Page 3 of 3 FirstFirst 123
Results 31 to 39 of 39

Thread: My Hartsfield DIY Project

  1. #31
    Senior Member Eaulive's Avatar
    Join Date
    Aug 2009
    Location
    Back in Montreal
    Posts
    1,204
    I don't care if they don't sound so good (even if I'm sure they do ), the craftmanship is awesome... all the complex angles are a real work of art.
    Bravo!
    My avatar: 4520 loaded with 2225H on E140 frames,
    1x B&C 12PE32 on custom front loaded horn, 2x 2426 on 2370.

  2. #32
    Senior Member Mike F's Avatar
    Join Date
    Feb 2011
    Location
    Montreal, Canada
    Posts
    265

    A tip of the hat to you

    Very nicely done. Can you describe your upstream electronics and listening environment?

  3. #33
    Member
    Join Date
    Jul 2013
    Location
    Dallas, USA
    Posts
    39
    Thank you everyone for your comments!

    As for my electronic components:

    VPI Scout turntable with a Soundsmith Zephyr moving iron cartridge
    ProJect Phono Box S phono preamp
    Project Pre Box S Preamp
    As for amplifiers: I design my own. I am a trained EE with an analog design background. I started building tube guitar amplifiers then moved into HiFi amplifier design. I don’t intend for this to be a sales add but please visit www.bandwidthaudio.com for more information on the amplifier I am using.

    The weakest link in my system is now my room:

    I finally purchased a calibrated measurement microphone, which I use with Room EQ Wizard. I first realized that I was not getting the high frequency extension I wanted so I changed the crossover by strapping the tweeter L-Pad to the input of the speaker rather than off the already attenuated midrange horn.

    However, with the high frequencies now measuring flat past 20KHz, the stereo image began to blur. I think the reason for this was due to mounting the tweeters in the pockets of the bass horn mouth, which puts the tweeters far off axis. Also my measurements hint at some lobbing at specific frequencies due to reflections off of the top of the cabinets and exit of the bass horn. (I would imagine that the Paragon suffers form this badly since they are mounted way into the mouth of the bass horn)

    To fix this I ended up adding 077 tweeters on the top of the cabinets in a small cradle. Now there are minimal reflections and they are on axis with the rest of the system. The tightened the stereo image back and gave the high frequency content I was missing. Note: Keeping 10KHz to 20KHz flat really does make a huge difference! Everything opened up compared to the old 075 setup and I get the breath in well-recorded vocal tracks.

    It is also amazing how much high frequencies change the perception of bass frequencies. For instance, the imaging of upright or electric bass is much improved since all of the cues (like fret buzz and clacking) help track the spatial location of the instrument in the room. Since low frequencies do not have strong directionality, the sense of location only comes form the very high frequencies produced by these instruments.

    Lastly after much listening I swapped the JBL E145s for TAD 1603 woofers. These increased the bass weight slightly and improved the low frequency response. The bass is a little less fast but I think overall better rounded with a less “honky” feel. I think the E145 loses efficiency shapely below around 40Hz reducing the output and creating a slightly honky feel.

    With these changes I am finally done with the speakers! My measurements show my room is the next challenge. There are lost of modes at low frequencies causing very uneven response. There is a fairly large null/roll off at around 40Hz in my listening position then a large constructive node at 30Hz causing a very sharp peak in the response.

    I know these nodes don’t help my impression of the E145, but the TAD 1603 certainly works better with my room as it stands now.

    Cheers,
    Matt

  4. #34
    Senior Member
    Join Date
    Apr 2016
    Location
    Winnipeg Manitoba
    Posts
    183
    Quote Originally Posted by mbeards View Post

    With the advice from John Wolf from Classic Audio Loudspeakers (who has been selling some very nice Hartsfield reproductions for some time now), I moved to a much simpler crossover arrangement.

    The woofer is directly wired with no crossover. As advised by John, the E145 will naturally roll off due to the cutoff frequency created by the bass horn. There is no need to force attenuation electrically.

    The 2441 has a high pass filter with 12dB/octave slope crossed over at 500Hz. I used a capacitor in series with the driver so it runs flat out from 500Hz and up. A 16ohm L-pad takes care of the necessary attenuation.

    The 075 tweeter has a 12dB/octave crossover set at 9Khz with a cap in series with the driver and a second L-pad for attenuation.
    How is this working for you? I built a pair of Hartsfields last summer and I am running active crossovers with three amps. I'm thinking of changing to just a single amp to simplify things.

    To accomplish what you did, do you just use a capacitor in series and then an inductor in parallel, followed by a l-pad for both mid and high? I found information online for the values of the inductors and capacitors for the desired crossover points. I'm assuming I should use 8 ohm l-pads because my drivers are 8 ohm? What about the wattage of the l-pads, is higher better?

    I'm running 130A low, 2446 mid, and 2402 or 2404 tweeters. Can't make up my mind on the tweeters yet.

  5. #35
    Member
    Join Date
    Jul 2013
    Location
    Dallas, USA
    Posts
    39
    Quote Originally Posted by robertg View Post
    How is this working for you? I built a pair of Hartsfields last summer and I am running active crossovers with three amps. I'm thinking of changing to just a single amp to simplify things.

    To accomplish what you did, do you just use a capacitor in series and then an inductor in parallel, followed by a l-pad for both mid and high? I found information online for the values of the inductors and capacitors for the desired crossover points. I'm assuming I should use 8 ohm l-pads because my drivers are 8 ohm? What about the wattage of the l-pads, is higher better?

