Marty, you owe the audiophile community an explanation. I have heard systems with subs, I have heard great bass and slam from other speakers. But your speed, slam, and jump - that jump, and bss control, is ten fold better than what a speaker can achieve on its own. Also there is a rise that happens on orchestral crescendoes, where I can see the music rising. I can see a drummer bang away in your system without overloading the room in a circular radius, as if he has the drums set up in a circle rather than in a plane, and is not holding back for fear of making the owner reach for the volume remote.
Can you, in the interest of audiophilia, experiment with the variables to isolate them as far as possible?
1. Room - How much of that signature on slam, speed, jump, and that rise, do you see in Russ' system which has Spectrals on JL subs
2. How much of that did you have with the VTL Siegfrieds before getting in the Spectrals
3. Without the TacT curve, but with that CR1, what has changed. I can see other benefits to taking the room correction out, but in relation to the above points?
4. Would that jump still stay if you brought the subs closer to the towers? Does it have anything to do with the distance? I did notice some jump when I once change the MBL amps to Spectrals on an MBL, but lower magnitude
I can see that it is a combination of things, but would be good to breakdown factors
Ked,
I don’t know if I will be able to address your query satisfactorily, but I’ll try my best. To begin, one good reason I’m not sure I can provide a completely satisfactory response to your query is rather obvious; namely, I’m not of the exact answers myself!
You’ve kindly referred to one aspect of my system in particular that you find compelling, which is that of “speed, slam and jump”. You also refer to bass control and the failure of the room to overload with orchestral crescendos, much as you’d hear in a good hall. Although these are related, I think they are probably due to different things. The control of the dynamics and failure to overload is probably more a function of the room than anything else. It’s a large room (25 x 35 x 14 =12250 cu ft or about 350 cu meters) that is fairly well damped but not excessively so. In addition, buried behind the fabric of the ceiling alcove (see 2nd pic of the OP) are Helmholtz bass resonators in each “corner” of the oval that probably account for the good bass control you’ve noted. I think that part of your query is therefore the most easily explained.
Now as far as the “speed, slam, jump”, I think there are several factors taken together that might help us understand that particular aspect of the system’s performance. The electronics certainly have a good part to do with that. I’m fairly convinced the Spectral 400 amps contribute mightily here because as you rightly assumed, that characteristic was not there to nearly the same degree with the VTL Siefrieds driving the Pipedream towers. If we consider that I crossover the Pipedream towers to the JL Gotham subs at around 82 Hz, and “speed, slam, jump” was not there in spades with the VTLs but is with the Spectral, this suggests that attribute is derived mainly from reproduction of the midbass and upper bass and not the deep bass which goes mainly through the Gothams. However, the deep bass certainly contributes in part, so I have to give credit to the VTL 7.5III preamp here as well for both its deep bass as well as mid bass performance. Although the VTL has a tube front end, it has a MOSFET output stage that can drive the crap out of anything over any interconnect distance by delivering gobs of current with a low output impedance.
I’ll also share with you at least one I thing that I believe has nothing to do with the “speed, slam, jump” factor you noted and that is power cables. I spent a year going down that rabbit hole and my results are posted here. (post 169)
http://www.whatsbestforum.com/showt...ce-other-than-potentially-reduce-noise/page17. In fact, the modestly priced PCs that I am currently using do every bit as fine a job in this department as my previous cables that looked like tree trunks and were priced more like a small car.
At this point, the relative contribution of two additional key factors need to be mentioned. The first, is the issue of time arrival at the listening position between the sound coming from the subs and those of the mains. There is no question this contributes to “speed, slam and jump”. The second is the relative smoothness of the frequency response from the low bass up through the critical midrange. Let’s talk about time alignment (impulse response) first. This has been discussed at length in some of my other posts; most recently in my comments as it pertains to using DSP correction for timing and crossover function (i.e TacT 2.2 XP) as opposed to an all analog approach using the JL Audio CR-1 crossover. That thread is here:
http://www.whatsbestforum.com/showt...L-Audio-CR-1-analog-vs-TacT-digital-crossover
Not to repeat my thoughts in detail, but the bottom line is this- DSP offers something that no analog crossover can accomplish which is the ability to have the wave fronts from the subs and the mains arrive at the listener position at the same time (if and only if the subs are placed behind the mains) by retarding the timing to the mains by a small increment (i.e. 4-8 msec depending on subwoofer location if placed behind the mains). DSP also allows for a more precise frequency response and careful tuning of the system’s bass frequencies to a level of precision that is to be envied, but may require a great investment in time to achieve. More on that in a minute. That said, what the analog CR-1 crossover delivers is a more transparent and less colored sonic palette most notable in the upper midrange and top end that allows for a easier re-creation of the “air” of the orchestra, or as I have called it, the orchestra’s “penumbra” (roughly translated: an area that lies on the edge of something; a fringe; related to, connected to, and implied by, the existence of something else that is necessary for the second thing to be full and complete in its essential aspect). Bottom line, that’s some fancy bullshit way of saying I like the top end of my system better with the CR-1 crossover than with the TacT.
So now let me try to answer the question Ked is getting at- if I think the TacT was so critical to time alignment between the subs and the mains, and if that contributes in a major way to “speed, slam, jump”, what happened to that precious attribute when I substituted the CR-1 for the TacT? Did my system's “get up and go” simply “got up and went”? Surprisingly, for the most part, no! Conversely, is it as absolutely spot on as it is with the TacT? Well, no to that as well. However, this is the key- are the benefits worth the liabilities? Did I gain more than I lost by going from a DSP to an analog crossover?
After a few months of listening, I think the answer is a hearty yes. First, its hard to ignore the beautiful benefits of going all analog from the midrange on up, especially when using a turntable. (Yes, I can hear all my good analog LP die hard friends now: ”OK, so he’s not crazy after all!). But here’s the real shocker. I have had some wonderful conversations on this very issue with JL Audio’s main technical engineer, Barry Ober, who admits that
ideally, it would be great if we had a way to retard the timing of the mains to match the subs for perfect time alignment between the two, but concedes that with careful use of the phase control and proper set up of subs, the modest timing error we are talking about would hardly be missed at all
by most listeners. He pretty much came right out and said that you’d have to be essentially nuts to even notice the error at all. To which I proudly say:
finally, someone understands me!!
But let’s get back to Ked’s inquiry, as there is one final item to be discussed. I may lament my loss of absolutely perfect time alignment between the subs and the mains with the CR-1 crossover, but as Barry Ober said, I don’t think most people would really notice any significant loss of “speed, slam’ and jump” at all in my current system. However what I do notice, and what I don’t think requires golden ears to hear, is that simply put, the overall frequency response is just not as smooth as when I could tweak it very precisely with DSP. And so, in order to get back some of what I have lost, I recently sold my Gotham subs and have the Gotham v2’s on order which are due to arrive shortly. What the Gotham v2’s employ is a digital automated EQ system for the woofers that can provide a much flatter response than was possible the original Gothams. Whereas the original Gothams allowed one to dial out the main room resonance frequency, the V2’s allow for a multipoint frequency adjustment that I think will be far closer to what I was able to achieve by using the TacT in conjunction with the original Gotham subs. We shall see. If the changes I anticipate with the Gotham v2’s combined with the level of “speed, slam and jump” I currently have using the CR-1 crossover offer an overall improvement from what I am experiencing now, I’m sure the smile on my face will be a good one.
Ked, your world tour in search of Audio Nirvana is now legendary and I understand you have some super systems lined up for your next leg of the journey. However, you know you are always welcome back to see if the proof is in the pudding.
Marty
