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About ligs

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  1. I used to be a research scientist so I am used to pursue a goal for a long time with occasional breakthroughs. As long as we are learning something new and still having fun then we ought to keep going. George
  2. " In the process I relearned what flat bass sounds like. In the end all I needed was even milder equalizer adjustments to get very close to the headphone sound. What I learned was most of the pop and rock vocal music that I listen to does not have very deep or prominent bass. When set properly the bass almost never blurs the vocals nor is it so loud that the vocals are overwhelmed . Original “Won’t get fooled again” by The Who. You can hear every word on headphones. The bass line is surprisingly not prominent on headphones but through 12” ARs it is easy to have heavy mid bass that blurs the vocals" Well said! Here is an in-room frequency response of NHT 3.3 . Some people describes it sounds like a pair of headphones and it has excellent vocal clarity. The vocals from 100 hz and up come from the front drivers while the bass from the side mounted 12" woofer(also know as NHT 1259). My interests in 92 db satellite speaker and passive stereo subwoofers with 100 hz crossover were inspired by NHT 3.3.
  3. Thanks, Pete. Subwoofers are relatively straightforward to construct and can provide the biggest bang for the buck in terms of perceived improvement. A dedicated subwoofer amplifier can further enhance the performance of any subwoofer by combining crossover, equalizer and sufficient power all in one package and is available at a very affordable price.
  4. That old chart has measurements taken from earlier version of crossover and the satellite showing rising response from 80 hz to 1000 hz. The latest version of the crossover has rendered the JBL 127H1/Dayton RST 28 A4 flat from 80 hz to 1000 hz. The individual response curves of RSS 390 HF4 and the JBL satellite are shown below. All except a dip around 160 hz(probably due to the floor cancellation as discussed in many AR/ Allison literature), the new satellite speaker now matches the sub in SPL.
  5. Yes, we are lucky to have a real lumber yard nearby. At Lowes or Home Depot they would warn you the cuts will not be precise enough for cabinet work:) Yes, they cut the holes with a jig saw. But I spent hours enlarging the holes to fit the subwoofer openings. All my satellite speakers including the one using JBL 127H1 woofer will respond to below 100 Hz, so there will be some overlap between them as shown in the graph below. The red trace representing both drivers are in phase acoustically and is louder than the blue line. It is interesting connecting the subwoofer electrical polarity opposite to than of the JBL 127H1 resulted in in-phase acoustic response.
  6. There is a family owned Terry lumber yard near where I live. I purchased two 5x5 sheets of Baltic plywood and they cut into more than 38 pieces with great precision for a very reasonable $30. Fitting them together was very straightforward. This 13-ply Baltic is a great material to work with. The inside of the boxes is heavily braced(front to back, left to right and top to bottom). When done, each empty cabinet weighs 50 lbs about the same as an AR3a. For my generation(born in 1940's), if you wanted something you built it yourself. I still remember my fun with Eico kits, Knight Kits, Heathkits, and Dyna Kits.
  7. Dayton RSS 390 HF4 and NHT 1259 subwoofers. Relative Frequency Response in a Room. Recently I got a good deal on a pair of Dayton RSS 390 HF4 15” subwoofers. So I built a pair of 4.2 ft3 sealed cabinets made of ¾” Baltic Birch plywood and stuffed with about 3 pounds of fiberfill in each cabinet. The NHT 1259 subwoofers are housed in 2.8 ft3 sealed cabinets with about 1.8 pounds of fiberfill each. The 12” NHT 1259 is no longer available. The Dayton 15” subwoofer is still current. It is highly regarded by the DIY community and is made with anodized aluminum cone meaning the cone has stiff exterior ceramic “aluminum oxide” surfaces and it also has a modern magnetic structure with triple shortening rings. Efficiency wise, the Dayton is rated at 91.2 db/2.83 vs 90 db/2.83v for NHT 1259. Driven through a fixed 100 hz low pass (12 mH/200 uf) crossover, both subwoofers had strong response to at least to 31.5hz. Interestingly, the 15 inch Dayton is about 4 db more efficient from 20 hz to 31.5 hz. Both subs provide a smooth satisfying bass foundation to compliment small satellite speakers.
  8. ligs