    I'm running 130A low, 2446 mid, and 2402 or 2404 tweeters. Can't make up my mind on the tweeters yet.
    Great to here there is now another m with a pair of Hartsfields!

    My crossover is extremely simple. I have attached a drawing of the schematic.

    Name:  JBL Hartsfield Crossover.jpg
Views: 1222
Size:  91.7 KB

    I use a 16ohm L-pad for the midrange and 8ohm L-Pad for the tweeter both from Parts express.

    16ohm: https://www.parts-express.com/parts-...6-ohm--260-261

    8ohm: https://www.parts-express.com/speake...8-ohm--260-252

    I removed the original JBL autotransformers from the crossover plates and mounted these with the JBL knobs for a factory look.

    My final driver lineup which I have been running for the past 2 years is:
    TAD 1603 woofer 8ohm
    JBL 2441 16ohm compression driver with Truexten Beryllium diaphragms
    JBL 2405H 8ohm sitting in mount on top of the cabinet


    • The impedance mismatch with the 2441 may seem odd, but the higher impedance helps knock down the efficiency a bit compared TAD 1603 so I can use a little less attention in the L-pad for the mid-range compared to running all 16ohm drivers. The net impedance curve is very kind on amplifiers and is very flat at 7-8ohms.


    • No doubt the TAD 1603 is the best 15” woofer I have ever heard. It excels in this cabinet compared to the E145’s I was using. With the speakers placed near 2 symmetrical corners of my listening room for room gain, the speakers are roughly -10dB at 30Hz! Keep in mind that this bass is extremely accurate, and miles ahead of any subwoofer on the market.


    • Also, I would recommend the 2405H tweeters based on my experience. I get superb imaging through the entire bandwidth with this arrangement. Female vocals never sounded more real. Dianna Krall’s “I don’t know enough about you” sounds like she is in the room singing since the sound field of her voice is roughly the size of a human head in the center of the room.



    BTW if anyone is in the Chicago area and wants to hear these, my door is always open.

    -Matt

  6. #36
    Senior Member
    Join Date
    Apr 2016
    Location
    Winnipeg Manitoba
    Posts
    183
    It's funny you replied to this today, I just ordered parts to make a crossover. I believe these are first order crossovers, 6db/octave? I'm going to go with second order, 12db/octave. They have a capacitor and inductor. Building a crossover can be extremely complicated, and I know just enough to be dangerous.

    I have a DBX Driverack now, so I can control everything. My ear can't hear a difference when I make major changes. If I change the woofer and mid to roll off early, or run flat out, I can't tell.

  7. #37
    Junior Member Theopholis's Avatar
    Join Date
    Feb 2016
    Location
    Thousand Oaks, CA
    Posts
    25
    Absolutely gorgeous. I didn't see it in the thread. What wood veneer and stain did you use?

  8. #38
    Member
    Join Date
    Jul 2013
    Location
    Dallas, USA
    Posts
    39
    Quote Originally Posted by Theopholis View Post
    Absolutely gorgeous. I didn't see it in the thread. What wood veneer and stain did you use?
    The veneer is movingui. I believe it is found in the African Congo. My friend Fred of Heartwood Custom Interiors had a large quantity stashed away for years waiting for a special project. He got it from someone who long since retired from professional woodworking. No doubt it came from a very old tree.

    The finish was a custom mixed satin polyurethane stain with a few layers of clear over the final color. The entire internals of the cabinet were sprayed with clear polyurethane before final assembly to provide some resistance to moisture.

    Thanks!

  9. #39
    Junior Member Theopholis's Avatar
    Join Date
    Feb 2016
    Location
    Thousand Oaks, CA
    Posts
    25
    Quote Originally Posted by mbeards View Post
    The veneer is movingui. I believe it is found in the African Congo. My friend Fred of Heartwood Custom Interiors had a large quantity stashed away for years waiting for a special project. He got it from someone who long since retired from professional woodworking. No doubt it came from a very old tree.

    The finish was a custom mixed satin polyurethane stain with a few layers of clear over the final color. The entire internals of the cabinet were sprayed with clear polyurethane before final assembly to provide some resistance to moisture.

    Thanks!

    Well, looked it up on E-Pay and some other online wood stores. A 4 by 8 foot sheet was almost 200 bucks! I'd actually go for it, but it's not nearly as gorgeous as yours. They did have some very nice looking veneers, but they were limited to 7.25 inches wide. Maybe after I've veneered a few other projects, I'll think about buying the strips and joining them.

    Enjoy your system!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Toploader Hartsfield Project
    By Oldmics in forum Lansing Product DIY Forum
    Replies: 19
    Last Post: 05-31-2012, 08:29 AM
  2. Fundraising request; donations to Lansing Heritage Project May loudspeaker project
    By mikebake in forum Lansing Product General Information
    Replies: 7
    Last Post: 04-21-2011, 12:37 PM
  3. Hartsfield, HELP !!!
    By EBJ in forum Miscellaneous Gear
    Replies: 5
    Last Post: 04-15-2007, 03:49 PM
  4. Project May, similar privat project?
    By Flodstroem in forum Lansing Product DIY Forum
    Replies: 14
    Last Post: 02-21-2007, 02:42 PM
  5. Fundraising for Project May Loudspeaker project
    By mikebake in forum Public Forum - Announcements
    Replies: 0
    Last Post: 02-10-2004, 07:15 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •