@mijostyn wrote:

I do not like Crown amps. I have had them twice and both times they were unsatisfactory.

I’ve previously used Crown’s Macro Tech class A/B series for subs duties for a short while, and found them to be very good amps (not only in the subs region, certainly with the 3600 model on down), but their built-in fans were noisy like angle grinders, and by now the Macro Tech’s also have quite a few years under their belt. The class H-based Crown K2 is another very good and popular subs amp, and moreover it’s passively cooled (but one needs to disable the auto standby function). I used the K2 over my subs for some years, as well as upper bass/lower mids duties, and it excels in the bottom octave in particular with good weight and control while lacking a bit of mid bass prowess.

A beast of a subs amp is the class TD-based Lab.gruppen FP6400, which I used for years with my subs as well as midbass section. Crazy powerful amp, though not as musically natural in the lower octaves compared to my current MC² Audio class A/B amps; finding a suitable subs amp isn’t only about having enough power (which is the easy part), but also and not least about what complements the audio range above the subs region. I find using essentially similar amps top to bottom to be very important for overall coherency and tonal imprinting - something few seem to be aware of and actually implement in their subs setup and considerations. Using a dedicated quality DSP (that acts as a digital XO for the mains as well) with a vast and intricate range of settings only adds to the advantages.

@audiokinesis wrote:

One of the reasons I use vented enclosures (tuned such that their response is the approximate inverse of typical room gain from boundary reinforcement) has to do with thermal power handling. A comparable sealed-box sub will theoretically need roughly three or four times as much power in the region of the port tuning frequency in order to have the same frequency response. Also, a port allows an exchange of air with the outside world, so you don’t get that "oven environment" that you do with a high power sealed box sub. In other words, imo there are arguably worthwhile thermal benefits from making a vented box approximate the frequency response of a very low-Q sealed box down to the port tuning frequency.

+1

Like ported boxes, tapped horns (contrary to sealed designs) also have excursion minima at the tune, but by comparison seem to be less marred by group delay effects. Being also they’re very efficient, certainly with a tune not much lower than 20-25Hz - in addition to having the driver’s backside exposed in free air at the mouth - makes them very resilient to thermal overheating.

@ditusa wrote:

Subwoofer bass myths, see here!

Mike

+1

@mijostyn wrote:

Funny you should mention the K2. They were the last Crown amps I will ever own. Their control over big sub drivers with high BL products was terrible. I think it was the back EMF that destroyed one of mine, the other went in the dumpster.

My context of experience with the K2 is having heard it driving different high efficiency, large subs (a pair of them in all cases) fitted with woofers with a BL factor in the 20-26Tm range, and no control issues here. Honestly I’ve never heard the K2 at the end of its ropes here either, nor the subs for that matter - even at bonkers SPL’s.

Your context of previous use with the K2's is obviously quite different, and to put things into perspective: using sealed subs with over 10dB’s lower sensitivity there’s a power requirement over 10 times as much, meaning - in theory - a 500/800W K2 would do with high eff. subs that a some 10kW amp should do with a low eff. subs equivalent. That is: the first scenario offers you both headroom and prodigious pressurization in a domestic environment; the latter would end up in smoke trying to achieve anything similar.

... So, you burn up a voice coil once in a while. I keep two drivers in reserve although I have yet to lose a dual voice coil Dayton yet, it is only a matter of time. Subwoofer drivers take a beating as it is leading to a high failure rate in any event.

...

@phusis Good article and no arguments from me. I cringe every time someone characterizes a subwoofer driver as being "fast"

I do not care so much about efficiency. I care most about accuracy and by a huge margin it is the enclosure that causes the most trouble, not the driver. The majority of enclosures are musical instruments.

I’m assuming the latter quote of yours is aimed at poster @ditusa, but I’ll have a go at it nonetheless.

From the above it follows that the driver is a potential issue of yours. Needing a couple of them in reserve due to expected woofer failure - that is, woofers used here that are by all accounts no slouches in themselves - is indicative of very high power output and occasionally using the subs close to or even beyond their capabilities, which again equates into steeply rising distortion levels. You may have won points with close to inert sealed subs cabs, but from my chair the drivers will bring that score into the negative again if working very hard.

I’m assuming though you have a winning combination at more "normal" listening levels.

@ditusa wrote:

In my opinion, not all Crown amps are created equal. The mother of all Crown amps is the Crown Studio Reference One, it’s the best sounding Crown amp, past and present and it’s class A B! You must run the Crown amp on a dedicated AC 120 Volt 30 Amp circuit minimum. 😎

+1

The Studio Ref. 1 and 2 are great sounding amps indeed. I almost bought the Ref. 2 some years ago, but have heard them regularly at friends’ places over the years. Rock solid, reliable amps, and it takes some heavy beating to spin up those fans. I never get to that (i.e.: spinning up the fans from their close to idle state) with my MC² Audio amps and efficient speakers, only the occasional flashing of the blue signal LED’s on the midbass and subs amps when watching movies, in which case it means they are using +10W.