In quest of budget reclocking

[PewterTA]

I think he meant, take the GF out first.

[Chris D]

... and then maybe laundry, depending on how much you're locking yourself up in your man-cave lately.

I'm guilty of it.

[JonMarsh]

I think he meant, take the GF out first.

Ah, so, desu! Dōmo arigatō gozai mashita!

Alles klar...

[wkhanna]

But Bill, we must maintain the hysterical, er, historical progression! And from much prior experience, I know roughly how well the DCD8 works, so verifying that in the current context is necessary to evaluate the Mutec. Now, I'll admit the Genesis is just an historical curiosity which I throw into the mix just to exercise my powers of curmudgeonly historical precedent... :W

Genesis Digital Lens


Whoa…….Talk about being ahead of the curve……..

Or possibly, just hindsight revealing someone was on to the issue before it was determined it was an issue.

And yes, of course we must always maintain hysterical…errr …. Heretical….errr ….highest priority on this cooperative endeavor & stand steadfast in the face of tyrannically imposed tithe of time put upon us by those who would attempt to divert our course & monopolize the passion within our souls to fulfill their own desires. I therefore amend my previous recommendation thusly to adequately satisfy cursory GF obligations by way of a quick trip to In-N-Out Burger.

BTW, you still working on training her to do your laundry?

[JonMarsh]

Genesis Digital Lens



BTW, you still working on training her to do your laundry?

:rofl: :rofl: :rofl: :rofl:

IBM systems engineers don't do any laundry other than their own!

And speaking of priorities, tomorrows is a hike with GF on the Hayward fault, something she researched earlier this week. So Saturday will be rather curtailed in the realm of audio productivity.

I just got back from a few minutes at a beer bash function at the company I'm embedded in the last few months. They have them every couple of weeks in the summer, I hear. This one I got to look at the new Mac Pro up close and handle the heatsink and PCB assemblies, and play with both an iPad Air and the unreleased Retina iPad Mini. Hmmm, I suppose that may have given away where I'm working these days- even have a vendor badge, so superficially I look like an employee. talk about conflicted... :roll:

[Finleyville]

Just remember: Fruit is a food and not a computer.



Although in your case it also supplies a paycheck.

[JonMarsh]

Well, I guess that means personally own 6 pieces of rather expensive aluminum fruit! :W

[PewterTA]

I can only imagine what that does to the digestive system.

[PewterTA]

Well I just gave Bill the Rubidium Clock (his) so that he can make sure the holes in the heat sink lineup. Next we need to get the PS... so if anyone happens to see a nice PS for our clocks (going to get one at the moment -- splitting the cost, then buy the second after testing).... please let us know.

Then of course we need something to re-clock the signal with, which will be another step. Slow process, but we are making progress.

Bill and I just need to win the Lottery and we'd be all set! ha ha!

[JonMarsh]

Bill and I just need to win the Lottery and we'd be all set! ha ha!

But are you buying tickets? I never do, so I don't have to worry about winning... :W

Not a productive weekend, except for getting Mac Pro stripped and equipped with new SSD boot drive and new HD's, and a fresh install of OSX Mavericks on the SSD after creating a bootable USB stick installer, to give to daughter's older partial quadriplegic cousin for Xmas... at least that is finished and ready for them to take up to Sacremento on Thanksgiving...

[jim1961]

Jon,

I think i have sold a friend on the NAD M51. Should get to hear it in the near future. Scott bought one as well (as you may already know).

NAD should consider giving you commissions

[JonMarsh]

Jon,

I think i have sold a friend on the NAD M51. Should get to hear it in the near future. Scott bought one as well (as you may already know).

NAD should consider giving you commissions

Only if they're all happy users that get one! So far, we are batting 1.0 on that... let me know what you think.

NAD isn't often the first thing people think of for fairly high end gear, but their Mastersound series is pretty dang good, and the other folks I've seen online that have done shoot outs with the M50 music server have been very surprised and pleased, too- someone there knows what they are doing, and I'd say listens closely as well as measuring.

If I can get Thanksgiving week off, I hope to get a lot of things sorted out at GF's, including getting the M50 hooked up into the system, and doing some comparisons/evaluation with the various re-clocker options.

[wkhanna]

Dear Maestro,

The PS is ordered (don’t panic Dan, I just picked up a used Omron S8VS-09024B 24VDC for $50).

Regarding the mounting of the heats sink to the LPFRS…….
….the heat sink is 1 inch longer than the oscillator case.

