• Welcome to The Audio Annex! If you have any trouble logging in or signing up, please contact 'admin - at - theaudioannex.com'. Enjoy!
  • HTTPS (secure web browser connection) has been enabled - just add "https://" to the start of the URL in your address bar, e.g. "https://theaudioannex.com/forum/"
  • Congratulations! If you're seeing this notice, it means you're connected to the new server. Go ahead and post as usual, enjoy!
  • I've just upgraded the forum software to Xenforo 2.0. Please let me know if you have any problems with it. I'm still working on installing styles... coming soon.

C1's + 13

I also took into account the floor bounce null issue which nearly all popular modern speakers suffer from. The placement of the woofer is such that the floor reflection null occurs at 650Hz based on Heeman's seating distance of 8 feet. That moves it out of the operating range of the woofer and thus eliminates it. The woofer on the C1 is further from the floor, and while I didn't perform the calculations, the floor bounce null from the C1 should be in the 100-200Hz range, which is will below the new operating range of the C1. This simple addition effectively eliminates the floor bounce null nearly all HT owners have to contend with.
 
JeffMackwood said:
Thanks. I was just above to ask about the electronics / signal diagram when you posted.

But regarding the quote above, I am both with you, and Heeman. I think the 80Hz subwoofer crossover setting is way too high, but I also think that running the F L/R on large with no crossover is perhaps not the best as well. Why not a 40Hz setting? There are some equivalent-to-LFE frequencies present in the F L/R channels of some source material, material that the dedicated subs, and not the new bass bins, should be handling - IMHO.

Jeff

ps. Need at least one more woofer bin under the centre! :)

ps. Congrats Keith!
Click to expand...


That's a very good question and one which is not easily answered. The woofers we designed and he installed are capable of incredibly musical bass to 23Hz in his HT and thus do not need a subwoofer to produce all the bass anyone could ask for. However, they cannot be placed ideally for the best sub-bass performance. So, that raises the classic stereo subs question - are stereo subs located in the Left ad Right speaker position usually better than mono sub(s) placed for ideal room excitation?

In my system which also has bass bins for the main left and right speakers (which are not as good as Heeman's), I could get bass to about 30Hz without any restrictions. But, I chose to use my Infinite Baffle subs below 40Hz, the lowest my Pre-Pro will allow me to set the bass management crossover. In my case the IB subs can play at least an octave lower than my bass bins and louder at 30Hz. In Heeman's rig the subwoofers play a little lower, but not significantly, and the max SPL of either his new bass bins and his PSA subwoofers are both greater than he would ever ask them to do. This makes the argument less obvious to answer.

To add to the complications, setting your front speakers to Large does not eliminate the subwoofers from operating when listening to surround content. A concert video will still have lots of content in the LFE channel even if all the other speakers are set to large. The only time the subs will be silent is when listening to stereo content, which Heeman doesn't do that often. So, it isn't like he won't be enjoying his subwoofers by setting his front speakers to large.

I have encouraged Heeman to spend a dozen hours, or so, with his front speakers set to large to grow accustomed to the sound, and enjoy his music and concert videos. Then he can reactivate bass management on his front speakers and hear if there are any improvements he prefers. Ultimately, I don't think there is a theoretical way to answer this question. He need to experience it and decide what he prefers - even if his preference is solely emotional.
 
Can't imagine how great those C 1's must sound now. It would seem to me you took the hardest, but best pathway to achieve your audio bliss.
Great work guys.
 
Here's the shopping list we came up with:

