Jessie,

I was trying to evaluate the gain of my amplification in respect to larger room and again was thinking about your case. I think something that you do it not correct. You are complaining that you have not enough gain in upperbass, but I think you have not properly set gain reference point in your playback. You need always have gain reference point, which most likely will be the channel with lowest sensitivity. Let see how it done in Milq. It is milliamp or not - it is irrelevant, we are taking about gain now.

The bass channel is chosen as a reference gain channel, marked as “A”, and everything is measured in respect to it gain. In the Milq you see it running wide-open. The 30K resistor in the input crossover and the green resistor of bias do not form a voltage divider as they are refers to different sores and the shunting resistor is 1Meg   

The upperbass channels make as “B” sits behind voltage divider (30K and 12.1K to ground). I do not remember but I think it doe 3dB. Pay attention that the upperbass runs from ½ of the tube, so proximally 1-2 db also is lost to the running 3C33C with a half-plate.

The gain of Fundamentals Chanel “D” is heavily killed by attenuator in secondary.

 The midrange “E” runs in my case full open at line level.

In your case you run your bass channels from a separate amp and the horn channels from Lamm ML2, right?  Lamm has a LOT of gain, much more then Milq, I think it is 26dB. It has 26dB gain and will out 17V into 8R at 1000Hz. This is a LOT; you most likely have a preamp that has 5-15dB gain – so look at the voltage that your playback can swing.  For instance your Vitavox S2 driver in my room and from 8-9 feet needs 250-500mV to sound at comfortable level.  With 1V it will scream very loud. If you remember at the time I used Lamm ML2 and drove my S2 from it I has 14dB voltage divider and used 4R ML2 tap. So, if you run your S2 from wide-open ML2 then it would not be a surprise the you have no other channels match it.

What you need to go it to find how much gain you need. I do know what preamp you use but as a rule- connect it to the less sensitive horn channel – let pretend that it will be your upperbass. Run the channels at it max out and to see how loud it gets. You need to be able to play very loud with your volume control set at 60-70% of the full gain. After you find this configuration then begin to roll off your MF and HF channels until they match your upperbass. I do feel that you will attenuate your S2 quite aggressively. You might even put some 16R LPAD before S2 and to use it for messmates, determining how much you need to attenuate it (do not use it for listening as the LPAD inductance will kill HF). So connect your wide open upperbass and your MF behind the LPAD. Then run a 20-20000Hz sweep and adjust the LPAD until your upperbass will have the same out as your MF. Then measured the LPAD’s impedance to one and another side and you will have your resistors for your voltage divider.  Replace the LPAD’s with none-inactive fixed restores of 1W-5W and your will be all set.

Jessie, I do think that you run your MF too hot. Where is the volume control setting in your preamp when you run your playback too loud? I presume that it at 20-30% of the full scale….

"...What you need to go is to find how much gain you need. I do know what preamp you use..."
 
Currently using an L1, but normally use an L2 (I'm repairing the L2; a tube socket failed and resulted in damage to some capacitors; Lamm sent new parts). I made a voltage divider (attenuator) to place before the input of each ML2, which attenuate either 14 or 16 dB; its been a while since I made them.

"...but as a rule- connect it to the less sensitive horn channel – let pretend that it will be your upperbass..."

It is.

"...Run the channels at it max out and to see how loud it gets. You need to be able to play very loud with your volume control set at 60-70% of the full gain. After you find this configuration then begin to roll off your MF and HF channels until they match your upperbass. I do feel that you will attenuate your S2 quite aggressively. You might even put some 16R LPAD before S2 and to use it for estimates, determining how much you need to attenuate it (do not use it for listening as the LPAD inductance will kill HF). So connect your wide open upperbass and your MF behind the LPAD. Then run a 20-20000Hz sweep and adjust the LPAD until your upperbass will have the same out as your MF..."

This is more or less what I did, though I did it by ear, while listening to music (I have not yet used test equipment to measure the results).

"...Then measured the LPAD’s impedance to one and another side and you will have your resistors for your voltage divider.  Replace the LPAD’s with non-inactive fixed restores of 1W-5W and your will be all set..."

Though I have not yet done it, taking into account the destructive effects of the L-Pads (see previous posts), this was going to be my next step. I may first try using 8 Ohm versions of the drivers in the upper-bass horns.