My question is: will it be acceptable to cut the heat sink (roughly 3”x4”) down match the size of the oscillator case (roughly 3”x3”)?

I am thinking about the final packaging of this assembly & if it can have a smaller overall foot print, the better.
I just don’t want to compromise the thermal dissipation requirements by making the heat sink too small.

Also, confirming the need for an SMA Coax to BNC cable for scope testing.
What type connector is required for hook-up to the DC8 & Mutec MC3?


Signed: BBIT (Baby Bagger in Training)

[JonMarsh]

My question is: will it be acceptable to cut the heat sink (roughly 3”x4”) down match the size of the oscillator case (roughly 3”x3”)?

I am thinking about the final packaging of this assembly & if it can have a smaller overall foot print, the better.
I just don’t want to compromise the thermal dissipation requirements by making the heat sink too small.

Also, confirming the need for an SMA Coax to BNC cable for scope testing.
What type connector is required for hook-up to the DC8 & Mutec MC3?

Well, you could cut down that nice heatsink, but I wouldn't- that clock module dissipates a bit of power and we need a good Rth to ambient- plus, cutting that nice anodized heatsink would be a gosh darn shame... :W

You will need an SMA to BNC cable for two reasons, my Padawan learner-

1. This is the correct configuration to connect the clock unit to a scope input, which is BNC.
2. This is the correct configuration to connect the clock output to the WCLOCK input on a Mutec or any other similar unit... do your homework, study the documents- you will have more confidence if you don't just rely on Dan as your tech guru.

[wkhanna]

- that clock module dissipates a bit of power and we need a good Rth to ambient- plus, cutting that nice anodized heatsink would be a gosh darn shame... :W

I suspected as much, & will refrain from marring the gorgeous HS :W with my milling machine & instead allow 1/2" overhang on each end.

- ... do your homework, study the documents- you will have more confidence if you don't just rely on Dan as your tech guru.

With all due respect to Dan, not so much him as you for some specific aspects of this project.:B

But as, always, wise & sage advice........time to put the 'Y' back in 'DIY'. :T

[PewterTA]

I like learning as much as Bill... I probably would've asked the same question on to which connections I needed on the cable just so I didn't buy what I "thought" it was... and then ended up with a cable I didn't need. Might as well ask while we have Jon's ear for 3.847345624252943 seconds (yeah this clock works good)...

My closet is full of cables that I don't need anymore (not that they were bought in error, just over time one seems to have cables drawn to them from all over the place. No need to purposely add.

Bill... I want a better power supply.... $50... that's too cheap, it won't work good! LOL.

Has anyone ordered from ThorLabs for cables? Just curious if those are decent enough cables and will work.

Question, do cables matter (on the clock side of things)??? hmmmm....

[wkhanna]

Stayed at work late today in order to mount the HS.

Thought about using the 72" Doosan 5 axis vertical mill to drill the holes, but John was working on some bridge bearings (the bearings that go between the road deck & supports for highways).

So I decided to go "Old School" with a good'ol manual Bridgeport mill.
















I will put some Locktite on the screws when I mount the thermal pad between the clock module & HS tomorrow.

[PewterTA]

Awesome!!!! Powersupply and a something to regenerate with and we are ready to start playing!!! Hee hee!

[wkhanna]

The power supply with be here today.

I have to work on Saturday, but will try to get the PS wired up (110 AC supply & the 24 VDC to the clock) & everything temporarily mounted to a base of some dielectric material to help prevent any shocking test results.

I will get cable ordered by this weekend & we may be able to run the scope test within a week or so.

[JonMarsh]

I like learning as much as Bill... I probably would've asked the same question on to which connections I needed on the cable just so I didn't buy what I "thought" it was... and then ended up with a cable I didn't need. Might as well ask while we have Jon's ear for 3.847345624252943 seconds (yeah this clock works good)...

My closet is full of cables that I don't need anymore (not that they were bought in error, just over time one seems to have cables drawn to them from all over the place. No need to purposely add.

Bill... I want a better power supply.... $50... that's too cheap, it won't work good! LOL.

Has anyone ordered from ThorLabs for cables? Just curious if those are decent enough cables and will work.

Question, do cables matter (on the clock side of things)??? hmmmm....

