Too much mid bass with LSi 9

brianle

Hi,

Just got my Polk LSi 9 last month and I love the over all sound except a bit too much mid bass with the LSi 9 in my room. My receiver is the old Denon AVR 4800. Anyone has any suggestion on how fix this issue?

pitdogg2

you'll need an amp

thsmith

That and what cables are you using. I think the LSis like alot of current to sound their best or so I hear.

I suspect your AVR is not letting them sing.

Erik Tracy

How do you have the LSi9s set up location wise in your room and what is the layout.

Do you have them up close to the wall? On stands, inside a bookshelf cabinet, close to sidewalls, wall mounted, what size room and how is it shaped....etc....sounds to me like location and layout to me.

nwohlford

They do have a little overemphasis in the mid bass. Adjusting the placement can help a little (mostly make sure they are not too close to the wall behind them).

brianle

They are on a 24 inch stand 1 ft from the back wall and 2 ft from the side wall. I really doubt if the Denon AVR 4800 is the problem but I can try to hook them up with my Ayre 7e int amp.

skrol

How do you have them placed (distance to side wall, distance to back wall, stands)?

The AVR-4800 is quite a receiver but it does not appear to be rated for continuous 4 ohm loads. The specs indicate 150W into 6 ohms. This can be an issue with the LSi9 as I believe they actually dip below 4 ohms.

codyc1ark

skrol wrote: »

The AVR-4800 is quite a receiver but it does not appear to be rated for continuous 4 ohm loads. The specs indicate 150W into 6 ohms. This can be an issue with the LSi9 as I believe they actually dip below 4 ohms.

Correct! From what I understand they can dip to 2ohms, when driven hard. A lot of people report a midbass hump out of 9's, and also from what I understand, if you mod them, it will flatten them out a bit. But an amp is first. Good luck OP.

nwohlford

brianle wrote: »

They are on a 24 inch stand 1 ft from the back wall and 2 ft from the side wall. I really doubt if the Denon AVR 4800 is the problem but I can try to hook them up with my Ayre 7e int amp.

I agree that the Denon is likely not the cause of the midbass issue, but it would not hurt to try your integrated amp. I would try bringing them a little further out from the back wall (maybe 2 feet).

pyrocyborg

Uhm... stand height maybe? Depending from your listening distance, I guess you should have the tweeter at ear level or you'll lose most high frequencies and detail, thus increasing the impression that mid-bass is omnipresent. Right now, your tweeter ends up being at something near 31 inch high, while generally speaking, when he's sitting, a 5'6'' person should have it's ear level at something like 36-37 inch. As the LSi tweeters are very directional, it might give the impression than midbass is more present than treble. But as I do not know your listening distance, it might be an non-issue as if you're far (something like 12 feet away), the tweeter dispersion is better.

Yet, I understand that LSi9 requires a lot of clean power to sound "alive". So yeah, a 4 ohm rated amp is better than a AVR for this kind of job, but as nwohlford said, it might not be the culprit when it comes to your midbass issue... this is mostly a placement problem.

They need to be at least 18'' from the rear wall, or they'll sound "over" bassy. Even at 2 feet they might not be perfect. I've read that LSi9 speakers aren't for nearfield listening and are better when they're far from the rear and side walls (at least 3 feet from the rear wall), while the LSi7 do not suffer from this and can be placed 1 feet from the rear wall.

steveinaz

12" isn't very much rear wall clearance. If you can get them out into the room more, it will help significantly. Try at least 20" from the rear of the cabinets. You should notice a BIG difference in mid-bass bloom.

brianle

Thanks everyone. I moved them out 22" from the back wall this problem improve a lot. I was under impression from reading the specs that the LSi 9 can be placed closed to the back wall.

pyrocyborg

brianle wrote: »

Thanks everyone. I moved them out 22" from the back wall this problem improve a lot. I was under impression from reading the specs that the LSi 9 can be placed closed to the back wall.

Good to know! If I understand correctly, you like the sound better now? If it's the case, I'll tell you: Enjoy!!! :cheesygrin:

tonyb

Now that your mid bass problem is solved....I think, time to start thinking about powering a 4 0hm speaker with an amp before you have another problem that will cost you some coin.

nhhiep

if you look at the review that lists the frequencies for the lsi9, you will see that it has a bump in midbass. I have the same issue when power by a HK Citation Amp. So I think this is normal.

by the way, your Denon is a powerhouse. In stereo mode, it puts out more power than many low-power external amps out there.

steveinaz

Yes, the Lsi9 does have some strong mid-bass, but as you have seen just a little placement tweaking can clear it up. Most any speaker benefits from being off the back wall; rear or front ported---or even sealed. I like to always have a minimum of 18" from the rear of the cabinet. My current speakers are 20" off the back wall (front ported).

cnh

Have to agree; even with my smaller LSI-7s I'm about 20-24" from a wall of bookshelves that is behind them. They're at ear height and about a foot away from bookshelves on either side of them which is OK because the room is long and they're at least 13 feet away from me and I'm two feet from the back wall. Room is a 10' x 17' x 8.5' size (office).

Lsi bookies are very particular about placement, regardless. So experimenting with different positions is a "must". And as pointed out. Even though there is a mid-bass hump you can, through this kind of tweaking, take some of that away.

Enjoy!

cnh

pyrocyborg

nhhiep wrote: »

by the way, your Denon is a powerhouse. In stereo mode, it puts out more power than many low-power external amps out there.