Madisound
  • 2ea Scan-Speak 32W/4878T01 Revelator 13” Woofer – 4 ohm
  • 2ea Bennic Round Input Cup with Gold Binding Posts R-CUPS (4.14”)
  • 2ea Precision Sound Products 4” Flared Vent Kit (PSP4-BKHT)
  • 3ea QC250-R Red Quick Connect 0.25 inch (for woofer)
  • 3ea QC250-B Black Quick Connect 0.25 inch (for woofer)
  • 3ea QC205-R Red Quick Connect 0.205 inch (for input terminals)
  • 3ea QC205-B Black Quick Connect 0.205 inch (for input terminals)
  • 18+ Appropriate Screws (Bolts/Nuts) and Rubber Washers for mounting speaker (min. 9 per speaker)
Additional Parts
  • 2ea ¾” MDF Sheets (Most are thicker and may require adjustments to plans)
  • Speaker wire (light, flexible, 16AWG min, up to 13AWG)
  • Quality wood glue (Titebond or Elmers Professional Wood Glue)
  • Rubber / Mineral Filled Rubber adhesive sheets (eg. Noico 80 mil butyl sound deadening mat)
  • Flexible silicon sealant (or maybe that Flexseal stuff from TV)
  • Finishing materials, if needed
  • miniDSP 2X4 HD w/Plug In for crossover usage
  • RCA cables to connect miniDSP
  • Two Channels of clean, high current amplification (Heeman chose to use two channels in his MonoPrice Monolith amp)
Necessary Audio Tools:
  • PC to program miniDSP
  • Measurement gear capable of accurate frequency response measurements (True RTA with calibrated microphone)
 
Dentman said:
Can't imagine how great those C 1's must sound now. It would seem to me you took the hardest, but best pathway to achieve your audio bliss.
Great work guys.
Click to expand...

I'll defer to Heeman, but I don't think this was very hard at all. Heeman knows electrical wire stuff and does enough woodworking at home to use all the tools required for making cabinets. MDF is easy to work with - sometimes too easy.

In fact, I think a good 70% of the stress Heeman experienced was of his own making thinking this project would be much harder than it actually was.
 
Heeman just sent me this - the actual costs for the project (does not include two channels of high current amplification):

upload_2017-12-3_10-35-56.png

Note that this list includes all the necessary tools he didn't have which will likely be used for other projects in the future, such as clamps, router bits, and saw blades.

Note also that this list does not include any of the audio measurement gear nor the paint or finishing supplies he will likely utilize in the future.
 
The one thing I hope to do when I get to visit Heeman is drag one of these speakers out onto his driveway and do a ground plane measurement and compare the real world results with my calculated predictions. Assuming the manufacturer's specifications where very close to the parameters of the woofers received, they should be close to identical. But, if they are way off, I might yank out one of the woofers and measure it separately to see if their tolerance to spec is excessively large.
 
Franklin, thanks for taking your valuable time to support this great project!

You were extremely patient with me during this process, including all the measurements that I made last night, capturing them and texting screen shots to you.

I knew that when I first fired these woofers up in my system, that they were running way to hot. Adjusting the gain on the 2 woofers were simple with the MiniDSP Software.

To answer a few of the questions above.

Yes I am still running the (2) PSA XS-30 subs.

I made measurement with the subs off and also crossed at 80 and 40 Hz. The performance was the best with them crossed at 80 Hz.

I am driving the woofers with 2 of the 3 channels of the Monolith Power Amp, it is rated at 375 W/channel with a 4 ohm load.

Now I am driving my surrounds with a Parasound HCA-1000 Power Amp that was in storage.

Now that the system is balanced, the sound is incredibly clean. My friend the SPL Meter is telling me that the system is playing much louder that I actually think. SPL is no longer an issue with my system which was one of the goals of this project.

The ports on the C1's remain plugged. The drivers on the C1's used to move like crazy, it is nice to see them not move hardly at all. They are no longer stressed.

The plots recorded last night show a nice curve, not perfect, but damn good! I look forward to using some of the other features of the MiniDSP to fine tune in the future. Right now I am just sitting back and enjoying the excellent sound.

Franklin, once again, thank you!!
 
Building these cabinets was much easier than I could have ever imagined.

However, I will never cut/route MDF in the basement ever again.................. Even with the Shop Vac, the powdery dust was everywhere!

The circle jig worked great.

Clamps are key and probably one of the most important tools needed for a project like this.

Now for more listening......
 
Flint said:
I'll defer to Heeman, but I don't think this was very hard at all. Heeman knows electrical wire stuff and does enough woodworking at home to use all the tools required for making cabinets. MDF is easy to work with - sometimes too easy.