What I bought was this, from eBay:




Here's a link to the item - would recommend this source - don't need to worry about HF reflections, as you're pumping a sine wave around, not a square wave.

http://www.ebay.com/itm/10ft-BNC-Male-Plug-to-SMA-Male-RG58C-U-RF-Coaxial-Cable-CablesOnline-RF-BS10-/390513235143?pt=US_Radio_Comm_Coaxial_Cables_Conne ctors&hash=item5aec6714c7

This is the "one" cable we've used in all of our experiments in Munich and in the USA with DCD8.

I believe Bill linked the same type OMRON power supply as I bought, he just found a better price... no arguing with that, as long as it works. If you want to get all OCD, go find a linear supply in the same voltage and current range; be prepared to pay a lot, lot more. Probably to no worthwhile effect, as the Rubidium clock has filters and internal regulators.

[JonMarsh]

Yeah, well, your mill is just a skosh larger than my drill press, for certain! But I can carry my drill press around in the back of my Honda Element OR my NSX, and store it in a pretty small space! That Bridgeport doesn't exactly look portable... won't fit in either of my cars! :W But it looks like it will get the job done. :T

But hey, we do use some of the same brands of screw drivers!



I don't want to jinx things, but from emails I've seen early this morning, it's looking more and more like I will get my vacation time next week, which is good both for evaluations on this with the Mutec and work on the Isiris. :T

[wkhanna]

EDIT: I posted this before i saw that The Meastro already provide us with the info......

But hey, I know a lot more about coax than I did previously.



Found an interesting tidbit at this wiki link:

RG-62 is a 93 Ω coaxial cable originally used in mainframe computer networks in the 1970s and early 1980s (it was the cable used to connect IBM 3270 terminals to IBM 3274/3174 terminal cluster controllers). Later, some manufacturers of LAN equipment, such as Datapoint for ARCNET, adopted RG-62 as their coaxial cable standard. The cable has the lowest capacitance per unit-length when compared to other coaxial cables of similar size. Capacitance is the enemy of square-wave data transmission (in particular, it slows down edge transitions), and this is a much more important factor for baseband digital data transmission than power handling or attenuation.


I like the RG types that meet Nuclear Instrumentation Module (NIM) standard which defines mechanical and electrical specifications for electronics modules used in experimental particle and nuclear physics. But I doubt any of that is relevant to our application.

From what I gather, low capacitance is a good thing for our need (even though I think we are generating an analog sine wave & not a square wave or digital) along with good shielding.

Possible contenders span a broad range of price:

RG No Clue Cheap


RG 316 Not Quite as Cheap


RG Got No Clue & Not so Cheap & but it says "Frequency Range: DC - 4.0 GHz"


RG214 Holy Crap!

[wkhanna]

OK, so RG58 with a stranded core is all we needed.

I certainly do not mean to contradict The Maestro, but would a similar cable of shorter length be acceptable?

Link #1


Link #2


Edit:

Never mind.
I went ahead & ordered the recommended 10ft cable (free shipping plus an added $1 to the Veteran's fund), this way are all comparing apples to apples.

[JonMarsh]

Both of those linked would work, I never tried Amazon, though I do buy a lot of weird stuff from them; nothing wrong with that price!

But you know, one thing I seem to always run into, is that if I buy the shortest cable I think I can initially get away with, I usually find out later that I wish I had a longer one... this way, the rubidium clock can be tucked away somewhere more convenient, perhaps for the power supply connection, or for ventilation for thermals, for example.

Don't forget, you should warm up the clock for10-15 minutes before listening. :W

[wkhanna]

.....you should warm up the clock for10-15 minutes before listening. :W

Thank you for the reminder, as the same will be true when we o-scope test, too.

[wkhanna]

PS is in hand.........

[JonMarsh]

Better than in the bush... :W

[PewterTA]

Well now we have to get this all figured out and Jon you're going to have to step things up because Santa is bring me a NAD M51 for Christmas it looks like...

Now I'll probably end up having to offload my CA 840c since I don't think I'll need both.

Looks like Bill and I will have to find the last missing piece in order for us to really start testing thing.

[JonMarsh]

Well now we have to get this all figured out and Jon you're going to have to step things up because Santa is bring me a NAD M51 for Christmas it looks like...

Now I'll probably end up having to offload my CA 840c since I don't think I'll need both.

Looks like Bill and I will have to find the last missing piece in order for us to really start testing thing.

All of that sounds like good news, to me! Was setup for speaker testing yesterday, though, but found an issue with the Preamp I was using to drive the Aragon power amp with the test signal. Hope to have that sorted out today, as well as get some progress today or tomorrow setting up the re-clockers to listen to.

