Dennis Had Inspire Amps

[Rosco65]

Two 8" are slightly less than one 12".

I can' give a 100% answer regarding two 8" vs. one 12" per side. If you need or want midbass reinforcement the 8" option would be advised. However, if you don't need to cross over any higher than 100hz, the F12G would give better deep bass. Some reviewers of the Salk Exotica 3 (which uses the F8 bass section) prefer them with an additional sub.

[pstrisik]

Makes sense. Thanks

[Musica Amantem]

Peter and Rosco65,

Thanks for your insights. I'm aware your conclusions and respective final implementations came after serious efforts reading, asking and trying, as well as investing ... so I really appreciate your kind and unselfish assistance. But, you guys are way ahead of me in this topic. So let me try to make this as simple as it is for me to be able to grasp these concepts which should lead me to a tailored action plan. If I'm wrong on the following conclusions (probably), kindly let me know.

1. The L12 is sealed and does not offer speaker binders, so it is for music but cannot be connected at high-level. I assume low-level inputs are good enough.

2. The LP-27a offers two pairs of stereo outs. I confused that with an integrated tube amp I own which only offers SUB outs. Sorry! So the bass would be stereo.

3. I have High Pass filters at 100 Hz, so I cannot cross over the SUB under that mark if I don't want to loose bass frequencies.

4. The 160 watts nominal (350 watt peak) of my Velodyne is so loud I have to keep it at a modest volume level, in spite of having several difussers in my listening room's walls. So, I figure anything above 300-400 watts would be overkill, especially in stereo mode (2 SUBs). Post edit: I suspect you may be right and the kind of bass which boosts "oomph" may require much more "juice". Let me know what you think.

5. If stereo is the way to go, I could stuff the front-firing port of my Velodyne with some material to simulate a sealed unit and avoid possible rumbles. I had not thought of that until you brought it out. Then, I could look for another 8" sealed unit of comparable characteristics, or even a more powerful one and trim it down through dial controls to the Velodyne's levels. Down the road I would get another exact copy of the new sub and eliminate the Velodyne.

6. My cost is about double the nominal one in these heavy things, simply because I ship them to Miami, but then it needs to go air freight and through customs, all the way down here, making for a significant cost mark-up. Therefore, the smaller and lighter, the better, provided it solves the problem.

7. Trial-and-error is not an option because I cannot return the stuff due to prohibitive shipping out costs (worse than the other way around due to low export volumes), nor can I sell it locally as there is no second market here for these specialties.

I could also start with one (either 12" or twin 8"'s) and eventually retire my Velodyne and get a second new SUB (after 10 years with me, it looks and sounds as new!).

Two splitting RCA "Y"'s should do it. I just would need another pair of bass cables (mine are Blue Jeans bass cables).

This is as far as I can get for now. Thanks again. I'll give these ideas more thought, while doing some research whenever I find the time.

[Rosco65]

MA - your unique position presents challenges that most of us do not face. Shipping is reasonable for me, and the secondhand market in the US is pretty strong. I purchased my like-new F8 subwoofers for about 60% of retail from the previous owner in San Francisco. If I decide to trade them, I can find a ready buyer with little trouble.

You are faced with a number of challenges: shipping and import duties make your purchases more expensive, you have the inability to audition equipment first, and if you change your mind you don't have a market for resale.

You've given us some parameters: you appear to be happy using the FMOD filters at a nominal 100hz (the actual frequency may be slightly different), rolling your Tektons off at either 6 or 12dB/octave depending on who you believe. In either case, these shallow slopes still give some reasonable bass below 100hz, helping to solidify the image at your speakers (as opposed to a subwoofer). You're looking to add a better bass foundation to these speakers that would give you more dynamics and impact.

If I were in your position I would do this:

1. Buy a Crown XLS1502 pro sound amplifier. This class-D amp is two channel, sounds great at all frequencies, has a built-in adjustable crossover, and has a ton of power. This will be your subwoofer amp for either one or two channels.

2. Buy or build two or four passive subwoofers. Your best bet would be four (two per side) sealed 8" subwoofers. My personal choice is a nicer version of Ed Schilling's Bucket Sub. Ed uses 5 gallon buckets, but you can substitute the .75 cubic foot knock down enclosures from Parts Express (you can get it already machined for an 8" driver: parts-express.com/denovo-audio-knock-down-mdf-075-cu-ft-subwoofer-cabinet-for-dayton-audio-8-reference-seri--300-7075?utm_source=google&utm_medium=cpc&utm_campaign =pla The drivers are the Peerless paper coned SLS woofer parts-express.com/peerless-by-tymphany-830667-8-paper-cone-sls-subwoofer--264-1102. These are 8-ohm drivers so you can use two configured in dual mono or four for stereo. Throw in some stuffing, paint and odds and ends and you have a DIY "Swarm" subwoofer system.