    AR speaker low frequency perspective

    I found an on-line version of an article by D.B.Keele, jr, who specialized in testing and reviewing (sub)woofers. http://www.gammaelectronics.xyz/audio_11-1992_sub.html I thought it would be interesting to include some of his findings in the discussion of bass reproduction. Figure 1 is the frequency response of 4 subwoofers. Figure 2 is maximum peak sound output vs frequency including the effects of room gain. Therefore the typical manufacturers’ spec on frequency response (measured at 1 w or 2.83 volts) does not predict completely how the speaker will perform at realistic sound level in your room.
  9. My guess is around year 2000. They look like this. Yes it has a 6.5 " heavy duty cast frame woofer but is sealed. http://xcsdfarew.blogspot.com/2013/03/jbl-studio-s36aw-ii-3-way-high.html I am surprised it has a very complex crossover.(mixed 2nd and 3rd order slopes). I was playing them as full range in parallel with NHT 1259's. The rest of Studio series are vented. Stereophile has a review of its 8" big brother S-38. https://www.stereophile.com/standloudspeakers/365/index.html George
  10. Experimenting further with a LCR trap in woofer’s crossover removed a slight hump around 1000 hz. This improved the vocal quality of JBL127H-1/RST 28 A-4/NHT 1259. Here is a comparison of my DIY satellite vs commercial JBL Studio 36ii (6" three -way)and Infinity Reference R162(6" 2-way) speakers. Above 2000 hz all three have very similar response curves. Please disregard 200 hz and below because of the room effect. I can live happily with any of the three choices. On louder passages, the JBL127 H1 sounds more relaxed, perhaps its low distortion is a contributing factor. George
  11. I have a very rough idea about the frequency responses measured in my room with the help of a Radioshack analog SPL meter and Stereophile test CD. The response cures will not be comparable to any other lab measurements. These curves are not calibrated and are meant to serve as a comparison purpose. The microphone is placed about 1 meter between the JBL woofer and tweeter. Keeping that in mind. It does appear that JBL 127H1 satellite without NTH 1259 begins to roll off below 200 hz. This is due to the very small sealed box volume , a 50 ohm resistor across woofer and the placement of the satellite without room boundary reinforcement. Combining with NHT 1259, the entire bass region (red and green lines) becomes flatter and extends at least to 32 Hz. As shown. George
  12. Yes, 32 Hz refers to the combined (connected in parallel) response NHT 1259 and satellite with JBL 127H1. NHT 1259 has an in-line low pass passive crossover at around 100 Hz as in NHT 3.3. The satellite is about 2 ft away from the backwall and just sit on the boxes containing the sealed NHT 1259's. Madisound used to sell a version similar to NHT 1259 but is no longer available. http://www.madisound.com/pdf/MAD1259.pdf George
  13. In my main listening room I am using Dayton SA1000 with a pair of HSU TN1220's subwoofers which have received a rave review in High Fidelity magazine. http://www.gammaelectronics.xyz/audio_1998_Aug--hsu.html Also I am using my pair of NTH 1259's as the woofers of my 92 db satellite speakers(JBL 127 H1 and Dayton RST 28 A-4). They are flat to 32 Hz and then dropping off rapidly in the room. Therefore I need to use HSU TN 1220 for the last octave. In my family room with Samsung smart TV, I am using a pair of Infinity Reference R162's and a pair of HSU HRS10's driven with a Dayton SA500 Let me try to upload the third page of the article mentioned before. George
  14. Here is page 3 of the same article. BTW, I am using a dedicated subwoofer amplifier for my subwoofer(s). https://www.parts-express.com/dayton-audio-sa1000-subwoofer-amplifier-rack-mountable--300-811 Dayton Audio SA1000 Subwoofer Amplifier Rack Mountable. Model SA1000. It has a variable 24db/oct low pass crossover and a parametric equalizer to fine adjust the frequency response. George