some of that bass extension, so the driver isn't directly generating all of that out of the baffle. I realize there are other considerations with that, such as accuracy when one cone is expected to hit a particularly large range, esp. in a 2-way design, but I'll take my chances at the moment. My original question is just to verify the specs with Emotiva support, independent of what I'll do with them :-).

Mark: I'm going to take your advice and look over the original e-mail in its entirety, but I only posted a relevant snipped up here. I'm pretty sure I was more thorough in asking them to reconcile the differences for me in the original.

[klinemj]

I will say I have heard them at Emo HQ a few times, mostly paired with a DC-1 playing files from USB. They were spectacular in detail and punch.

Based on how they sounded, it would not surprise me if they reach 30 hz or close to it...and with authority.

Mark

[KeithL]

The frequency response of a speaker, especially the bass extension, will vary quite a bit depending on the room you measure it in and where you position it in the room.

It's also rather difficult to make accurate measurements of speakers for a variety of reasons. (In many speaker tests, in the fine print, you'll see that they actually measured the output of the woofer using one method, the tweeter a different way, and the output of the port a third way, then combined the various measurements into one curve. They do this because, depending on the room and your test equipment, the same method that gives you accurate tweeter and midrange measurements may be totally inaccurate for measuring the woofer and vice versa. Another solution is to take measurements in an anechoic chamber; however, to be honest, anechoic chambers are big and expensive to build, and anechoic measurements tend not to reflect performance in a real room very well anyway. They're great for designing, but not so great to tell how the speaker will perform in an actual room.)

In short, the printed (PDF) graphs were done using our AP test set, in one particular room, with the microphone relatively close to minimize room interactions, while the "specs" represent measurements taken in a more normal room. The graphs are better at showing things like overall smoothness, and how the graph doesn't zig-zag up and down wildly in the midrange like a lot of speakers, which is why the Stealth 8's sound so smooth; buy the spec'ed numbers are a more realistic example of the readings you'll get if you measure bass extension, with a tone generator, in a normal room, with the speakers mounted in more typical locations. (Bass output will vary considerably depending on the room, how far you're sitting from the speaker, and even things like the height of the stands you use, and the distances from the back and side walls... )