The 8" drivers can be operated up to about 200hz, and with 4 x 8" drivers in your room you will have fantastic, even bass. And if you decide to change you mind later, the modular aspect of this configuration allows you to change your configuration later.

[Wgarcia]

Note that pro amps (including the above mentioned Crown) have annoying fans, and I don't mean rabid supporters. I'm a decades long live sound mixer/designer/tech ("hey dude, it's TOO LOUD") and musician and I can't even use one of those in my recording studio where I use a fanless power amp (and I don't mean one lacking rabid support). So your "blacker blacks" background could be marred by the sound of tiny fans (and I don't mean rabid yet small supporters).

[Musica Amantem]

Rosco65 wrote: " ... 8" drivers can be operated up to about 200hz, and with 4 x 8" drivers in your room you will have fantastic, even bass"

I believe the most important thing I've learned from these discussions is that my lacking "oomph" problem with large-scale orchestral music can be fixed through proper SUB implementation.

Since my Velodyne makes a 'booming' sound I don't appreciate when its volume is increased beyond what is ideal for the Inspire levels, I had been under the impression more "subbing" was not the way to go. Evidently, my experience has been related to SUB design / configuration issues, and now I'm considering the several possible options, between 12" and 8" SUB drivers for enhanced stereophonic subbing. Your particular suggestions are being considered in this context. Thanks!

[Rosco65]

The fact that your Velodyne makes a booming sound is a red flag that either your sub is suboptimum or faulty or that you feel you have to turn up the sub gain to make up for something you are missing.

Some buyers of the Omega Outlaw speakers with built-in subwoofers found that they were still unsatisfied, despite having stereo 8" subwoofers filling in the bottom of their RS5 drivers. It turns out a number of owners have found that while the subs fill in the bottom, there is still a shortfall in the mid to upper bass (100-500hz) that left the speakers sounding "thin". A lot of the musical content we attribute to "bass" is actually midbass and upper bass.

While the deep bass offers a foundation to music, the meat of what we perceive as bass is really from 40hz and higher. Classic speakers that rock and have great impact, such as Altecs, Klipsch, JBL L100's, and Yamaha NS1000's don't really have very deep bass but have a lot of power and impact in the midbass.

[Bombadil]

It "might" be true that your lack of "oomph" can fixed via a subwoofer.

But it is my experience that when it comes to classical music, a lot of wattage is needed through the midrange. Large scale orchestra crescendos are not in the sub-100Hz region. When one is listening to uncompressed, wide-dynamic range classical at higher volume levels, the wattage demands range across a wide frequency. In an uncompressed classical recording, there can be 20dB peaks (requiring a 100X power increase/reserve) from your average volume level.

My 17wpc Inspire cannot handle these peaks even when all sub-100Hz energy is filtered from the amp. In fact, it can't even come close. Some peaks and transients need well over 100 watts. This is into my 91dB speakers.

At my normal volume levels, the Inspire does a very good job.

[Rosco65]

Originally Posted by Bombadil

It "might" be true that your lack of "oomph" can fixed via a subwoofer.

But it is my experience that when it comes to classical music, a lot of wattage is needed through the midrange. Large scale orchestra crescendos are not in the sub-100Hz region. When one is listening to uncompressed, wide-dynamic range classical at higher volume levels, the wattage demands range across a wide frequency. In an uncompressed classical recording, there can be 20dB peaks (requiring a 100X power increase/reserve) from your average volume level.

My 17wpc Inspire cannot handle these peaks even when all sub-100Hz energy is filtered from the amp. In fact, it can't even come close. Some peaks and transients need well over 100 watts. This is into my 91dB speakers.

At my normal volume levels, the Inspire does a very good job.

One of the guys in my local club is an audio engineer and has been involved in recording professionally for decades. His position is that it is almost impossible to avoid instantaneous clipping during replay of musically-demanding pieces. While he and I differ in our opinions about many things, we are in agreement with this.

He designs his systems for 110dB output capability. This would allow for 90dB playback with 20dB peaks. An Inspire HO amp with higher-output tubes will give you about 10sB of headroom. Unless you are running 100dB speakers or listening at very quite volumes you are likely to encounter clipping at some point. This is where - IMHO - the character of clipping comes into play. In the Inspire, the SEP overload characteristics are comparatively benign and while we will encounter compression it is more likely to be unobjectionable. If our amp has the IIPS, this characteristic is even better.

