First trials of active horn speaker
- Thread starter morricab
- Start date
Hi Bill,
No, it seems pretty quiet even through the 110db horns. There was noise in earlier trials but it seems it was the amp rather than the minidsp. With the current amp there is only a tiny bit of hiss that is only audible right at the horn.
Update:
I have now finally settled on 1Khz and 2nd order LR. Tried other frequencies and slopes and kept coming back to this as providing the best coherence and natural feel. The sound is very open and natural with very good imaging and soundstaging (good depth on well recorded classical). Tonal selectivity is outstanding, so even complex works it is very easy to distinguish tonality of individual instruments. Resolution is outstanding as well. Punch and drive at this point is good but not quite at the Odeon La Boheme levels. I think this will be resolved in Stage 3 but I will continue to play with time alignment and low frequency balance to address the minor issues there.
At this point, stage 2 is basically complete and Stage 3 will commence sometime next year. I have a friend who is a profession furniture maker who can make my cabinet designs at a much higher level than I ever could (I am good at making things work but terrible at finishing and detail work). Stage 3 will include a new cabinet for a double TQWT where the 8 inch Supravox and two 10 inch woofers (type tbd.) will feed a common TQWT with the Supravox on the front and the 10 inchers on the backside. Probably the initial version of Stage 3 will be active/passive where the full range signal is sent to the Supravox but the 10 inchers will have a passive low pass filter.
I have now finally settled on 1Khz and 2nd order LR. Tried other frequencies and slopes and kept coming back to this as providing the best coherence and natural feel. The sound is very open and natural with very good imaging and soundstaging (good depth on well recorded classical). Tonal selectivity is outstanding, so even complex works it is very easy to distinguish tonality of individual instruments. Resolution is outstanding as well. Punch and drive at this point is good but not quite at the Odeon La Boheme levels. I think this will be resolved in Stage 3 but I will continue to play with time alignment and low frequency balance to address the minor issues there.
At this point, stage 2 is basically complete and Stage 3 will commence sometime next year. I have a friend who is a profession furniture maker who can make my cabinet designs at a much higher level than I ever could (I am good at making things work but terrible at finishing and detail work). Stage 3 will include a new cabinet for a double TQWT where the 8 inch Supravox and two 10 inch woofers (type tbd.) will feed a common TQWT with the Supravox on the front and the 10 inchers on the backside. Probably the initial version of Stage 3 will be active/passive where the full range signal is sent to the Supravox but the 10 inchers will have a passive low pass filter.
New update:
I have finally measured the system and I have to say that it was measuring surprisingly flat out to 20Khz (down only a couple db) and quite flat overall (about +- 3db in-room). Through the midband (from about 250hz to 1Khz) tighter and a bit of a bump around 50 hz and a bit of a dip between 100-200hz (seems to be a common issue from floor bounce). I did bring down compensation I had added to get better extension from the compression driver with constant directivity horn but it seems I was overdoing it. Now I have about 3db above 7khz that gives some nice air without sounding bright.
I am also buying now Iwata 600 horns from Autotech to fit my 1 inch Beyma CP350Ti driver, which I still haven't tried out yet with the cheap and cheerful 18 sound XT120 horns (20 bucks a piece). The Iwatas are about 11.5 inches wide (the XT1464s I use now are around 15 inches wide) and will be good down to about 900hz. Based on the data from Beyma on the CP350Ti, it should be able to go down quite low for a 1 inch CD (data shows at least to 600hz or so), so I can try this driver/horn with the exact same crossover frequency...but perhaps a 4th order LR filter instead of a 2nd order one (of course at lower levels this might not be an issue). Let's see but it will be a few weeks before I get it (they make to order).
If the one inch driver works just as well at lower frequencies but better at high frequencies then I might explore other drivers, although on paper this driver and the CP380m look pretty hard to beat. The distortion on the CP350Ti is very low compared to many CDs I have seen where data is available...especially in the higher frequencies.