[PewterTA]

Wooo Hooo! Good luck!!! I'm trying to be good and not tell the guy to just take out the full amount of the NAD and send it to me (agreed to split the payment to help since the holidays are here and I didn't really plan for getting this... So I'm trying to force myself to not have him just charge the full thing and send it out on Monday. LOL.

Good things or great things come to those who wait right?!!?

Can't wait to hear your findings!!

[JonMarsh]

Well, with the DIY approach you always have to be patient and looking at the long term, because slow work DOES take time!

Yesterday I found a root cause issue without of the big speakers because I hadn't had time to measure both of them prior to the Northern CA DIY meet back in April, and had moved them direct to GF's. Well I did finally get the measurement setup back up and running with the so called music player iMac, and my Ayre preamp, and got things fully tested and sorted out with the new LF and HF crossover builds. But ran out of time to get to the clock hardware, so that's going home with me this morning, hopefully to make some progress while also doing laundry and other chores to get ready for the work week.

At least that's come along pretty well- this is the in room response with a long measurement window (150ms) with the mic at the normal listening position- no hunting around for an "optimum take".



I'm going to need to see if I can tweak the room position to smooth out the bottom end, but the basics are in line and they sound great in the dining room which hangs off the other end of the family room. And note, that measurement is going out to 50 kHz. The JDT-1024 have a slight bump on axis above 10 kHz; are actually flatter at 30 degrees off axis. Makes for a nice power response profile.

[jim1961]

Well, with the DIY approach you always have to be patient and looking at the long term, because slow work DOES take time!

Yesterday I found a root cause issue without of the big speakers because I hadn't had time to measure both of them prior to the Northern CA DIY meet back in April, and had moved them direct to GF's. Well I did finally get the measurement setup back up and running with the so called music player iMac, and my Ayre preamp, and got things fully tested and sorted out with the new LF and HF crossover builds. But ran out of time to get to the clock hardware, so that's going home with me this morning, hopefully to make some progress while also doing laundry and other chores to get ready for the work week.

At least that's come along pretty well- this is the in room response with a long measurement window (150ms) with the mic at the normal listening position- no hunting around for an "optimum take".



I'm going to need to see if I can tweak the room position to smooth out the bottom end, but the basics are in line and they sound great in the dining room which hangs off the other end of the family room. And note, that measurement is going out to 50 kHz. The JDT-1024 have a slight bump on axis above 10 kHz; are actually flatter at 30 degrees off axis. Makes for a nice power response profile.

Ruler nice down to about 140hz. The +6db @ 100hz and -11db at 40hz need some work obviously though. How does it look @ 1/24th oct smoothing?

What kind of house curve are you aiming for on the bottom end?

[JonMarsh]

Here's the same measurement but only with 1/48th octave smoothing.




Pretty much what I'd expect, given no room treatments per se, just somewhat careful setup. I'm hoping to talk GF into letting me put up some floating absorbers between the roof beams, and a few other things, but that may be limited.

As regards the house curve, I hope to knock down the 100 Hz region bump and smooth out the lower bass; using boundary lift to fill in for the slow sealed roll off as described in the design study thread. Heck, I'll probably even get a genuine build thread put up over the holidays if I can find the time...

I've toyed with the idea of building some simple passive shelving equalizer boxes to go between the preamp output cables and the power amp input connectors; nothing more than 4-6 dB lift in the very low end.

This is what the filtered near field response looked like with the Mk1 version of the crossover.

Boundary reinforcement in principle gives us back 6 dB or more around 30 Hz, but I figure another 4-6 wouldn't hurt- another experiment to consider over the holiday break.

[jim1961]

Here's the same measurement but only with 1/48th octave smoothing.



Pretty much what I'd expect, given no room treatments per se, just somewhat careful setup. I'm hoping to talk GF into letting me put up some floating absorbers between the roof beams, and a few other things, but that may be limited.

As regards the house curve, I hope to knock down the 100 Hz region bump and smooth out the lower bass; using boundary lift to fill in for the slow sealed roll off as described in the design study thread. Heck, I'll probably even get a genuine build thread put up over the holidays if I can find the time...

I've toyed with the idea of building some simple passive shelving equalizer boxes to go between the preamp output cables and the power amp input connectors; nothing more than 4-6 dB lift in the very low end.

This is what the filtered near field response looked like with the Mk1 version of the crossover.