I have a HT system and a two-channel rig. My HT is designed around >110dB capability (97 dB speakers with 20wpc). My two-channel rig is designed around 108 - 112dB capability (95-99dB speakers with 20wpc). Since I am listening at about 2.5m in my HT room and 2m in my two-channel room, my maximum output at my listening position is 108dB in the HT room and 107dB in my two-channel room, not counting room gain, which is negligible above 200hz or so.

[pstrisik]

Originally Posted by Musica Amantem

Peter and Rosco65,

Thanks for your insights. I'm aware your conclusions and respective final implementations came after serious efforts reading, asking and trying, as well as investing ... so I really appreciate your kind and unselfish assistance. But, you guys are way ahead of me in this topic. So let me try to make this as simple as it is for me to be able to grasp these concepts which should lead me to a tailored action plan. If I'm wrong on the following conclusions (probably), kindly let me know.

1. The L12 is sealed and does not offer speaker binders, so it is for music but cannot be connected at high-level. I assume low-level inputs are good enough.

2. The LP-27a offers two pairs of stereo outs. I confused that with an integrated tube amp I own which only offers SUB outs. Sorry! So the bass would be stereo.

3. I have High Pass filters at 100 Hz, so I cannot cross over the SUB under that mark if I don't want to loose bass frequencies.

4. The 160 watts nominal (350 watt peak) of my Velodyne is so loud I have to keep it at a modest volume level, in spite of having several difussers in my listening room's walls. So, I figure anything above 300-400 watts would be overkill, especially in stereo mode (2 SUBs). Post edit: I suspect you may be right and the kind of bass which boosts "oomph" may require much more "juice". Let me know what you think.

5. If stereo is the way to go, I could stuff the front-firing port of my Velodyne with some material to simulate a sealed unit and avoid possible rumbles. I had not thought of that until you brought it out. Then, I could look for another 8" sealed unit of comparable characteristics, or even a more powerful one and trim it down through dial controls to the Velodyne's levels. Down the road I would get another exact copy of the new sub and eliminate the Velodyne.

6. My cost is about double the nominal one in these heavy things, simply because I ship them to Miami, but then it needs to go air freight and through customs, all the way down here, making for a significant cost mark-up. Therefore, the smaller and lighter, the better, provided it solves the problem.

7. Trial-and-error is not an option because I cannot return the stuff due to prohibitive shipping out costs (worse than the other way around due to low export volumes), nor can I sell it locally as there is no second market here for these specialties.

I could also start with one (either 12" or twin 8"'s) and eventually retire my Velodyne and get a second new SUB (after 10 years with me, it looks and sounds as new!).

Two splitting RCA "Y"'s should do it. I just would need another pair of bass cables (mine are Blue Jeans bass cables).

This is as far as I can get for now. Thanks again. I'll give these ideas more thought, while doing some research whenever I find the time.

Randy offers good advice regarding DIY subs when shipping and used market are obstacles. I have DIY cables, refurb of vintage AR2ax speakers, building of Nelson Pass designed Amp Camp Amps, etc. These projects were fun in their own right and add an extra sense of pride and accomplishment.

Brian/Rythmik also sells the drivers and plate amps separately. You can get the DS1200 and plate amp for $599-$629 depending on the amp you choose. Then build or have built locally, the enclosures. Brian is helpful with plans and the enclosures for basic 12" subs are pretty simple in design. This would reduce shipping significantly. It would also allow you to get an F12 for less than the full assembled cost plus shipping.

Regarding your points above:

1) I have high level inputs on my F12's, but never use them.
2) I guess your subs would be stereo in this case unless their is a way to combine the L/R signals going to the subs without affecting the stereo signals to the mains. There may be, but I don't know how if there is. If the subs have L and R RCA inputs, I think you can run both channels to both subs, but not positive. If you are going to use your Velodyne with a new sub, it may be an issue since each channel would perform very differently in that FR. If you were doing this on the way to getting a second of the same new sub, then it is just an intermediate step.
3) With a fixed high pass, you are limited to that frequency unless you cross higher and it sounds good to you. It may if the 100 to 200 range of your mains has a dip there. 100Hz is a very workable point though.
4) Wattage is not just about volume. It also affects dynamics and distortion. Sub bass frequencies require more power than any other FR.
5) Worth experimenting. You've said elsewhere that your Velodyne is bloated sounding. Lots of factors contribute to that, but more power might help slightly, servo would help more, cabinet and driver quality also. Making it sealed will reduce output a bit, but may help reduce the ringing (which makes for much of the bloated sound).
6-7) I understand from living "up here" in Alaska. Shipping is painful. I imagine even worse for you. Is "down there" Brazil? That memory is from some time ago when we might have had a similar discussion about other equipment, unless that was someone else.