I'm currently back to using L-Pads only on the lower-mid horns (S2 into 180Hz horns).

"...Where is the volume control setting in your preamp when you run your playback too loud? I presume that it at 20-30% of the full scale…"

Using the L2 with afore-mentioned voltage dividers/attenuators (before the ML2s), the volume setting is usually pointed up around 12 o'clock (50%); a bit more during the day, if the gf is not around. More than that starts to be too loud.

Thanks for your comments,

Similar to the famous sexist tail that women can be only ether pretty or smart the midbass horns unfortunately behave in the very same way: they can be only nicely placed in a room or they can sound good. You want the horn to place in a specific location of your room as it feel good for your house décor and living habits and it turns out to be the worst location for them from the perspective of About speakers Imbedded Macro-Positioning. Sucks!

http://www.goodsoundclub.com/Forums/ShowPost.aspx?postID=4421

It looks the acoustically the default location of your horns is not the best in your room.

I would discard the first two images with both horns playing they are irrelevant at this point.  Let look at the image 3 and 4 from above: Left wall and Right wall.  It is very clear the right wall is much more interesting from upper-bass Macro-Positioning pint of view.  You see the response is more dense and with much more significant LF. Those minor differences in decay at the bottom knee are VERY auditable. I would like to be able to see the grid better, the horizontal lines to see detail but it still is very obvious. Still, you alternative wall position might not be the best in the room and you might have even better location. I do not know how the acoustically better locations are better from the perspective of your living objectives.

Anyhow, let see what you have with your upperbass and what you can do.  The usable image would be the third from the top (it has no number). That is OK response but you need to set a proper reference level for this channel. This is VERY important. Let me to explain what I mean. If you look at the response of the horn then probably the gray line on my image below would be the channel reference. It means the other channels need to be balanced to the gray line. What you need however to do is discard the response of the channel and to set the reference level that you would it to be. I would propose a few dB lower. Take a look at the yellow line that I feel much be you reference level:

Looking at the yellow reference line you will see that horn overshoot it but do not let it to bother you. If you implement let say 450Hz filter and add 2-3dB of the upperbass out then you virtually increase the output of your m upperbass in the frequencies that you are looking for. Be advised that you will have a LOT of problems to do it as it is very hard to low-pass of this driver with speaker-level crossover as the coil the crossover will talk with inductance of the driver and combined coil will be much lower. You would need to use a coil 3-4 times larger then what calculation would suggest but this overly large coil would talk too much with your MF channel. Multi-amping will kill the problem and the crossover in the amp will not be seeing the driver inductance. Using the speaker level crossover you need to use larger coil.

So, you roll off the upperbass sooner then the channel would like you to do and boost 2-3 dB of the channel’s gain. You might not have those 2-3dB driving the thing from a single amp. To get 3dB more you will need to go to another tap but it would make the output tube to be loaded harder at the frequency of given channel and might make the sound too slow. Also, do not forget that you use first order filets and change of the loading for a given channel will very much affect loading for other channels, the last picture shows it very well, in fact ML2 with feedback handles it much better then other amps would do.  So, what you need to do if you need more gain but do not have it? You need to drop the level of your other associated channels. It would not be a good idea to do it for bass channels as adding resistors would affect damping. However for HF channel adding resistors (dividers or juts single resistors) would be fine. Find a non-inductive resistor (very important) of a few watts and use it with your MF driver, driving it for a few dB doe and matching your yellow reference line.  Do the same with tweeter and fundamental channel and your will have proper upperbass balance for your system.