Boundary reinforcement in principle gives us back 6 dB or more around 30 Hz, but I figure another 4-6 wouldn't hurt- another experiment to consider over the holiday break.

What I meant here, is in a perfect world, how much (if any) do you like the bass elevated. By how much and over what frequencies?



Something like this perhaps?

[JonMarsh]

Right, THAT kind of house curve.

That's something I'm not really decided on- because of how many records are mastered, and other limitations of playback equipment, a lot of folks DO go for something like what you drew in. In fact, the way we implemented MEB46's Isis clones, they'll have a bit of a house curve built in, because as designed in larger enclosures and ported, they will usually wind up bass heavy with boundary reinforcement, especially with close placement to the wall.



This is the quasi anechoic calculated response, not considering boundary effects.


This will result in a "house curve" that many folks prefer (slightly zaftig, shall we say?) where as I'm a bit more of a fan of a leaner presentation, critically damped, and if needed use judicious shelving eq without any transient ringing to bring things in line.

So doing a first cut estimation of boundary distances and target box functions, this is what I came up with:



IF the boundaries are not stiff and fairly high "Q" then the boundary lift will not be as great.

My next investigation is to get out my Cardas room setup PDF and experiment with a different listening layout, with the idea for GF that this is just an experiment to see how things might tweak out. (it will undoubtedly require moving the sofa back a bit... :W )

I haven't been too concerned about dialing in this aspect until I got the new LF crossovers tested (in system response seems to be working quite well) and build the new Mid crossovers and test those. If it warms up at all, I'll take one speaker out doors and do an outdoor test just sitting on the patio, to see how things are without any other adjacent surfaces. This could happen next weekend, given the weather forecast, though there may be so much going on I have to put it off.

[PewterTA]

On a side note... Bill showed me the clock with the head sink, the power supply and the cables all hooked up. Looks great! Now to just take it and go get it tested, we're trying to find some time (maybe this weekend possibly).

It's getting closer and so it my M51 which just leaves one piece remaining for Bill and I to get. Then let the fun begin!!!

[jim1961]

Jon, I take it your working with full range speakers, not a satellite (or full range XO) / sub combo?

Just to make a obvious point, its really easy to achieve a heightened 20-80hz shelf when a sub is running at 20-80hz

[JonMarsh]

Jon, I take it your working with full range speakers, not a satellite (or full range XO) / sub combo?

Just to make a obvious point, its really easy to achieve a heightened 20-80hz shelf when a sub is running at 20-80hz

Oh yeah... it sure is! The speaker I'm working with hear is the Isiris full range, with dual NS12s- now your mention there does bring up another point, is that adding in a big sealed sub in the 20-60Hz range (say, with the boxes either near by or a little farther away in the corners (with a lower upper crossover point) could give me some additional flexibility for "picking up" the house curve, and that's something I have been thinking about. I even have a prototype of sorts for doing that, with the sealed sub I put together for GF's HT (with Dayton Audio UM12-22). So, possibly we'll take the fill in mode- have to wait and see.

[JonMarsh]

On a side note... Bill showed me the clock with the head sink, the power supply and the cables all hooked up. Looks great! Now to just take it and go get it tested, we're trying to find some time (maybe this weekend possibly).

It's getting closer and so it my M51 which just leaves one piece remaining for Bill and I to get. Then let the fun begin!!!

THIS Sunday I remembered to bring the tools and parts for that back home from GF's, so this coming Saturday I should be able to mount my heatsink and be ready to start testing. Hmmm, I probably better get started on this whole Christmas shopping thing, too.... if I can confirm the operation of the Mutec this next weekend, and how to set it up, I'll ship it out to you guys to try out over the holidays. Otherwise it will likely go out the following weekend and be there just after Xmas.

[jim1961]

Oh yeah... it sure is! The speaker I'm working with hear is the Isiris full range, with dual NS12s- now your mention there does bring up another point, is that adding in a big sealed sub in the 20-60Hz range (say, with the boxes either near by or a little farther away in the corners (with a lower upper crossover point) could give me some additional flexibility for "picking up" the house curve, and that's something I have been thinking about. I even have a prototype of sorts for doing that, with the sealed sub I put together for GF's HT (with Dayton Audio UM12-22). So, possibly we'll take the fill in mode- have to wait and see.