It is powerhouse, but is it safe or distorsion free when powering 4 ohms speakers? I don't know... THD at 6 ohm is at 0.08%, which is far from being bad, but I suspect it must be at least twice that number at 4 ohms. It might handle the load quite well, because it's an heavy power receiver, but it'll kill some dynamics in the process.

brianle

These are used in a budget home theater setup with occasional music listening so it's hard to justify buying a separate amp for the LSi 9

tonyb

brianle wrote: »

These are used in a budget home theater setup with occasional music listening so it's hard to justify buying a separate amp for the LSi 9

Will it be justified when a speaker or the receiver goes kaput ?

pietro944

brianle wrote: »

These are used in a budget home theater setup with occasional music listening so it's hard to justify buying a separate amp for the LSi 9

Lsi 9's in a Budget Home Theater System?.......this is dumbest 4th post.....EVER!

brianle

pietro944 wrote: »

Lsi 9's in a Budget Home Theater System?.......this is dumbest 4th post.....EVER!

and you must be 16

brianle

tonyb wrote: »

Will it be justified when a speaker or the receiver goes kaput ?

I have been using the denon avr 4800 on 4 ohm speakers for 10 years

pyrocyborg

Pietro, it was totally a free insult...

I agree it might not be the perfect thing to do, even if you're on a budget, but I'm sure that it can do it quite well. However brianle, keep in mind that some 4 ohms speakers do not really go to 4 ohm (LSi7 for example rarely drops under 6 ohms and they're considered 4 ohms speakers.) On the other hand, LSi9 can drop down to 2 ohms, yet they're 4 ohm speakers... they way harder on the amp when compared to their smaller brothers, yet they're rated at the same impedance.

Anyways, if you don't crank it up too much, you won't have any problem. If your receiver doesn't seem too hot after a film session, it shouldn't have any trouble. For safety purpose (for both the receiver and speakers), you should keep it to low to moderate volumes (i.e. never try to go over 90 dB at most, depending on your room size).

I've seen people cranking their 4 ohm speakers with an entry-level receiver without any trouble (well... it wasn't instant death)... but I've seen people listening at low to moderate volumes frying their 8 ohm amp with a pair of 4 ohm speakers in a few days... If I was to play safe, I wouldn't try anything outside the mentionned specs.

VR3

Try swapping the top and bottom midbass driver...

pietro944

brianle wrote: »

and you must be 16

You must be dyslexic,skippy.........I'm 61

brianle

Pyrocyborg, it's hard to beat the lsi9 + lsic combo for $800 that is good for home theater and music

Conradicles

Guess I'm one of the 4 people on earth who liked the LSi9's stock. Great speakers...

[Deleted User]

anonymouse wrote: »

Sadly, the LSi9s, in their stock form, are very, very picky about the amp used to drive them. I used a variey of amps, including a McAlister PP150 (75WPC tube amp), an Adcom 555, a NAD2200PE and a Rotel RB991 with them. The only amp of those 4 that could make them sing was the Rotel. All the others left me wanting in bass or in overall presentation.

Then I modded the 9s crossovers, and it was a night and day difference. The difference between the amps became marginal at best. I could hardly tell the difference between the Adcom and the Rotel whereas previously it was very evident. Moreover, the lower bass performance of the 9s really picked up.

You have a couple of choices here -
1) Hook em up to a really beefy amp, with good cables
2) Mod their crossovers
3) Sell the 9s and get 7s. The LSi7s have the same sonic signature as the 9s but are much, much easier to drive in stock form

Or do both 1 and 2.

Add a B&K to that list, that's what I have and I am very pleased. :cool:

FTGV

The NRC testing shows them to have a substantial peak in their frequency response just below 100hz .I would imagine near boundary placement would make this even more pronounced. http://www.soundstagemagazine.com/measurements/polkaudio_lsi9/

Also the impedance curve shows a nasty dip into the 2 ohm range around 50 hz.

pyrocyborg

brianle wrote: »

Pyrocyborg, it's hard to beat the lsi9 + lsic combo for $800 that is good for home theater and music

I totally agree! My only point is that speakers are not the problem itself: as long as they are powered by a 4 ohm amp, they really really shine. The problem is with the fact that you only want to power them with a receiver, even if it's a beastly one.

My LSi7, as anonymouse said, are easier to drive than the LSi9... I could call them easy to drive: Hell, they're even easier to drive than a pair of RTi6/RTiA3, at least, if your amp is really rated at 6 or 4 ohm! I listen to them at higher volumes when compared to my old RTi speakers, and... my NAD326 amp stays cooler than it was doing with the RTi (where it could get warm/hot). This is an astonishing feat if you want my opinion, from both the speakers and the NAD.

I did not hear the LSi9 yet, but almost everyone say that once they powered them with a certain amp, it was really great even without any crossover mod... where they can sound either good or "not that so" with every other amp.

And by the way, I do not think that anyone out there is bashing your choice to get the LSi9/LSiC combo. IMO, it's a very great speaker at an incredible price right now, as long as it's powered adequately. Did you try them with your Ayre AX-7e? If you didn't, I bet you'll be amazed by the results (and confirm they need an amp to really shine), even though I know you probably won't start using this amp as it's probably connected to your 2ch rig with priceeeyyyy speakers :rolleyes: ... well maybe that Ayre is overkill and won't show what a budget amp can do, but it'll help understand what these speakers can do.