I do not know what kind bass your use but add the LB channel to the mix (still using the NEW yellow line as reference). Then you would need to do a very important thing- to fine tune what would be your Yellow Reference Line (YRL). At this point your YRL is purely arbitrary but you need to bind it to you room.  Here are some techniques that you might find useful. Shut down your fundamental channel (still ONLY for one left or right channel) and use ONLY MF and Midbass to get the sound that you feel is right. It shell be a proper balance between the violins/violas and cello section in complex (very important) music. I uselessly use Vein or Berlin Philharmonic only for reference balance; use what performance you fine is right for you. After you set up your MF and Midbass and feel that you have attenuated MF good enough to have proper balance then add bass channel. If your MF/Midbass balance is correct then running your bass channel a few dBs lower then YRL or higher YRL shall NOT make you to wish to change the MF/Midbass balance. Do the same with tweeter and then with tweeter and bass. After you do feel confident about your MF/Midbass balance than begin to inject your Fundamental Channel. Start it from 15dB down and begin to add it (check the phase) very slow until you begin to recognize the very first sighs of it auditable contribution.  The auditable contribution of Fundamental Channel will be partially from the Channel itself and partially from the fact that the Channel will affect the response of you Midbass Channel. It is not predictable and you need to play with it for a bit. Disregard the measurable date you will be getting at this point. Remember, you MF/Midbass balance is all set and you now need to see if adding of your Fundamental Channel will be able to compromise your feeling about the MF/Midbass balance. This is a bit tricky and you would need to spend time with it. The key in here is to find out HOW the use of Fundamental Channel will revise your view of MF/Midbass balance. You might decide to change the MF/Midbass balance (via the MF resistor) while you are begin to use Fundamental Channel but at this point it will be very minor change, no more then .5dB.

The result of all of it shall be your confidence that your MF/Midbass balance is proper for the given location of your Midbass channel in the room. A pair of Midbass Channels shall be loading the room with thick and “crowded” sound, acting as a virtual pedal point for your MF. The channel shall also to unload it from the room with proper speed but not faster than it has to. You need to have some music that has the “cello crash” and you need to make sure that your room will be “dramatically” loaded but not over-loaded and will very “gracefully” release the load. Ironically, if everything is done poorly then the “drama” and the “grace” will not fluctuate from volume too much.

When you reach the point where you feel you somewhere near the proper MF/Midbass balance you need to think about your sound not as it a playback but as you are conducting a live orchestra and it is your responsibility to shape the balance in a way you feel it need to be. If you feel that your best MF/Midbass balance would be different at different recordings then you do not have proper MF/Midbass balance yet. The MF/Midbass balance of your system shall be more accurate than any random orchestral balance out there. Then your playback system becomes a reference against which all orchestral and recording deviations will be measuring. You personally shall have absolute confidence and supreme believe in your MF/Midbass balance. If you go in future for multi-amping then do not forget regularly check the outputs your amps (tunes are not stable) to make sure that your MF/Midbass balance still hold a reference level.

"...The result of all of it shall be your confidence that your MF/UPPER-BASS balance is proper for the given location of your UPPER-BASS channel in the room. A pair of UPPER-BASS Channels shall be loading the room with thick and “crowded” sound, acting as a virtual pedal point for your MF. The channel shall also to unload it from the room with proper speed but not faster than it has to. You need to have some music that has the “cello crash” and you need to make sure that your room will be “dramatically” loaded but not over-loaded and will very “gracefully” release the load. Ironically, if everything is done poorly [properly?] then the “drama” and the “grace” will not fluctuate from volume too much.

When you reach the point where you feel you somewhere near the proper MF/UPPER-BASS balance you need to think about your sound not as it a playback but as you are conducting a live orchestra and it is your responsibility to shape the balance in a way you feel it need to be. If you feel that your best MF/UPPER-BASS balance would be different at different recordings then you do not have proper MF/UPPER-BASS balance yet. The MF/UPPER-BASS  balance of your system shall be more accurate than any random orchestral balance out there. Then your playback system becomes a reference against which all orchestral and recording deviations will be measuring. You personally shall have absolute confidence and supreme believe in your MF/UPPER-BASS balance. If you go in future for multi-amping then do not forget regularly check the outputs your amps (tubes are not stable) to make sure that your MF/UPPER-BASS balance still hold a reference level..."

It is entirely possible that I end up multi-amping the system further than is already the case (a second pair of amps currently drives lower-bass); if not going for full DSET, I could imagine driving mid-bass and upper-bass from a dedicated pair of amps.

Once the mid-bass horns are done, I'll move the system, get it sounding a good I'm able, then post a composite of sweeps showing curves for all channels in a single frame.

Thanks much,

jd*

jessie.dazzle wrote:

What really surprised me was how good everything sounded with no filter on the upper-bass horns, and all drivers connected to the same (8 Ohm) tap; sure I'm getting too much mid-range from the upper-bass horn, but its not as destructive as I would have predicted.