Looked up that driver:

http://www.parts-express.com/dayton-audio-um12-22-12-ultimax-dvc-subwoofer-2-ohms-per-coil--295-512

Cabinet recommendations:
• Sealed 2.0 cubic ft. (net internal) with 1 lbs. of Acousta-Stuf polyfill, f3 of 36 Hz with a 0.707 Qtc alignment
• Vented 4.0 cubic ft. (net internal, not including driver or port volume) tuned to 20 Hz with a 10" wide by 1.5" high slot port that is 25" long, which yields an f3 of 19 Hz

Sure you want to put it in a sealed box? The f3 of 19hz in a ported alignment looks sublime :T

[JonMarsh]

Looked up that driver:

http://www.parts-express.com/dayton-audio-um12-22-12-ultimax-dvc-subwoofer-2-ohms-per-coil--295-512

Cabinet recommendations:
• Sealed 2.0 cubic ft. (net internal) with 1 lbs. of Acousta-Stuf polyfill, f3 of 36 Hz with a 0.707 Qtc alignment
• Vented 4.0 cubic ft. (net internal, not including driver or port volume) tuned to 20 Hz with a 10" wide by 1.5" high slot port that is 25" long, which yields an f3 of 19 Hz

Sure you want to put it in a sealed box? The f3 of 19hz in a ported alignment looks sublime :T

It's about the transient definition. I did 2cu ft sealed for GF, worked quite nice with a touch of EQ. Model that alignment versus the ported one in Unibox and have a gander at the step response... :W

[jim1961]

It's about the transient definition. I did 2cu ft sealed for GF, worked quite nice with a touch of EQ. Model that alignment versus the ported one in Unibox and have a gander at the step response... :W

I admit, transient definition is important down to 40hz or so. I don't think its as important below 40hz. Do you agree?

[JonMarsh]

Based on comparing a big, very high output capability ported sub that was quite strong down to 18 Hz, versus an IB setup with similar response curve (with slight shelving EQ) and a Q of 0.55, I'll take the improved definition- it's quite audible/feelable, especially compared with so called EBS alignments. YMMV, of course, and individual room acoustics will have an effect.

I used to be making this case to people with just one particular record back in the 70's- Mahavishnu Orchestra, Visions of the Emerald Beyond. Opening cut, a lot of deep fast bass kick drum rolls, which on a sealed system or magneplanars had very well defined drum hits, but with ported systems turned into something more like an organ note. Now, that's a trick test case, I'll acknowledge, but it highlights the issue very quickly.

Ported you can always get more output with a smaller box, or larger if you go TL, but it's a question of which trade-offs are worth while to the individual listener. And of course, the suitability of the driver, as low Qts drivers work well ported, but sealed systems are usually better done with parts in the 0.4 range rather than 0.25 to 0.3.

[jim1961]

Based on comparing a big, very high output capability ported sub that was quite strong down to 18 Hz, versus an IB setup with similar response curve (with slight shelving EQ) and a Q of 0.55, I'll take the improved definition- it's quite audible/feelable, especially compared with so called EBS alignments. YMMV, of course, and individual room acoustics will have an effect.

I used to be making this case to people with just one particular record back in the 70's- Mahavishnu Orchestra, Visions of the Emerald Beyond. Opening cut, a lot of deep fast bass kick drum rolls, which on a sealed system or magneplanars had very well defined drum hits, but with ported systems turned into something more like an organ note. Now, that's a trick test case, I'll acknowledge, but it highlights the issue very quickly.

Ported you can always get more output with a smaller box, or larger if you go TL, but it's a question of which trade-offs are worth while to the individual listener. And of course, the suitability of the driver, as low Qts drivers work well ported, but sealed systems are usually better done with parts in the 0.4 range rather than 0.25 to 0.3.

I agree with your response. The issue I was trying to explore was the issue in a frequency domain and try to gather whether your points have the same merit at 30hz as they do at 60hz. The average bass guitar only goes down to 41hz. So using the Mahavishnu analogy (I own that btw), If your full range speakers went to 40hz, and a ported sub ran below 40hz, would you have the best of both worlds?

[JonMarsh]

Well, it might be an experiment worth trying, but as I mentioned, my own investigations with ThomasW and monster ported sub with HE15 versus quasi sealed IB sub, the latter won hands down. The ported sub sounded like a really good HT sub setup- the IB sounded like live music, because of the dryness and definition. Think about it, for a given impulse, the ported setup has a build up and decay time, which amounts to several cycles- to me, that overhang is audible on most program material (OK, not on Saint Saens C Minor organ symphony, perhaps!)