I have finally measured the system and I have to say that it was measuring surprisingly flat out to 20Khz (down only a couple db) and quite flat overall (about +- 3db in-room). Through the midband (from about 250hz to 1Khz) tighter and a bit of a bump around 50 hz and a bit of a dip between 100-200hz (seems to be a common issue from floor bounce). I did bring down compensation I had added to get better extension from the compression driver with constant directivity horn but it seems I was overdoing it. Now I have about 3db above 7khz that gives some nice air without sounding bright.
I am also buying now Iwata 600 horns from Autotech to fit my 1 inch Beyma CP350Ti driver, which I still haven't tried out yet with the cheap and cheerful 18 sound XT120 horns (20 bucks a piece). The Iwatas are about 11.5 inches wide (the XT1464s I use now are around 15 inches wide) and will be good down to about 900hz. Based on the data from Beyma on the CP350Ti, it should be able to go down quite low for a 1 inch CD (data shows at least to 600hz or so), so I can try this driver/horn with the exact same crossover frequency...but perhaps a 4th order LR filter instead of a 2nd order one (of course at lower levels this might not be an issue). Let's see but it will be a few weeks before I get it (they make to order).
If the one inch driver works just as well at lower frequencies but better at high frequencies then I might explore other drivers, although on paper this driver and the CP380m look pretty hard to beat. The distortion on the CP350Ti is very low compared to many CDs I have seen where data is available...especially in the higher frequencies.
Would be nice to see some measurements you described... and of course a pink noise measurement of the combination Iwata & Beyma in nearfield (around 1m in front of the horn) without any crossover (fullrange)
It will be a few weeks before I get the Iwata. In the mean time I will see if I can take photos of the measurements (its on a 1/6th octave RTA) and also try out the Beyma CP350Ti with the 18 Sound horn as well.
Near Zürich (Regensdorf). We can meet up sometime.Fine, just curious about it
Attached a oic of my Mid-High-driver
BTW, were in Switzerland you reside? I'm living at the lake of Constance...
I was using it for two things: 1) to provide AD conversion for my analog...this failed to sound good so I am looking for another solution for the analog. 2) A measurement tool as I have a Behringer microphone and it has a pink noise generator and 1/6th Octave RTA.
For digital itself I use the minidsp nanodigi that feeds two external DACs that then feed analog to two small tube amps.
I will either get a good analog active xover or a better AD converter...not sure my direction on that front yet.
I see...
to 1: understanding this topic, the AD-converters must be the best you can find
to 2: agree, a dsp is a very helpful tool for neasuring and adjusting
... and I got to the samo point analog x-over or digital x-over. During planning of an dsp of my own requirements - initial costs of around € 10'000.00 - I thought to try it first with analoge x-over... purity of phase is more important and currently I'm experimenting with active xover and line-level xover at the inputs of each amplifier
Iwata 600s should be here by early March. In the meantime, I might try to get either a pair of Radian 475pb or B&C DE250s to compare with my Beyma drivers. Another option would be a Faital Pro or BMS driver. OR a JBL 2425 or 1 inch ALTEC, ie. old school.
Here's a link for the DE250 - good price:
https://en.toutlehautparleur.com/co...rs-de250-16-ohm-1-0-inch-throat-diameter.html
I think that a 1" is ok for this application... old school Altec or JBL are fine drivers. In my current Hornsproject I use B&C above 2.5K and the sound pattern are very good. There are so many drivers for trying out. If you will choose the kings way then TAD 2001 are, in my opinion, one of the best you can buy for the money
https://en.toutlehautparleur.com/co...rs-de250-16-ohm-1-0-inch-throat-diameter.html
I think that a 1" is ok for this application... old school Altec or JBL are fine drivers. In my current Hornsproject I use B&C above 2.5K and the sound pattern are very good. There are so many drivers for trying out. If you will choose the kings way then TAD 2001 are, in my opinion, one of the best you can buy for the money
I have swapped out my Beyma CP755Ti+XT1464 horn with CP350TI +XT120 horn and reset the crossover to 1.5khz. Sounds pretty good once levels were readjusted! Need to measure and tweak but could be at least as good. Iwata comes end of February.
Sometimes it can be good to jump a step back... you're still using the DSP now? I would try it out with a Line-Level-crossover at the input of the amps. Delivery time of the Iwata decrements from day to day
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