Yes, Fane Studio 8M does fine in this horn to 4K and it if works alone with S2 then it is not very annoying. However, your Fundamental Chanel will produce much better 500-100Hx then Fane and this it would be a good idea to roll of the Fane sooner. The length of tail that your midbass will output would dictate not the lower MF tone but the vertical virtual centering of your system. If you feel that from your listening distance you will have some minor vertical movement of virtual MF source ten you might let the Fane’s tail to run a bit lower and it will tight the virtual MF source to you center (that I presume is the location of your MF driver). Those techniques are one of the many advantages of Macondo configuration and they were among the methods that allow me to integrate drivers from absolutely insane near-field distance.

jessie.dazzle wrote:

Yes, finding the proper level of attenuation should be fairly simple; as previously discussed, I could use the L-Pads already in place (currently bypassed) on all MF and HF drivers to establish the correct level, then build the corresponding resistive voltage dividers.

Be VERY careful and DO NOT use the wirewound L-Pads for MF and HF channels. The wirewound L-Pads are hugely inductive and then eat MF’s and HF’s transients VERY aggressively. Use ONLY not inductive fixed restors.

jessie.dazzle wrote:

"...Do the same with tweeter [tweeter and MF I assume] , and then with tweeter and bass [tweeter and upper-bass I assume]..."

What I was trying to say was that adding HF or LF channels shall not affect your perception of the rightness of the MF/upperbass balance. In the rest your corrections were correct. In my post about I did not write anything about Midbass and use upper-bass and Midbass interchangeably. The reason is the nether I not you have the Midbass channels operational.

jessie.dazzle wrote:

It is entirely possible that I end up multi-amping the system further than is already the case (a second pair of amps currently drives lower-bass); if not going for full DSET, I could imagine driving mid-bass and upper-bass from a dedicated pair of amps.

I would say that if you do for economic configuration then you would need to drive the mid-bass and upper-bass from one amp and Fundamental, MF and HF from another amp. The key in here do not let the fine MF driver to see the inductive reaction of big mid-bass and upper-bass voice coils

In he French Horns/drivers shootout thread:

http://www.romythecat.com/Forums/ShowPost.aspx?postID=15130#15130

Jessie wrote:

jessie.dazzle wrote:

…I'll definitely let you know if I get the system up and running again before leaving France (the mid-bass horns, once done, could be temporarily moved out of the way), otherwise you'll have a reason to visit the Detroit area.

It not related to anything perhaps with exception to the thread: To move audio equipment in another home.

http://www.romythecat.com/Forums/ShowPost.aspx?PostID=12886

Bu I decided to post the question in Jessie’s own thread.

As I understand the horns and the ULF section are massive. They are semi-clay-made and hardly disassembleable. So, the cost of moving them to US will be huge. Did you consider do no move them in US but to cash the entire project in France and then hire someone in Detroit to do work for you? Living aside the sentimental personal attached to the labor of your hands and the fact that you have developed a number of mean illnesses while you were mixing the wax and building the horns, I would propose that the idea to sell the system in there and then built it here is very interesting from the following perspective:

1)    The cost of labor in US and most likely in Detroit is very low. For instance the cost of labor for my Midbass project was a half of what I expected
2)    You might to review some of your initial ideas and to make it second time better.
3)    You might hold building the system until your other circumstances (financial, social etc…) would click.
4)    You will be much more flexible real-estate deals if you do not have right the way demands for perfect listening room.

The point is that I m sure that after year of living abroad and moving to US you will have something else in your priorities list. If I were you and if I move to different country then I would put the system in storage for some months/years. Anyhow, if I was you then I would problem keep the MF horns but the ULF and Midbass would try to unload in Europe. The fact the they are not finished is very good – it means the new owner will slightly modify how he would like to have them and then you juts finish the project but it will be for sale deal.

Sorry, I enter into too private subjects, this is not my business of course but I think you I proposed do have some common sense. Well, I know that if I move from my house then I will live the midbass horn behind, right in the walls….

jessie.dazzle wrote:

Romy,   I followed his advice and currently rent four storage facilities; two on either side of the Atlantic. I think its time to consolidate, but I'll definitely let you know if I need to add a fifth.   jd*

jessie.dazzle wrote:

Next time I'm making them from a double wall of 3/4-inch plywood sandwiching two inches of sand.