In fact, I think a good 70% of the stress Heeman experienced was of his own making thinking this project would be much harder than it actually was.
Click to expand...
No matter how you look at it, just pulling out your visa card and paying for new speakers is easier, much easier.
 
^ Yes, no doubt, however this was a great project.

Having these woofers designed specifically for my system has some great benefits that I may or may not have gotten with a different speaker.

Barb continued to say "what makes you think upgrading to C2's will accomplish what you want?, What are you going to do if you spend all that money and you are still not happy?" She had a great point. If I could have auditioned the C2's or C60's in my room, that could have been a different story, but that was not possible.

This was the right solution for me.
 
Dentman said:
Yes but it's easier. We were not discussing price. Give the guy the credit he's due.
Click to expand...

Oh! I do!

I thought you were saying this sort of project wasn't worth if you could just go buy some better speakers.
 
heeman said:
Barb continued to say "what makes you think upgrading to C2's will accomplish what you want?, What are you going to do if you spend all that money and you are still not happy?" She had a great point.
Click to expand...
Barb is a most-astute person.

Of course I presented the BEST solution to you quite some time ago, but nooo, you had to go all fancy schmancy flinty do-it-yourselfie and spoil my shot at those C2s.

:)

Jeff
 
Flint said:
Oh! I do!

I thought you were saying this sort of project wasn't worth if you could just go buy some better speakers.
Click to expand...
Oh hell no!!!
In fact I think he would have had a very tough time finding a speaker to cover his needs that could match those C 1's in the middle for anything less then 6 to 8k.
I think if money WAS an issue and he wanted those large dynamics with a nice middle I would look no further then Studio 100's. A good option but he'd lose that great midrange of the C 1's.

I think his choice, with your help was brilliant.
 
Oh, my jealousy runneth over! That was so awesome.

So I think i was able to follow most of the technical stuff... and learned something new for sure (e.g., the floor bounce null).

However, there are questions:
  1. Why the Mini 2x4 HD vs. the non-HD version?
  2. It didn't look like you had done anything to the outside of the box yet. Are you planning to finish it later?
  3. Is there any downside to having the silver side on the dampening material?
  4. Will you play around with different types of crossovers? E.g., LR 24db/octave, or even 12db? Or a Butterworth? (i only know the book parts and not how they'd sound in real life)
 
1) I have had no prior experience with the miniDSP, so I was not confident in recommending it for this job. Other capable crossovers/processors I do have experience which I would recommend cost over $600 for a stereo pair of speakers. The HD version of the miniDSP operates with a ADC/DAC at 24bit / 96khz while the cheaper non-HD version is at 24bit / 48khz. Given the relatively low price for a pair of two way crossovers the HD version was still a great deal. I still don't know if the non-HD version would be audibly inferior, but this way I can be assured that if there is a difference we will be working with a better product.

2) I have made a few recommendations to Heeman on the finishing of the cabinets, but it is his choice on whether or how he does it.

3) The only potential downside I can think of is the possibility of the foil peeling off or bubbling and causing a rattling noise at high SPLs. Really, it should cost more to have foil over the same product without foil, so pricing really drove the choice. This stuff is not cheap for the amount of area it covers, so saving money is always a good idea even if saving means buying what ought to be the costlier product.

4) When I visit Heeman and do the final tuning I will measure each speaker independently and model various crossover methods and choose the one which measures the best and sounds the most natural. As I mentioned in my posts on this topic, a high order L-R crossover is easiest to tune if you don't have the experience, skills, and knowledge of the various crossovers and their resulting performance, both perceptual and measured. That said, it is always important to match the type of crossover between low and high pass so an LR is matched to an LR and a BW is matched to a BW, or a QBW to a QBW. That matters due to phase relationships in the overlap region. But, I've built speakers with 2nd order on the low pass and 4th order on the high pass crossovers before which sounded amazingly better than matching 4th to 4th or 2nd to 2nd.
 
The final finishing of the cabinets has not been decided upon yet..........

Looking at different options, however they will be black and not glossy.
 
You must log in or register to reply here.
Back
Top